Why does it keep overheating?
 

Hi,

i have a 1992 SL SOHC over 150k miles.... i did a tune-up: plugs/wires, fuel filter, air filter, pcv valve & replaced the coolant. the damn thing is purring like a kitten...runs great. but now after the tune up, it overheats. it warms up slowly as ususal...then fan kicks on right when the temp gauge reaches 3/4 but it doesnt cool the engine down like it did before the tune up. it just keeps creeping into the red and overheats. After i refill the coolant and start the car i can see the coolant being sucked down into the engine (then i top it off) so i dont think the water pump is bad.

so far i've:
replaced thermostst
replaced coolant temp sensor
replaced coolant temp sending unit/sensor

what else could it be?

thanks

Sounds like an air-lock in the engine somewhere

are both top and bottom rad hoses getting hot?

may not be a water pump issue but maybe a partial clog of crap has lodged somewhere (???)

Or an air pocket as OA suggested though it sounds like you're burping it.....
Are you sure pressure cap on the reservoir is good/sealed tight?
Are you using a 50 50 mix? (sorry but someone had to ask)

Any stop-leak or equivalent nasty products ever added ?

I did notice that the top water hose is NOT getting hot. i replaced the water pump not long ago....i know it could be bad again but i checked it for leaks and the whistling noise it makes when going bad. all looks good. how do i check for blockages or air pockets? i've never added any kind of stop leak in the system.

the pressure cap is on there tight and i'm using a 50/50 coolant from Advanced Auto ...i'm NOT adding any water.

thanks for your help so far

Well, I'd pull the thermostat back out, and drop it in a pan of boiling water, to make sure it operates correctly. Assuming it does, make sure you reinstall it properly .....

Ocean Archer beat me to it, sounds like the thermostat is not opening.

in boiling water?
how exactly does that test it? what should i be looking for?

If the stat opens in boiling water, that means the stat is opening while it's in your engine. If the stat is opening that means it's not stuck shut. If it's not stuck shut then the stat is not the reason the car is overheating. Get it?

PS: If thats more then your able to understand you need to bring the car to someone that does.

of course i understand the WHY of the boiling water method...i've kept the car running on my own for over 17 yrs....what i meant was what do i look for/how do i know if the stat is working properly. not many ppl have seen a stat open/close in a pot of water. i was just wondering what to look for. but i imagine it will be obvious.

I imagine

I know this is gonna sound silly, also but...I have heard of peeps installing the t-stats upside down before, and this exact result happened....
Did you re-install the same way it came out?
Tim

i did re-install the same way, thanks for the input. at this pint i'll check anything.

i removed the stat and did the boiling pot of water test. it opened up just fine. i also tested the old one i removed and it opened up just fine as well. the car overheated before i replaced the stat so i kinda figured the problem was not the new stat i installed. it seems to me that this has something to do with the way i drained the coolant. maybe i did something wrong. i drained it from the radiator valve and did not remove any hoses so i'm sure not all of it drained out.

i reinstalled the new stat and it still overheats. Also, the top hose is not getting hot at all. the bottom hose does but i find it hard to believe the water pump is bad because i replaced that just over a year ago.

so far i've:
replaced the stat, coolant temp sensor, coolant sending unit/sensor, checked the coolant cap for tight fit, removed/reinstalled the coolant tank, refilled with only 50/50

Sounds to me like you've got a blockage somewhere since you've replaced two thermostats and the top hose isn't getting hot. Maybe you need to pull that radiator out and take it to a shop and have them boil it out for you.

Since the top radiator hose is not getting hot, I would suspect the blockage is somewhere inside the motor, not in the radiator. May need to take it to a radiator shoppe, and have the motor itself pressure/reverse flushed ...

