onefast99

Thanks for the responses, the former owner put a 160 in the car not a 180 I just changed the t-stat today to a 180. I noticed the gasket on the new t-stat isn't as thick as the one on the 160 was, do I need to put any type of mr gasket on the housing?

richauto

I agree with mazdaverx7

enventr

I have a stock 180 in my LT1 and Dewitt's radiator and still on hwy it runs 200 - 203 but cools down faster and climbs up slower(3.07 rear)

Tom400CFI

Something seems amiss there. With that massive radiator, you should be down "agains the T-stat" most of the time. As mentioned earlier, mine runs cooler than that and I have the stock/original radiator.

enventr

Maybe my 3.07 rear revs higher than the 2.59 stock creating a slight increase in temp.

Tom400CFI

Maybe...but I have a 3.45 in my car.

Netfly

When you come off the highway and idle or go slow does it cool down?

Netfly

I like to use Permatex High Tack on the gasket.

STL94LT1

No sealant is required for an LT1 thermostat, rubber gasket on the t-stat does the sealing.

WW7

When I had the Stewart racing thermostat in my 89 , on cool mornings with temps in the 60s, on the highway, my engine temp would get down to 160-165 degrees which I considered to low....I had to put a "Stant super stat" in to control my temps better... The 180 degree super stat I have in now won't let my temps get below 175, as soon as the temp gets down to 175 the stat partially closes which causes the temps to rise to 180 degrees again.The "Super Stat" is the only thermostat I know of that controls your temps within such a tight range.Alot of other stats will let your temps go way lower before they close again....So on cold days with a 160 degree stat your engine temps "will" be lower then with a 180 degree stat, on hot days the engine will run up to whatever temps your cooling system will allow....WW

enventr

Sometimes driving locally temps will be 195 that is without stopping for red lights which does elevate temps. I also forgot to mention that I have a small staked plate trans cooler mounted about an inch away from a/c condenser.I know by reprogramming fans and adding a 160 stat will make it cooler but I want to keep it close to stock.I also believe the "big mouth" air dam would increase the airflow making it cooler but I do not like the looks of it

WW7

The most efficient means of controlling your temps is to use a lower thermostat along with changing you fan settings.. When I installed the 383 in my car the tuner had me install a 180 degree stat and programmed my fans to come on at 190 and off at 180..This kept my upper temps within a ten degree range, then he tuned my car for those tempertures...If you want to keep your temps close to stock leave the car like it is, don't change anything, these cars have been run for years just like they are without damage.........WW

Netfly

So its elevated in temp around town too. May be worth trying a new EGR. I hate throwing parts at a problem, but if it hasn't been changed it may be time. It wasn't that expensive or hard to do on a L98. That said, I don't know the LT1 that well. So there may be other factors involved.

Tom400CFI

Me too. TEST, before throwing parts. An EGR is a very easy part to test.

That being said, I have not seen bad EGR's causing high operating temps. The EGR lowers combustion temps when open, has no effect when closed.

Netfly

I didn't know any test to tell me it was stuck half open other than looking at it and once it was out it wasn't worth not changing on a 22 year old car. Any yes it was the cause on my L98. See my post above. Its recirciulating exhaust into the motor, thats hot. Its adding more heat into the motor.