95 Saturn SL2 overheat?
 

I have a 95 Staurn SL2 with 183,000 miles on chasis and little over 4,000 miles on newly rebuilt motor, however I have noticed it runs great and stays cool while moving, but seems to heat up while stoped at light and such. I believe the fan is not working, is their anythig I should look for that would cuase it to not run? Bad Sensor? Bad Fan Motor? What should I do?

Thanks guys!!

When you are moving,air flows through the radiator and cools the coolant. When you are stopped the air flow stops. If you sit still long enough, the coolant temp. will increase till it gets to about 3/4 scale at which time the fan should come on. If you think the fan is not coming on, turn the AC on. If the compressor kicks on but the fan does not, then you do have a fan problem. Try this, repost, and we will then diagnose further. I believe 95 models had 2 ECTS's-one for the fan and one for the gauge. 96 and up got by with 1.

indeed 95 was the last year for 2 temp sensors.....

the 3/4 tick mark on the temp gauge that hoseppi mentioned is the key -- if the fan turns on at this point, all is well. You didn't mention any actual overheating....

If the fan does not turn on with the A/C clutch, it could be the fuse for the aux cooling fan, the cooling fan relay, the fan itself, or a defective ECTS -- but hoseppi will lead you through the troubleshooting.....

No it's not actually getting to to that point of over heating, I was nervous about letting it get to that point. seems 3/4 mark is alittle high, but I will let it go and see what happens, and i will check it with the A/C running.

Thanks Guys!

3/4 mark is standard behavior for S cars -- the gauge response is not linear.....I would definitely recommend the A/C check for the fan with a cold engine, as the fan is designed to come on with the A?C. If the fan doesn't come on then there is definitely a problem we need to address to prevent true overheating, which is bad for these aluminum engines (head warpage, etc)...

oh -- did you change out or rebuild the water pump when you swapped engines?

hi guys question about this topic. Im new to these cars. Just picked this 97 sl2 up for a daily beater. Had a blown head gasket and bad temp sensor/connector. I fixed these already. New prob is why did the temp get a little past half way and I hear puff, and my coolant tank had a small hole in the side of it. To much pressure?

fan works: if i disconnect the temp sensor the fan goes on. so relay and fuse are good.

thermostat is new, as is radiator, water pump is good.

im seeing on the thread that the gauge goes 3/4 way... i was scared to let it go that far. i figured the coolant tank blew because of the heat being over half way.

Ummm

Never heard of an S car coolant reservoir tank exploding --- now I have.

I have a 95 and 97 Sc2 (both single owner -- me). When the temp gauge goes to 3/4 tick, the aux cooling fan comes on, it cools to 1/2 way between 1st and 1/2 tick. This is normal behavior on an s car.

Maybe too much pressure (maybe "restriction" in a cooling pasaage or hose somewhere), maybe the res tank itself has become brittle since it left the factory 13 yrs ago.

What was the consistency of the liquid in the reservoir? Orangeish coolant or milkshaky?

Which temp thermostat did you install?

I have an idea on this topic for you, it somewhat goes along with what derf was saying. Since 1996, General Motors has been installing an orange coolant called Dex-Cool in all of their vehicles. Unfortunately, Dex-Cool will eat through the inside of the radiator, and the hoses. This will cause an orange sludge to build up inside all parts of your cooling system, which can cause blockages, which can lead to blown head gaskets for one. A friend of mine who is a mechanic( and who told me about "Dex-Kill") saw a 2003 Chevy Malibu blow a coolant hose, then a tank, then a heater core, before it blew the head gasket. Now this was also due to the fact that some genius dumped two cans of Bars-leak into the coolant tank... Anyway, I have switched my 99 SL over to the green 50/50 stuff. I would advise all others do the same. Don't just take my word for it though, a few states have filed class-action law suits against GM for Dex-Cool related component failures.

interesting -- what does GM use in new cars these days?

not sure which thermostat I bought, I went to autozone and bought the OEM rated one. Usually I pay attention to these things.

coolant is green 50/50, it was already green when I got the car.

just picked up a overflow tank at the junk yard. Must be fairly new as its still white. Hope this solves the prob

when the head gasket blew the water came outside and so the motor never had any water inside.

well ill know shortly if this was the prob... wish me luck.