No, you probably don't. And a lot of us older members who have been grandfathered into being shade tree mechanics have maintained cars that when designed did not have thermostats, they were kept warm in the winter by placing a piece of cardboard over the radiator to cut down on air flow through them. They also did not need to be kept warm as they had no heater, if fact I owned and maintained one that the only option on the car was a jeweled dashboard light cover (1 light) that sparkled when you turned it on and it was a dealer option. No shock absorbers, and only one tail light. A thermostat was an after market part you bought and installed in a radiator hose which you bought and installed if you also bought an aftermarket Arvin Heater and installed it.
We forget that some people have never seen parts or in many cases have no clue what they are that were standard for us to replaced some times 2 times a year just to keep them running.
Some of us are stupid enough to say:
"They do not make them like they used to!" Which in very rare exceptions when it was not uncommon to spend a years wages on a car new ($500.00) when you could buy a quality what now is referred to a Classic and not the bastardized use of the word to describe a '55 Chevy which is nothing more than a very popular mass produced hunk of iron built shoddy with little quality control on an assembly line to a price and a budget, but a real classic as defined by the classic car club of America that when new was largely hand assembled to the best of standards using premium material to manufacture them with and designed by artists of design not by some budget analysis committee such as those responsible for the Marketing of Pontiac, Oldsmobile and Saturn and when you owned a caddy people knew what it was and were suitable impressed. And it cost not $500.00 but 100 times that. And they do not make them like they used to. Today's **** box models are more reliable and made with better tooling than any of the "Classics" ever were and will run longer, with fewer problems and better performance under conditions of pure neglect which would kill cars from yesterday with in months. Not years.
I blew my first car up in 3 months. Not from abuse. Pure ignorance.
The thermostat operates like a heat operated faucet. The bellows looking thingy will expand and contract with heat and the rod that attaches it to the round plate that covers the hole in the center will cause it to move and open the hole allowing water to pass through it.
They fail or it was installed backwards. Both can happen.
Put it in a pot of water, heat the water to boiling. Boiling is 212 degrees unless you have a pressurized radiator and you do, the plastic tank on the S series Saturn serves as the top tank and the cap pressurizes it. And boiling is now some what higher. I'd have to look at a book to come up with a number. That is why I buy them. They typical Computer Controlled engine runs with a 190 degree thermostat not because it is a more efficient number to run at, When I build a street racer motor I run them with a 140 degree thermostat. But it is a temperature that assists in maintaining smog criteria, a concern that my 1930 car never had to deal with but it cost $500.00 new. And I can get it to pass smog testing that way and I do not have to satisfy the federal regulation which is more stringent.
As the water heats up you should see the dime sized valve piece begin to move before the water actually boils.
What way does it install? Don't remember, I think they are marked which way the water goes through them with an arrow. Water flow is from the hot engine to the radiator so the arrow should point away from the engine. For things I don't remember, I open a book.
As to the shot about not knowing what you are doing.?
The fact is that a large amount of people buying what is now a 20 year old car for the most part is largely clueless as to what makes it work. And generally thinks they know more than then they do and frankly that IS hard to work with on a public forum. Which is generally why you go to a junk yard you find a lot of high dollar project cars sitting there because who ever started them did so by purchasing a lot of high dollar parts that were of no value unless you knew how to use them and got dejected at the amount of work it was going to take to finish something, so threw in the towel and trashed it.
An example of that.
A $9.00 or more bottle of anti-freeze half full of water that comes from a faucet for free. Prior to having those you bought a $9.00 bottle of anti-freeze. It now costs twice as much to fill your radiator with anti-freeze, marketing efforts besides, with care faucet water works just fine, has for years and will continue to do so. It is extremely rare that it does not. And if you know what you are doing you deal with it.
But the manufacturer discovered a way to product their product at 1/2 the previous cost. The accounting department is thrilled, you are disillusioned but happy and the water in the bottle came from a facet only now you are paying $4.00 for a half gallon of it. It would be cheaper to buy a gallon of water from the grocery store. Cheaper yet to fill an empty container from your faucet. That is what I do.

i removed the new t-stat and tested it in a pot of water...it opend up just fine. i also tested the old one and it was fine, too. it looks like you guys are right,,,i may have to take it to a shop to get checked. it just seems crazy that it was working and cooling just fine before the tune up. i know it HAS to be something i did...perhaps draining the coolant messed something up.

Check your lower radiator hose and make sure it didn't suck flat on you when you drained the radiator. If that hose collapsed, you won't get full circulation. Hell, I'm running out of ideas.

