My 95 Formula LT1 temp. is acting crazy. I installed 160 stat and by-passed TB last week. 4 days later eng. temp. went past 210 almost to next line on gauge, AC compressor quit at same time. Compressor was bad, changed it, it ran about a day, now clutch won't pull-in, both fans turn on though. Eng. temp will barely read between 160 and next line up even on 95 degree day idling. I can't find any thing wrong, anybody got any idea of whats happening. Danny Mc

 

temp sender going bad?

Also is it an LT1 Thermostat. I forget what the difference is, but LT1 Thermostats have something different abotu them.

Also a dumb thing that I have done once, I put a thermo in upside down in a car some years back.

Another one...did you bleed the lines when you did the Bypass and Thermo?

 

Did you tune the car for the 160* stat? Check to see if it is installed right, it may be stuck open.

 

No tune is needed when installing a 160° thermostat.

 

Yeah the only thing they can tune is to have the fans come on sooner witch is a good idea but you can get a fan switch for that.

 

I bleed air from system several times, got very little out. I did quick change on stat, and bypass since TB was out. Stat was Hypertech 160, put in correctly. I took the tune program from my 94 Camaro LT1 put in 95 Formula LT1, it never showed any prob. with same settings. I can't figure out why it got so hot once but not again, Camaro temp. always ran about one width of pointer above second mark on gauge. Can't figure out why AC won't turn on. BTW the gas hoses are hell to hook up in the tight space behind compressor no damn room to work. any one? Danny Mc

 

oh ok, I thought you had to get one when you installed a 160* stat, or maybe that's just us '93 guys, or it could just be because I did it when I changed everything else around on my car.

 

You've probably already done this, but verify that you aren't throwing any codes.

Hook up a manifold gauge set and check your R134a pressure...

as for what temp that water temp gauge shows on one car vs the other, it could be just the different gauges or a sending unit... If you have freescan or something like it, verify that the coolant temp reading is showing the same from the pcm as it is on the gauge or at least close...

I don't know if there are any differences in the 95 v 94 pcm that would cause a problem sharing a program...

 

Ok, so what's the problem? Just that the AC compressor clutch won't engage? Or that the car went to 210* one time? If you installed a 160* thermostat, a temperature reading of ~170* is normal. Did you check to make sure everything was hooked back up correctly to the compressor? Did you charge the system? The clutch won't engage if you don't have the system charged enough.

 

Guess I confused the issue by mentioning 2 things. (1) I can't see why eng. showed hot only 1 time and AC quit at same time, just a coincidence I guess. Temp. gauge diff. probably normal. (2) Why won't compressor start. I changed compressor and dryer, added 4oz proper oil to compressor and to dryer, pumped sys. down, added 2lb's 134a, compressor ran for awhile, didn't cool too good, now clutch won't pull in. AC Coil checks good. WTF is wrong. Danny Mc

 

It didn't leak all the refrigerant back out did it?

 

I'd double check your refrigerant pressure.

Also scan the pcm to see if you're trowing a code... Code 61 is a common one that will prevent the compressor clutch from engaging and it won't light the SES light...

 

Pumped AC sys. down again, added 2lb. 134a, checked reference volts (ok) swapped low presser sensor, still no signal to compressor, fans start when AC turned on. Will scan today for 61 code, since no ses light. Thanks for info. Danny Mc

 

I'd bet the temp got to 210 ONCE because there was an air pocket in the cooling system that has since worked itself out.

 

I took - batt. cable off for 10min., reconnected, then compressor started at last, cools not great but much easier to check sys. with compressor running. No more spikes in eng. cooling sys. temp. Thanks for all the info and interest from you guys. Danny Mc