I need a 180 degree t-stat for my '94 Sl 2 but can only find 188-195 units on any parts catalog . Who knows what brand and part number 180 degree piece will fit in this engine (1.9 dohc finj) cooling system performance is fine under nearly all conditions . But I live in a mountainous region with long inclines on the interstate . Climbing these long grades with A/C on , maintaining 75-80 mph causes the engine to move into the caution part of the temp gauge . I had the identical issue with my 97 Sl that was cured by downgrading the t-stat . My car is 100% reliable and I do not like the idea of running it near maximum op temperatures HELP ! I really need to source the correct fitting 180 degree t-stat for this engine .

 

I find it hard to believe that your thermostat beginning to open 5 degrees sooner has anything to do with the temperature at which the engine runs under extended heavy load.

The cooling capacity for the vehicle is a function of the volume of coolant, the effective thermal transfer properties of your coolant (which will decrease with time), the speed at which the coolant is circulating, , the efficiency with which the radiator dissipates heat, and external contributors like airflow across the radiator, either from driving or from the cooling fan.

I would highly recommend installation of a manual switch for the under the hood fan. This should allow you to run at lower temperature all the time instead of waiting for the ects to indicate 222 and turn on the fan. Of course, I do not know if your fan is already running and you are hitting these high temps with the fan on......

Did you ever replace the original ects with the newer brass design?

If yes, then I would say that the way to keep your operating temps down would be to optimize all aspects of your cooling system. A thermostat that opens 5 degrees sooner is not relevant once the operating temps get that high. It is open all the time under your stated driving conditions.

Remember, the temp guage is not linear. Maybe you could borrow an obd I scanner w real time data readout and determine what temp you are running at.

Suffice it to say, you are pushing your satty close to the limits of what it can do. The car was designed as a cheap commuter car. Conditions like yours were probably used to define the limits.

The only other thing I can think of is adding additional cooling capacity to the car....have to think about how... external oil cooler??

 

Well Mr. Derf ,
When yer right , yer right . after determining NOBODY manufactures a 180 tstat for these 91-94 Sl2 DOHC engines . I was forced to conform to the status quo and installed the recommended 188 degree unit , a new brass probe ECTS , and genuine AC Delco coolant reservoir cap . And voila , operating temps though not substantially lower , are now more stable with cooling fan activation considerably earlier preventing temps from climbing into the "oh-no' zone . Appreciate the insights . While performing the needed cooling sys maintenance I also discovered a badly decayed EGR hose which was having a severe impact on my otherwise excellent fuel economy . Thanks again

 

If you want to increase your mileage some more (likely), remove n clean your EGR with choke cleaner until the pintle moves up and down and rotates freely. Its movement is likely restricted if you have had a vacuum leak and the EGR has not been moving its full range. It takes a lot on an OBD I S car to throw an EGR code (42?) so you don't know it is happening until it gets bad enough to cause problems, usually on deceleration.

MAKE SURE YOU HAVE A SPARE EGR GASKET THAT FITS YOUR VEHICLE BEFORE ATTEMPTING, in case the .gasket in there tears/doesn't seal when you are all done.

Remove the EGR valve. Keep filing it and soaking it with carb/choke cleaner until the pintle moves freely. DO NOT BEND THE PINTLE or it is done for.

The second half of the exercise is fun, loud, and can get messy if you are not careful.

The passages that lead to and from the EGR valve are likely full of carbon deposits. The passages are large, but the deposits on the one leading to the EGRvwill find their way into the EGR eventually or promote easier buildup in the EGR..

With the engine warm but off, and the EGR valve off, spray a good amount of choke/carb cleaner into each of the two passages with the goal of rinsing down the walls. Let it sit for 1-2 min. While doing so, rig up an absorbent cover to catch the wet brown sludge that will be hurled out of the tube that feeds the EGR. The force of the exhaust straight out of the engine will send the sludge barreling into the air at high velocity in a generally forward but random direction. if you don't try to catch the gunk, you'll be cleaning your entire underhood area, the underside of the hood, and whatever is directly in front of the vehicle. You have been warned.

It is LOUD. RAW EXHAUST. WEAR HEARING PROTECTION.

Start the engine (may be a bit difficult), you may need to pedal it. The idle will be way high as you have a massive vac leak from the port coming out of the EGR going to the intake. Let it run for literally 3 sec, then shut off and repeat. Most of the slime is expelled when the engine starts and the first blast of exhaust hits the dissolved carbon goo.

This is an iterative but rewarding process. You will never get all of it, but if you can get the ejection of sludge to kind of level off with each treatment, you've done enough. The first 2 or three will be a mess. then not so much.

Do not try to hold something over the port that ejects the sludge. The exhaust gas is HOT and you may get burned. Not worth it.

if you choose to do this, please check back and post how much fun it was.

 

 

I actually do my egr cleaning midday with the garage door down (I work from home). I figure it annoys the fewest neighbors in the development.

I would like to know how far away it can be heard with the garage door up........

 

There's only one way you're going to find out, derf. LMAO