Coolant in my oil. WHY??

[cojo428]

OK, I'm gonna try to make this as short as possible. I was at the track. (1990 GT, 306, Trickflow, S-trim, 12 psi) Very conservative. I normnally trap at 122-125MPH but I had my BTM backing my timing down so low I was trapping at 109MPH. I was conservative because I wanted to see how my ET's were going to act at the top end. 2nd run the car heats up and I get out of the lanes. After opening the radiator cap I realize it's because the coolant is very low. Where did it go? Right in my crankcase, which became obvious after pulling the dipstick. Normal head gasket failure right??

BUT...
No steam in the exhaust. No oil in the coolant. No signs of detonation on the plugs. Absolutely no coolant coming out of the pipes, and as I said there should be no reason for it because I was running so conservatively and had added 3 gal of 105 octane fuel for insurance. So I go home, pull the U & L intake and appear to find the problem. Looks like I might have I overtightened the lower intake, maybe mashed a gasket, and there is coolant leaking into the valley pan. It all seems to make sense! So I fix it, pressure test it, and....

STILL coolant draining into the oil pan at a rather rapid rate. It's not even much of a drip. I can hear it pouring in there. I cracked my old block. Could that be the reason? It there a coolant plug somewhere that could have popped? I estimate only about 360 RWHP or so at that point, even though I have dynoed that combo at 498 RWHP with the BTM where it should be. Any other ideas how coolant can get into the crankcase so easily without getting oil in the coolant? I would appreciate any ideas at before I start taking it back apart to yank the heads off.

As always, Thanks!!

 

[Michael Yount]

Is it possible you've got some sort of front cover/gasket failure? That can dump coolant in by the timing chain/front sump.

I have had one car that was losing coolant with blown head gasket symptoms. But it was actually running just fine - a bit of steam on start up, but then none, ran fine - but constantly losing coolant. Turned out I had a hairline crack in the combustion chamber (head) that would only leak when the engine was hot after the car was shut off. When the car was cold, or even hot but running it wouldn't leak. I suppose you could have a cracked component that's cracked in a location that's leaking into the crankcase. And since crankcase pressure is almost always lower than coolant system pressure, no oil would end up in the coolant. Just thinkin' outloud.....

 

[89rdgt]

what he said front cover. but if its that bad it looks to me like your going to have to start by removing your heads. Check the block surface, head surface, gasket, ect. You can also inspect the front cover at the same time. If you can get ahold of a block tester or have one. Test to see if there is any exhaust gas in the cooling system.