Ok so what do I need to do to re-program my computer to run with my 160 thermostat? I'm not having a problem with overheating I just want the fans to turn on before 230. Went to the local GM dealership and they said they "can't" do it.

 

you can do one of several different things...by far the easiest and most painless is to get an aftermarket chip, such as a jet 2 or a hypertech thermomaster and slap it in your ecm...next option is to have someone with the equipment and software reprogram your existing prom to do the same thing...next I believe that some company(s) make an temp sensor that fakes the computer into beleiving that the coolant temp is higher than it really is, thus making it turn the fan on earlier....the next option after that is to install a manual switch and turn it on and off whenever you want.

 

You got good advice from the dealer, DON'T run a 160. The engine runs best at 195 and it's no joke. I have posted many times about this and this is the straight "poop". Every engineer in any company I have discussed this with is in total agreement. The engine runs best at it's designed operating temp. If you fool around with different stats(I have done it)all you do is screw around with the driveability of the car. I put 3k/yr on my 89 350-all stock and last week took it on a trip 171 miles/7 gal of gas. All of the crap you see here and other places about colder engine temp is just that-CRAP. Current engineering into more efficient engine management is looking into higher engine temps. Look at it this way, just about EVERY engine in the last 20 years runs at 195(even my new sportbike-130HP 998cc) so the engineers know a lot more about internal combustion than anyone here. And despite what you hear it's not just about emissions. Fact is that lower emissions=better efficiency=performance. If you must run a lower stat go with a 180, depending on driving habits you will probably not notice any significant difference.

 

they said nothing about performance. they just want lower temps.. and fact is, that u may have a 195* therm. but ur fans wont turn on to 210+. so ur gonna be running between 215-225*. and i know for a fact that my car is stronger at 180* then at 220.. and when you have lower engine temps. ur gonna have lower air intake temps. lower engine\MAT temps will give you less spark nock and more dense air. and everyone knows that less spark knock (especialy!!!!) and more dense air = performance.... those extra 20* make a big difference. id rather be running slightly rich then slightly lean..

 

I agree with both danno and breathment to a point

The #1 reason I run my car with a 160 stat and 160 fan turn on is I live in central florida...brutal traffic..100 degree plus ambient heat...in the summer with the cooling system in good shape, airdam in place, good coolant mix etc etc the car will run 220 even with the lower temps...before I lowered the fan temp (stock temp was set at 232, according to the snap-on scanner) the car would hit 240 in short order in traffic and the fan had a very hard time pulling it down once it hit that high, I didnt like driving on the ragged edge of cooling. I did it to survive the florida summers.

 

IIRC my dads 2002 suburban runs <195
IIRC my moms 2003 cavalier runs <195

so......

 

The 160 thermostat wont help the problem with overheating, if the system is not up to the job. If the temperatures keep going up, you need more cooling, not a lower thermostat setting. The older systems don't have enough cooling to cope with slow traffic, high ambients, A/C on and the transmission in drive while stationary - according to the works manual.

I think the original system was designed for manual transmission, which does not require engine power while stationary. The automatic transmission uses loads of power and heats up an engine when stationary.

Lower temperatures and rich mixtures will cause more problems with cylinder lubrication than anything else other than no lube or real overheating. You also loose power and it can delay the pick up from low revs. You don't want that or you could get smoked by a Mustang.

One big problem though, is the standard temperature and pressure guages are not reliable or anywhere near accurate. If you were to fit mechanical pressure guage and temperature guage into one of the heads you will likely see totally different temperatures and pressures.

You should make cooling change decissions only on accurate temperature indications.

Oil temperature is also important. If the oil is under temperature it will get too thick and use more power, which turns into heat and reheats the engine. The whole temperature, fuul ration. oil viscosity thing is a major balancing act for the engine designer.

If the oil is too hot you can damage the engine. It sounds like you might want just a little more cooling capacity so an oil cooler might be worth thinking about in Florida.

 

I've thought about the oil cooler before, and one of these days I will hook one up Just gotta have the extra cash in hand.

I agree with all you are saying too. With the fan coming on at lower temps and quicker coolant flow from the lower stat, it does make about a 20 degree difference in summer operating temps. I think if I was in an area where the ambient temps arent as nasty as they are here I would run a 180 or 195 stat and see if I couldnt get my fan temp about 200 210....that would put me in the right operating range and still give a better margin than a 230+ fan temp

 

You don't need an oil cooler if you switch to a synthetic lube. The reason Chevy made Mobil1 a factory fill is that they dumped the oil cooler on the Corvette and found that by using synthetic oil because of it's enhanced characteristics they did not have to worry about excessive consumption especially with the 5-30wt which they prefer to use.

