What's reverse cooling? LT1s are reverse cooled, as opposed to say L98s. What other GM vehicles, and engines have reverse cooling

 

Reverse cooling means that the LT1 pumps water from the radiator to the heads first. Most engines circulate the water through the block and then to the heads. This reverse cooling allowed GM to be more agressive with the timing/compression of the LT1 motor and keep it out of detonation by keeping the heads cooler.

You can find a good write-up here:http://www.theherd.com/articles/lt1_cool.html

 

Not changing your coolant regularly will do that

 

then ya got a bum waterpump, mine afaik made it 150k miles, I only changed it because i was changing everything else, the bearing was just a little shot but it wasnt leaking, btw did your bearing fail or did it start leaking out the weep hole?
The cam driven waterpump is only supposed to make the bearing last longer, not the seal

 

my car water pump went out at 65,000 miles , but i was a 1994 , raditor was flushed twice at 25,000 and at 50,000 . and the bearings were mising and rusted and seals where shot and was pissis out the wep hole oringal wp . in 2003 . so it lasted 65,000 mils and 9 years , i think thats preety good . plus it was cheap to fix .

 

Bearings missing == bum water pump (In the eyes of the engineers who designed it), the cam driven water pump decision was made because it was supposed to put less load on the water pump bearings. the seal being shot is evidence of poorly maintained cooling system although once again if its a bum water pump the seal can go prematurely, 65,000 miles is a lot of miles for a water pump, but they were supposed to last more than 100k...

 

Waterpumps are a common failure on the LT1 so it's obvious they have more issues than the bearing load. Also the cars came with Dexcool from the factory that was supposed to be good for 100K miles.

 

Mine didn't come with dexcool from the factory.

 

It's possible that Dexcool didn't start until 1995, but still waterpumps are common failures with the 95 - 97 crowd.

 

Reverse cooling is awesome. End of discussion.

 

I have an early 1995, built in August 1994 and came with Dexcool.

 

I have had 3 LT1 cars; a 94 Z28, a 95 Z28 (bought new-built in December of 1994, had conventional coolant), and my 97 SS (bought used, with 9k miles). The 94 and 95 both went well over 100k with no problems with water pumps; the SS lost its first water pump (badly leaking out weep hole both times) at 38k, the second at about 67k. I got rid of the Dexcool at 37k (it had been flushed a couple times up to that point). I just think the later pumps had issues (the replacement that failed was new GM). I have had several non-LT1s with original, belt driven waterpumps with well over 100k, so IMHO GM should pay as much attention to component quality as they do engineering. Like most other OEM parts on these cars, they are crap!

 

Should buy evanscooling stuff anyway, or distilled water with a bottle of water wetter.

 

Evans EPG coolant is not a direct replacement; need to change the pressure system to run.

 

Its just a different pressure cap... thats all