hey i am new here and i just picked up a 85 trans am and changed out a few things already but lets get to my question what is the lowest thermostat everyone is running here? i am running a 160 degree. is that too low?? do i have to do anything else besides just changing out the thermostat? thanks Jason.

 

180 is the lowest you should run without reflashing the ECM.

The reason behind this is the computer does not go into closed loop (Begin making adjustments based mainly on the O2 sensor) until a certain temp.

Some people have ran the 160 without a tune fine and others have had problems.

 

what kind of problems were experienced? and i dont think i have a 02 sensor........ i think. lol

 

i ran a 190 in my truck which is carb'd not fuel injected and it stayed at 190, 205 max. i added air conditioning and saw it climbing to 220 which in my opinion is too hot. so i put a 160 in it.
the effects it had were:
1. takes longer to heat up
2. doesn't blow my heater as hot
3. runs cooler

so it's great in the summer with ac but not so good in winter.

in my camaro i went with a 180 which is less than stock. i have fuel injection there, and no ac. it stays around 190. it doens't take too long to warm up (5-8 mins) but blows my heater a little colder than i'd like. the engine doens't seem consistent with the idle quality, it's good 1 seconds and bad the next... with alot of mods like hsr, cam, heated o2 sensor, aluminum heads, no egr/cat/smog, aluminum 3 inch radiator and dual electric fans. its just too hard to say what's the source of the inconsistent idle. i may swap to a hotter thermostat though to benefit with the heater. i know 3rd gen camaros are meant to run around 200, even up to 240 without problems. if i were you i'd use a 180-190 thermostat.

of course, you don't know what your temp is with the stock gauge, you need a more accurate aftermarket one.

 

cast iron heads - 180 stat
aluminum heads - 195 stat

btw the coolant temperature is not the only thing that makes for closed loop operation, and if it was, the variable is set in the low 100's so it goes to closed loop no matter what temp stat you run, unless theres some other problem.

 

I run a 180 in the summer and no thermostat at all during the summer, and I haven't had problems yet. Summer, car stays 175-190ish and winter is 190-205ish. Hope that helps.

 

i ran a 160 in mine and now the heater dont blow at all so im goin back to a 180 cause im pretty sure the stats messin it up.

 

What compelled you to install a 160'F thermostat?

 

I've got a 160* stat and a Hypertech cooling fan switch, and it does go into closed loop!(laptop prom proven/data master)

 

Try running a 170 degree thermostat. I will check to see if I can find the part number they were used in some GM cars. I got mine from the Chevy dealer and think it was around 15.00 Bucks works great in the winter and summer

 

i am not going to drive the car during the spring/ fall/ or winter. its only going to be driven when i feel like driving in the summer between that and a jeep, and a couple bikes, lol. and i said 160 insead of 180 lol. ah well lets see how it goes. lol

 

160 is fine to run and that's what I use. Durability is priority, because I invested a lot in my engine and I want it to last a long time.

 

I've run 160° and 180° thermostats. My car seems to like the 180° stat the best.

 

In a sence, I'm in the same situation here.....I had both the T-stat and Fan Cooling switch STOCK on my car(190* stat and 220 On/200 Off switch). I then switch them both at the same time too 160* stat and Hypertech cooling switch #4026.....NO Problems!

I would like to try a 180 stat and hyper. #4028 and see how my car runs at these settings. There have been many threads on cooling and just as many opinions on what SHOULD BE USED!!!!!

I feel/believe that some cars SEEM to run a little better cooler(160*-180*) then another running warmer at (180*-210*)......And visversa hold true too, some cars seem to run better. (Ex. they both could be 350 TPI's, one will run better with 160* and the other runs better at 180*-200*)

My advice to you is play around with your car and see what feels right for YOUR car.......But I would NOT go any lower then 160*!!!!!! I'm willing to try 180*

sorry 4 the rant!

 

Cylinder bores ware slower when engines are run hotter.

 

agreed. i was waiting for someone to post that picture of the cylinder wear test vs. coolant temp. but here it is.

 

Cool you found a chart. I read it in books before any one really had home internet.
It looked a lot like that but the one I remember seeing the most was a chart that did 50,000 mile tests with 140, 150, 160, 170, 185, 195 and 210 degree thermos. The hotter the engine the less the bores wore.

I run a 195 degree thermostat year round, according to the temp gauge (which I believe reads hotter than it really is) reads about 190 or so in winter and 220 in summer.

 

Nice flow chart! That's another reason why I would like to up my temp!

Note: My current set up has the car running at 176*- 180*ish.... So according to the chart, not too bad! But yes, the wear could be better.

Time to start playing around I guess. Proformance VS. Wear (finding the perfect balence!)

 

That's what I run and I like it. Works great for summer and winter. Summertime, the fan will be on the majority of the time, but not all the time. Once you're cruising, the fans will probably be off.

In the winter, the fans only come on as needed. Heat output is still good.

I say why have lower volts running both fans when not needed?

 

if you look closely at the chart you can see that from 175* to 185* the wear is almost cut in half