View Full Version : 94 prostar 190 thermostat

11-06-2011, 11:13 PM
I have a 94 prostar 190 with the corvette engine. I would like to change out the thermostat to a higher degree, I believe it has the 140 in it and I would like to go to a 160 or 180 to get some more heat for winter skiing. I recall hearing at one time that the corvette engine has two thermostats, can anyone confirm or deny this? Im thinking it only has one myself, but I want to be sure,,,, thanks for any info

11-06-2011, 11:26 PM
I believe it has 2, a 140 and a 160. You should not change either to a hotter t-stat as it will make the ecm go into limp home mode.
If you want more heat I think skidim sells a y-pipe fitting that would gain you more hot water to your heater.

11-07-2011, 03:06 AM
It does have two - lower is 140, upper is 160 - special drilled marine version. My LT1 always runs around 170ish by my temp gauge.

11-07-2011, 01:53 PM
The lower thermostat, the 140 degree, is there to pre-warm the incoming water, so that bit isn't too cold when it hits the aluminum heads.

The upper thermostat, 160 degree drilled thermostat, regulates the temperature of the block.

If the upper t-stat has been removed and is missing, it was probably removed due to overheating.

Make sure that the following mod has been completed for your engine:


11-08-2011, 02:11 PM
My engine never gets above 140, and when at idle 120. maybe the top thermostat is not there. Thanks for all the good info

11-09-2011, 06:57 PM
I will just about guarantee that the top thermostat is either not there, or it is stuck open.

If it isn't there...it was likely removed to resolve an overheat problem...this is not the correct solution. see the link that I provided earlier.

11-09-2011, 07:52 PM
Jorski,, Im going to definately check into it and I may be in contact for questions,, Thanks Frank