Something does not make any sense and taking the car to some place to spend money on it before it makes sense does not sound like a real good idea.
Looking at all the information here and going back to the beginning I wonder if the words;
It over heats
is not being misinterpreted by each person offering advice including myself.
You went through the procedure of draining coolant.
It went out the drain plug of the radiator and their is nothing wrong with draining things that way. That is the way it is designed to work.
You added fluid through the cap in the plastic tank next to the fender on the passenger side of the engine compartment.
That is the way it should be done.
You used the new miracle coolant of half water and half anti-freeze. yes I am being smart allecky and no I don't like paying half of $9.00 for a half a gallon of free water. That is besides the point. It makes no difference to the engine what you pore in there as long as it is liquid. If I am not mistaken it should have taken a little over one gallon container to refill.
Now there is a procedural way to go about that to insure that things are full as they should be and that is to initially refill through the tank. When it is full start the engine and also turn on the heater and turn the fan up high.
Why?
That opens up the passages going to the heater to allow water or coolant of Vodka if that is what was used to thoroughly work it's way through all of the passages. and as it does it will suck fluid from the tank into the cooling system. This will require you to add coolant to the tank to top it off.
You said you had to do that. As you have been messing with this for a while this has probably been done a number of times with the same result.
An additional benefit to this simply is with the heater running full blast and the engine is getting warm you should also feel the heat coming from the heater.
Do you?
Because if you do, that means the coolant is circulating.
Now you have an indication coolant is circulating.
1. It sucked coolant out of the tank.
2. Hot air is coming from the heater.
Hot air could not come from the heater if the coolant was not circulating.
So if hot air is coming from the heater that is a good indication the water pump is working.
As a side note I have been in the desert with a car running hot and having to turn on the heater to help cool it down. A trick often forgotten. The heater is also a baby radiator with it's own electric fan and it will help keep an engine cool. It gets damned hot riding inside the thing in the desert but you get away with being able to drive the car the car.
You say the gauge indicates that the engine is getting hot so the sensor and the gauge work.
You say the fan kicks on which is an indication that sensor for that works and on some saturns they are the same sensor on others there are two separate ones. I don't remember which one you have, my 94 has two.
The point is they work.
The only other thing I can think of is to go through this hassle with the cap off of the tank and observe what is going on inside the tank through all of this.
If it is truly over heating the water in the tank should pretty much be visible to you so you should see movement of the coolant and you should be able to stick a finger in it and feel heat and if you have to you an put the cap back on at any time.
You say that you had to stop and refill the coolant because it got hot.
I am going to assume what you meant is the water got hot enough to boil and it came out and got all over things and you had to let it kool and clean up the mess.
Now if I am right in my interpretation of what you said along with you said you removed the tank and changed the thermostat let me think about what is happening and give my comments.
You have replaced or removed and put back on a number of parts!
Why?
It over heats.
How can you tell?
The gauge says it is over heating.
The water is boiling.
Both of these things are good indication of over heating.
The lower radiator hose gets hot the upper one doesn't? That makes no sense.
If heat is seen and felt through out the cooling system why would one hose not get hot.
It would if there was a blockage somehow.
Yes a hose can collapse as Ruby says. They are usually very old and soft and you can both see and feel it most of the time.
But
you are not seeing that at least you don't say you are.
I have no clue why one hose is not hot. I for the life of me can not picture in my mind how the hoses are routed so water passes through them. But with the remote tank it is feasible that if that hose going to the tank is the one you are feeling than it is reasonable to assume that water does not routinely pass through that hose. It does no more than serve as a connection to the tank.
Everything you say indicates that water is passing through the system.
The tank is not part of the pass through system, it serves as a reservoir to see to it the system is full.
If the coolant got hot enough to boil out of the tank the hose going to it should also be hot.
But if the system does not reach boiling then it is possible that hose would be cooler than others.
As I am typing I don't remember and while I have pretty much done all the things you have done my memory as how the hoses actually run is lacking. I dunno. But if the heater is putting heat out, water is circulating.
And I'll bet if the water is boiling all hoses are hot.
But I am not there to touch and feel myself.
However every thing you say seems to indicate that the engine is over heating.
So for the moment I am going to believe it. Because that is logical.
I'll let you figure out why a hose is hot or not.
So to change the subject.
When you start your car does it start making a noise like some one threw a hand full of pea gravel up the exhaust pipe?
Maybe even when you step on the gas the same noise is made for a second or two.
Because if it does, the catalytic converter is coming apart and pieces of it are rattling around inside the container. They in turn are plugging the exhaust pipe up which causes the engine to run hot.
It runs hot trying to get exhaust gasses to go out the exhaust pipe. Performance can be down but in some cases not noticeably.
If that is the problem and can be proven, replacing the catalytic converter will generally solve that problem.
Mine failed that way and drove me nuts until I figured it out.

