I just found out that my 94 Z28 is leaking coolant into the oil. When I test drove the car it ran like a top and had no signs of water leaking into the coolant, such as clean oil etc... But the day I took delivery of the car it had no coolant and severly overheated. I limped it home, let it cool, and we put at least 2 1/2- 3 gallons of coolant/water mix.

Now fast forward two weeks and my car stumbles in the low RPM's when its warmed up and my low coolant light comes on, I check it this evening, and its fricken low. So I put one gallon of mix in and drive to get more. I get home and check my oil, and I can tell that its got water in it.

So what does this excatly mean? I have heard that LT1's leak coolant into the oil occasionally. But could it be a blown head gasket, or a warped head from the heat?

Me and my buddies are going to tear the top half of the engine apart and try to pinpiont the problem. Can you give me any tips when taking it apart, its my first time doing something like this, and its my buddies first time doing it to an LT1.

Well I wont find out untill friday or so when we take it apart, but has any of you had an experience like mine on this? I would appreciate any and all responses.

Thanks a ton,
Andrew

 

It's either intake or head gaskets. That is if there are no cracks. Don't bother putting the cork end gaskets on the intake. Use the the black permatex. When you refill it, open the bleeders until coolant comes out and then close them. Fill it up to full. Run it for a little while with the cap off until the thermostat opens and the level goes down for the last time. Fill it up to full, cap it off and fill the over flow tank to the correct level. Only cut the coolant with distilled water NOT tap water.

Pull on the battery, more than likely the battery hold down is broke. Go ahead and get a new overflow resevoir if so. That way your ready to go Friday. May not be a bad idea to get new hoses, belt and tensioner either. Drain most of the coolant from the petcock on the radiator so as little as possible, comes out the top and down on to the opti. If I were doing it, I would replace the water pump also. I'de rather do all the water system now and not have to come back and do part of it again.

Look real close at the hoses for the heater core. The factory crimps for the ends like at the black plastic restrictor leak all the time. This would be a real good time to replace or fix them. I like to hacksaw the crimps off and replace the hose and use the normal worm type clamps.

It's also a real good time to flush the coolant system and especially the heater core. I found that the block gets build up inside over time and constantly sloughs off debris and clogs the heater core. Seems every winter, I have to flush the damn heater core. Best to do it all now since the heater core costs about 500.

Oh yeah, one more thing. Remove and check the intake snorkel to the throttle body. Chances are one end is ripped. This is a good time to replace it if is. The factory part is expensive and ugly so just get an aftermarket one like trick flow or others but be sure it has a place for the IAT sensor.

Dave

 

If you got the money, get the heads machined and all that good stuff.