 

yeah I'm going to be switching to full synthetic soon...be interesting to see what kind of temperature differences I see

 

I usually pass on these temp. things because I know about opinions. However, I do know that as an engineer working for one of the largest chemical companies in the world I'd be ripped by the boss if I designed, or allowed to operate, a process where the temperature flunctuated 35 to 40F and rarely stayed within 2 or 3 degrees of the control setpoint (195F +/- 3F). I've got 2 IROCs, an 81Z and I just gave my 83Z to my oldest son. Of those 4 Z's the only one that has a cooling system operating in control (all the time, not just in the winter) is the 81Z. Man, those HOT engine temps. mean HOT radiator temps. Those hot radiator temps. can't be good for the transmission fluid, the oil or the rest of the engine. It appears GM can get away with designing a temp. control system like this (plenty of us bought the cars anyway the engine and auto tranny usually lasts past the end of the warranty, doesn't it?). I also know the later systems do a much better job of controlling temps. My S10 Blazer and Jeep Cherokee Sport do have cooling systems that control the engine temps. within a couple/three degrees of the thermostat. I know, another opinion. Sorry, engine temps. on my IROCs is one of my peeves. Have a good one.

 

I also have other GM vehicles. My Blazer maintains a more stable temp because it has a clutch driven fan. It was not a design error so much as necessity with the way the Camaro's with electric fans behaved. To maintain a constant operating temp like a clutched fan would require the electric fans to be cycling constantly. Allowing the engine to reach 220deg. before fan turn on is necessary to keep from chewing up alternators once a year and also extends the life of the DC motors in the fans. A 25deg. spread is actually pretty realistic and does not really pose a problem with a well maintained cooling system. From an engineering standpoint it was actually pretty well designed considering we are dealing with a vehicle with really no front grille to speak of. Most cars with electric cooling fans allow a 20 or so deg spread, my daughters cavve is like that. As far as the engine/trans service life issue I would beg to differ. I know very few Chevy smallblocks failing after the warranty term, ditto for the AT's. Early 700's had issues but they were not so much cooling related as they were design problems. You mention design work, I have given it a lot of thought also and basically the guy's who did the design came up with the best compromise given the overall set of circumstances they had to work with. I have tried all different setups and I went back to the stock operation. It actually results in the best overall operation while not placing undue stress on any one engine component.

 

Some of those new car temperature gauges, are not actually telling you the real engine temperature. The temperatures do fluctuate just as much as before, but the new systems lie to the drivers, to stop them worrying about the temperature.

Also some of the sensors are not in the coolant, but the metal of the cylinder heads.

What happens is there is a range where the engine is OK, so the computre tells the guage to show a nice temperature, like just to left of centre on the guage. No one worries when the needle is to the left.

If the engine metal should get above the set point, then the computer tells the guage to make the driver worry, by moving it over to the right of centre.

If the engine really starts to overheat, the computer tells the guage to scare the pants off the driver and move right over to the right. In some cases the computer starts to shed loads, by cutting out half the cylinders, and changing into the get home emergency mode.

All engine temperatures vary with load, from the car ngine to the gas turbine. The higher the temperature the higher the efficiency, te limit is the materails melting, softening or expanding too much. That is why ceramics are so good in engines.

 

PS if you fit a proper sensor to one of the new cars, and measure the coolant temperature, you see it act just like on the old cars.

 

stock 350 tpi thirdgen, 195 thermostat, stock dual fan setup..

i run about 220 fully warmed up.. even when i turn my passengers fan on earlier it just keeps the temp from increasing which is what i wanted... brings it down just a tad sometimes...

 

The fan motor can't be that hard on the alternator. The 83Z has an adjustable switch installed, but adjusted so that the fan stays on whenever the ignition switch is in the on position, and the alternator just hit 4 years of hard use (my oldest son was 17 when he started driving it and believe me, he complains about 14 mpg because the only thing that keeps his right foot from hitting the floor everytime the stoplight turns green is the gas pedal) in August. I'm not happy about the temps varying like they do, I wouldn't be happy about the oil pressure varying (at a constant engine speed), I wouldn't be happy about the rpms varying (at a constant vehicle speed) I wouldn't be happy about the alternator output cycling up and down at a constant engine speed. You wouldn't be happy if your gas mileage and horsepower varied as you drove it down the road. Everybody is different. I don't like something that could be controlled better being set up with a 195 degree thermostat and a switch at 230 degrees. Evidently there's a pretty good market out there for switches that turn the fan on at lower temps. I like my IROC. I'm going to hate to give the black one to my youngest son in a couple of years. I just don't like the temp. varying like it does.

 

You might want to check over the cooling forum a couple of months or so. A guy here got a clutched fan from a different model GM, he says it fits and works pretty well. I looked at my 89, just does not seem to be any room for a fan. The fan motor by the way can pull anywhere from 10-15 amps at start up and I have TWO.

 

I really hate electric fans. They need the alternator, the battery, the computer, the eletric motor, a temperature sensor, lots of wiring, a fuse and the fan belts to all keep working. And they need the driver to get used to the engine termperature wandring around. And they don't blow any air over the engine components. Also if they keep turning in the wind, nearly as fast as when they are powered - just how much energy are they really saving if any. Some one will tell me I guess.

The regular fan just needs a fan belt and the internal clutch. Less to go wrong, except you can't wear a tie and open the hood at the same time.

Phew I feel much better now I got that out

 

I agree, and if I could fit a clutched fan I would do it. There is a guy on the board that posted you could fit a fan from a caprice into a TG. There is no way I could do it without rerouting the air duct and relocating the MAF. Some guys here say the electric fan because it rotates faster winds up being more efficient but I would as was said here like to have a stable operating temp.