Around my neck of the woods muffler shops use a high flow generic cat which is generally installed for about $150.00 I have used 2 or 3 of them and have no complaints.

e

What's crazy about your situation is that the overheating STARTED after you did the tune-up and drain/refill of the coolant...so basic level instinct suggests that something occurred during one of the tune-up processes that didn't go the way it was supposed to...sounds like the only one of your tune up items that would directly affect the present condition of the vehicle would be the coolant drain and re-fill...can you describe your exact method for us and let us see if something might trigger a thought or two?

hi guys...
i really appreciate all the help.

let me start by answering timmerz then i'll answer uncljohn and so on.

timmerz, what i did to drain/refil coolant:
raised the front passenger side with a jack/jack stands; opened the lower
drain valve of the radiator to begin the flow; removed the resevoir cap
to make it flow faster (i was expecting lots more to come out but it didnt
even fill a medium sized bucket...about 1 gal and a half came out); closed
the lower valve; lowered the car; refilled the resevoir; started the car;
waited for the coolant to drop in the resevoir (at this point i didnt know
i should have the heat on); refilled 2x to top off; waited for engine to warm
up watching coolant level in case i needed to add more. as eagine heated the coolant in the resevoir started rising; i replaced the cap; the gauge reached 3/4 and the fan turned on as it usually does; gauge kept rising slowly into the red and i turned off the engine; coolant started leaking from around the resevoir cap (not spewing or spraying and no smoke...just a steady stream from around the cap); i let it cool off then started to whole replacement of parts proceadure (T-STAT; BOTH TEMP SENSORS).
NOTE: i've noticed bubbles in the resevoir coming from the lower resevoir hose.

uncljohn,
when i first refilled the resevoir i didnt know i should run the heater...after it overheated the first time and i started researching and found that info. the second time i refilled the coolant i ran the heat. it took a little but to get hot but it did get hot. it wasn't until it overheated and i refilled it a 3rd time that i realized the top hose from the radiator to the engine was not getting hot. the bottom hose from the radiator to the engine does get hot and is not flat or collapsed. still looks brand new (but its very old). I'll check it again today to make sure im not crazy or getting all this mixed up (since i've done this about 5 times now). gaige is working fine...fan kicks on like clockwork at 3/4.. there are 2 sensors, coolant temp sensor and coolant temp sending unit. i have observed the coolant in the resevoir...after the car overheats, i let it cool down then i refill and it goes down a little...i top it off twice and then it doesnt go down any more. i leave the cap off to make sure. as it engine heats, the coolant rises until i have to put the cap back on. i have not put my finget in there to see if the coolant is in fact hot, though. you are correct about me refilling...the water got hot enough to boil over and came out and got all over everything (with the cap on) and i have to clean the mess. re the noise when started...no. i don't hear anything when i start it. it starts smoothly and sounds really good. engine runs smooth. it even sounds normal when i step on the gas.

Rubehayseed, lower hose looks good. same as it has always looked. its old but it looks brand new and feels firm...not flat or collapsed.

Have you tried getting a new reservoir cap and replacing it? I find it strange that your coolant spewed out from around the cap unless you didn't have it tight. Perhaps the seal on it is shot and not holding pressure?

Rube -- it is indeed a possibility -- I've had mine spew coolant in the same manner even when the leak was not from there.

My concern is the upper rad hose not getting warm -- which says circulation issues to me.

Is it the orig radiator? I believe they circulate in the bottom and out the top (someone please correct this if I'm wrong)

So a cold upper rad hose would maybe imply a plugged radiator?

(??)

Well Derf, you and I have already suggested a blockage, so I don't know what else to suggest. Maybe someone will come up with something else.

Heart breaker, heart breaker. You know what I'm referring to! LOL

Over the years I have owned and maintained an eclectic array of automobiles some of which actually ran well others? Had trouble getting out of the driveway and a few had cooling problems.
I've never owned one that would boil water and have the upper radiator hose stay cool.
So something is drastically wrong with the information being received.
Also when my 94 SC2 had the partially plugged catalytic converter it got hot enough to scare me on occasion over the period of time it took to figure it out and fortunately not hot enough to damage the car.
Every thing that has been said indicates the engine gets hot enough to loose water through the pressurized tank from boiling.
Gauge reads hot, heater blows hot air and water spurts out.
Unless there is something wrong with the tank and it is indeed no longer pressurized but allowing water to escape before it boils, but normal expansion of hot water thus confusing an issue. My car wore a hole in that tank from a screw head that was touching it and water could get out of that hole, the placement was just low enough so water level in the tank would not get low enough to trigger the sensor that detects low water unless I turned a corner hard or jackrabbit started.
Visually by the time it got that low I would see a drop or two and related that what was seen to the beginning of a crack in the plastic end caps of the radiator. Thus was fooled by the symptom. And the car ran pretty much fine with the pressure gone from the system in the mean time.
If this car was mine and I was as confused as I am I would pull the thermostat and repeat the tests run with the cap off of the tank and see if the following would happen
1. It repeats the getting hot mode by all previously mentioned symptoms.
2. The top hose does not get hot.
AND
3. Stick my finger in the water in the tank and feel what the temperature is or somehow measure it so I would know what ever is going on with the water in the engine is also showing up in the tank.
4. Thus letting me know what is happening so I can relate cold hose to tank happenings.

