LT1 running too hot...?

[Josh '95 Z28 A4]

I have a 160 degree thermostat and I have reprogrammed the fans with my HPP3 and today when I was driving on the freeway, it would warm up to the 210-230 degree range. I thought it would run cooler with the 160 degree thermostat because I know with the stock 180 degree thermostat it was normal for it to get that hot. Also, I have a 3.42:1 rear end gear ratio w/ an A4 so at around 70-80 mph, it runs in the 2500-3000 rpm range. So would that make it normal or is it too hot? By the way, I know me having the A/C on for a little awhile contributed to the engine warming up as much as it did, but usually when I get on the freeway with it off the engine gets up to about the 210-220 degree range anyway.

[Hip_about_time]

Might want to check your radiator to see if it is flowing freely, my '95 was doing the same thing and after repalcing every thing else I found my radiator was blocked up

[Joe 1320]

Is this a modification you just performed? If so, the f-body cooling system requires that trapped air be bled from the system whenever it has been opened up. The two bleed screws are located on top of the thermostat housing and the return line. They are both fairly close to each other. start the car and as the temps rise, open the bleed screws to release trapped air until you get nothing but liquid. Be sure to have a few towels on hand to prevent fluids from leaking down to your optispark.

[Joe K. 99 Zeee!!]

If you go more than the recommended 60,000 without getting a coolent flush, the coolent will beging to gunk up your system. Mine gunked up the low coolent sensor and the heater box.

If you've already bled the system and flushed coolent then test the thermo in a pan of boiling water to make sure it's opening at the correct temp.

Another thing....did you install an LT1 specific thermostat? It must be compatible with the reverse cooling system.


I have the 3.42's and 160 and I run between 178-185 on the warmer days going down the highway at 65-70mph.