hey guys, last week i noticed my temp gauge sky rocket, so i opened the hood and noticed a crack in my radiator. so i replaced it with a stock replacement from ac delco. before installing it, i flushed the old coolant out of the block, and put about a 70/30 mix of water/antifreez in. when i started my car, the temp gauge sky rocketed again! i was really confuzed, but figured it might be the thermostat. so i replaced it with one from advance auto, a 180 degree. now everything works great, except it runs at 140 degrees constantly, never going a degree higher?? i know this isnt normal, does anyone have any ideas why? and is it harmfull to run so much below the intended running temp? thanks in advance

 

Did you buy the correct (and oddball) thermostat for a "reverse cooled" LT1 engine?

http://shbox.com/1/tstat.jpg

Did you install it facing in the correct direction?

You don't want to run at 140degF.... in some cases the PCM will not go into closed loop at that temperature.

 

Yeah, installed the correct thermostat in the proper position. Its weird. You can watch the temp gauge climb, but when the thermostat opens at 180 or whatever, the gauage will drop to 140. I dont understand...

 

anyone

 

140? my dead bottom tick is 160 so how r u getting that #? also if your car warms up to 180 there is NO WAY it is cooling to 140 while driving...mine sticks around first tick and a little above...180-190

 

'93 guages are different.

I am not sure how your car can run at 140* with a 180 thermo. Is it closing all the way?

 

i had a 160 in my TA but it ran too cold, like 170-175 all the time so i put my 180 back in. with the 180 i stay around the first tick which is exactly 195 degrees.

 

first tick is 185...
160.....210(half)...260(dead boiling)

plus i think all gauges read a little high..

 

i dont wanna argue with you dude but the first tick is 195, i have a scanner and i checked the exact temp when i was at the first tick.

 

maybe i just cant read the gauge properly. ill take a pic of it and post it. thanks for the replys so far

 

95white----im not trying to argue...if u can add and do simple math first tick SHOULD be 185(according to the gauge)..but as u said urs is 195 at first tick so ur gauge is off...mine reads at first tick and that should be 185 but my scanner says its 178

 

The scanner isn't reading the same temperature sensor as the gauge uses, so you can't really check the one in the head with a scanner. The coolant temps at the two sensor locations aren't even necessarily the same.

And that's something to keep in mind. Everyone assumes that since the 93 gauge starts with 100degF, they can just linearly interpolate between the bottom mark and the next mark. I doubt that's the case... I think they just mismarked the 93's and then changed the markings from 93 to the later model, and kept the gauge the same.... who knows.

93z96svt:

Rather than guess how to interpret the hashmarks on the gauge, get a scanner on the ECM and check the actual operating temperature, at least as the sensor in the water pump sees it.... you may not have the problem you think you have.

 

my scanner gives me the coolant temp, which may not be exactly the same as the engine temp.

 

but while watching the scanner, the temp increases at the same time as the gauge so that's either a huge coinsidence or they are the same.

 

what i do is...since i have my low fan programmed at 180 i pop the hood and when the gauge reaches a tad over the 1/4 tick (which should be like 185-90-95)(according to the gauge) the fan kicks on so this is how i know my gauge is off by 5-10 degrees...the engine coolant actually runs 5-10 degrees colder than the gauge says. my tach is also off by 100.