I am having trouble with the word blockage.
I have yet to see a blockage that keeps water from circulating unless the thermostat is closed.
Yes it opened in a pot of hot water, not it has not been determined it is backwards.
If it is in my pocket, it is not part of the problem any longer.
yes I have seen collapsed hoses, generally because the spring inside them is rusted away and the rubber is rotten. But when looking at them with a hot engine over heating they actually look collapsed.
What I need to do is go out and look at my car to figure out what the the top hose does. Or if for some reason there is more than one hose at the top and there is a bit of a confusion going on as to what a top hose is.
I under stand the reason for a remote tank. Clearance issues with the hood.
Early 60's T-birds were that way. Pontiac Fiero's were too for different reasons, one of which was directly related to causing overheating problems with the car. The filler cap was in the trunk in back with the engine. The over flow tank was in the front next to the radiator and about 8 inches lower than the top of the engine. There was a car that if the lines were not burped correctly the top of the engine never got water, which would have been solved with a system similar to what the Saturn uses.

And when I replaced my tank on my Saturn and what I would call the over flow line, the one that directs water from the tank to the ground in every other thing I own, went instead to some place on the intake manifold and I never found out why or what the reason was, I realized there was something about the Saturn Cooling System that I was and still am, clueless about.

While I can not justify a logical reason to pull the thermostat and see what is taking place, if it is not there and everything works o.k. except it takes a long time to get warm, it then can be assumed it has been installed backwards some where in the process of trying to figure out what is wrong.
To be honest, I don't even know if it can be installed backwards or where to look for it. East West engine configurations have some strange non-standard ways of doing things. And Saturn if I remember correctly was West East with the engine on the passenger side rather than the drivers side as many popular front wheel drive cars were when the came out. I'm not sure that is true now, but I sort of remember it being a questionable thing when these were new.
What ever the reason is I am still old school, you drive the rear wheels not the front.What a silly way to design a car. Only the Cristy a car made famous by Barny Oldfield and a bear to handle and the Citroen made by the French whose infamy has nothing to to do with success, build front wheel drive cars.
yuh, I know, others do now too. It just frosts me to see the French right in something.

try making sure the rad is sitting higher than the block when you refill -- and loosen the top rad hose to let the air out while filling

I've been away for a few days but I'm back and working on this same problem again.
I think I've confirmed that there is no blockage. I raised the front of the car on ramps as derf suggested. I drained the system again via the lower radiator drain valve and I removed the lower radiator hose and the top hose. I then replaced the two hoses...but on the top hose I left the clamps off so that I can see if coolant leeks (as an indication that coolant is flowing). I put the clamps back on the lower hose and made sure it's tight and not leaking. I then filled the reservoir until coolant was draining from the radiator valve. I then closed the valve and started the car and turned on the heat to full and the fan started up. The coolant level in the reservoir started going down and I began topping it off slowly until It would not take any more. I noticed coolant leaking from the top radiator hose where it connects to the engine so I put the clamp back in place and the leaking stopped. Then I saw coolant leaking from the other end of the top hose...where it connects to the radiator...so I put that clamp back in place as well. Now there aren't any leaks and coolant seems to be flowing normally because the top hose is getting nice and hot as it should. The air in the car is coming out nice and hot as well. By this time to temp gauge was at the half way point (straight up) so I turned off the heater...but the fan kept running and never turned off. I let the car run for a bit and kept an eye on the temp gauge. It kept rising right into the red and never cooled down. When it reached the red I turned the car off (and let out a few choice words). But the fan kept running with the car off. I turned the key back to ACC then off and pulled it out and the fan stopped running. This time the coolant did NOT begin spewing out from around the reservoir cap as it did each time before.
The car clearly overheated because it went into the red so I'm no closer to solving this problem than I was two weeks ago. I've checked for anything blocking the front of the radiator and all is good.

I would really appreciate any other ideas.

