The engine runs well and the transmission shifts well. The only indication was the oil gauge dropping at a stop light. I immediately put 3 quarts in. There was nothing visible at this time. When I stopped 40 miles later, there was smoke from the oil and coolant mixture getting on the exhaust. At this point, it was pouring past the reservoir cap, and it was everywhere. The 3 quarts were gone in 40 miles. It still ran well. I put more oil in to drive onto the trailer I borrowed to get it home. Many people say head gasket, but I know of no pressurized oil that would be adjacent to the water jacket/head gasket. I assume the oil still travels through the lifter/pushrod/rocker arm path.

Does the lifter gallery crack in the block?

Why does the engine run so well?

Does the LT1 have oil paths different from the rest of the small blocks?

  • oil has to grease ur cylinders. located close to the head gasket. worst repair job ever conceivable your first time. u could need full time help. some guys can do it in a couple hours Apr 10, 2015 at 20:57

1 Answer 1


Your problem is probably with the oil cooler. The LT1 can have an oil cooler which pushes coolant through a housing at the oil filter. It cools the oil as it enters and exits the oil filter. Here is a diagram of the system:

enter image description here

You'd be looking at #4 where the heat exchange occurs. If this housing were to crack or have an issue, you'd be pumping oil into the coolant system due to oil pressure usually being much higher (should be over 2x the pressure in the system) than what the coolant sits at fully warm.

With this being the issue, it's also the reason your vehicle continues to run well.

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