I'm going to ask a different question here, because I've looked back over the thread, and cannot find the answer --> Does the car overheat just in "around town" driving, or does it overheat at freeway speeds as well?

Man, I am frikkin' stumped here...if there is AIR-FLOW through the radiator and there is COOLANT CIRCULATION there shoud be NO reason for an overheating situation like cadman is describing...
It sounds like you have the coolant circulation happening, I guess...and I think you said earlier that you had the water pump replaced? The fact that you have heat coming from the heater through the dash would seem to indicate that the circulation is good.
So...let's try to figure out why the exessive heat isn't being drawn out by the fan...
You said in your last post that the fan started as soon as you started the car...as far as I know that shouldn't happen unless you have the a/c on on startup...one of the smarter, more knowledgeable guys here will have to address that one...
I think you need to see what's up with the fan, make sure that the blades are turning when the fan motor is on, and that the fan, if working correctly, is pulling large quantities of fresh air through the radiator...if necessary, get a high pressure garden hose and squirt it through the radiator from the front, see if the water makes it through into the engine compartment...that's what I would do, and if it's wrong to try it I'm sure one of the better mechs we have here will call me an idiot...:rolleyes:
If those two things are happening smoothly, air flow through the radiator and good coolant circulation, your Saturn should be able to sit in one place and not cook, it was engineered to stay intact.

Bad head gasket, bad head ......... ?

might want to get the system pressure tested at this point --- if the system does not pass the pressure test you may be dealing with what RJ suggested.

Does your oil look normal or is it like a milkshake?

oceanarcher....it overheats just sitting in the driveway.

timmerz... seems like im getting good air flow. in fact...i replaced the fan motor yesterday as someone else suggested but it made no difference. still blows the same and still overheats. (brand new fan motor)

another symptom... i should have thought of this a long time ago.... i used my code scanner and got a code 15 (coolant temp sensor voltage high). i replaced it (for the second time since this started) and it made no difference.
something i forgot to mention early on (code 15 reminded me)...while doing the tune-up, i pulled the wire for the coolant temp sensor by accident and it came loose from the in-line connector that has the shrink wrap around it (not from the connector that goes on the sensor). i couldnt get the connector back on the wire so i removed the connector and spliced the two wire ends together for a good connection. i wonder if that might be causing an issue?

Could be a factor, maybe a BIG one...let's see if the guys think so...that code is huge, might be the entire reason you're having a problem...and possibly the wire you pulled might have another fault other than where you spliced, due to the stress of the pull...
That's got to be the main problem, at least I think you might have narrowed it down to the nubbin...

CadMan --

I guess I asked my question the wrong way --> does the car overheat when driving at freeway speeds?

The reason why I'm asking ... there's a possibility that your fan is failing to turn fast enough to cool the engine while sitting still

It sounds like you may have damaged a wire/sensor/connection when you did your tune-up. Timmerz is probably correct.

Also heat coming from the heater core doesn't indicate good flow , only that hot water is present. So a blockage in the radiator , heater core or engine is a definite possibility.

actually, i have not driven after the tune up. i've been afraid to get stuck. i'm not sure if it will overheat at freeway speeds. it started overheating the first time i started it after the tune up and ever since. however....it never overheated before the tune up. the fan cooled it down perfectly once it reached 3/4 temp.

i checked the sensor wire and the splice i made it tight and good. i removed the elec connector from the sensor and inspected the connector/wires and it looks fine. there doesnt seem to be any other damage other than the two ends i spliced back together on one whire. the other wire going to the elec connector still has the metal connector peices with heat shrink inline and those are still connected good.

what i pulled out by accident was the wire from one inline metal connector. i couldnt get it back into the connector so i removed the connector all together and just spliced the two ends together. thats the sensor i'm getting the code 15 from. (high voltage). other than the splice....the wires look perfect so i'm not sure what is causing the problem.

As others have suggested check the condition of the oil if you haven't done so already. (eliminate possible failed head gasket)

A failed head gasket will usually result in persistant bubbles in the coolant, along with an oily scum. Water in the oil looks like coffee with cream on the dipstick (don't drink it though, lol).

As far as the CODE 15 goes, it's just telling you that the sensor circuit is inoperative. Hit the local GM(saturn friendly) dealership, and get a new sensor and connector both. Will cost you about $40usd

i've replaced the sensor already..but not the connector. i'll try that and see what happens.

i checked the oil...it looks fine. had an oil change as part of the tune up (jiffy lube)

check for leaves or trash or mouse nest between the condensor and the radiator.