Join Date: Jan 2018
Location: Speeding in SoCal
+1 on oil analysis.
I recently had a similar "fuel in oil" discovery on one of my vintage cars when I sent it in for analysis.
I had the car on a racetrack, and it was running strong, with absolutely no indication of a problem, except for a suddenly-dropped oil pressure. It went from 70 psi to no more than 20 psi.
There was no overheating of oil or coolant, no smoke out of exhaust, no detonation, no stumbling, no oil smell or fuel smell.
Once back in the paddock, I opened the hood and the engine was cool enough to put my hand on the valve covers. Definitely hadn't overheated. The oil on the dipstick was clear and smelled clean. The oil level was near full. There was no fluid leaking or dripping anywhere. Radiator was full.
Had to be an oil pump, we figured. Or an oil pressure gauge/sending unit.
I put the car on my trailer and took it home.
Back at the shop, the oil gauge/sender checked out good. I decided on an oil analysis before doing anything else.
The analysis revealed fuel in the oil. As well as lead (from the 110 octane leaded race gas I was running at the track.) And some iron.
I had busted a piston ring, and blown part of the intake manifold gasket. But, the baffling part is how normally and smoothly the engine had continued to run. I've damaged/blown-up other engines in my day, and I know what that feels like. This didn't feel like that.
Lesson learned, and noted. If we'd merely replaced the oil pump, as everyone thought the culprit was, and not done an oil analysis, we wouldn't have suspected the ring. Like I said, there was zero smoke or any other of the usual suspects.
2018 Trackhawk black/black
2017 Ferrari 488GTB
1968 Shelby GT500KR
2014 Grand Cherokee SRT
2006 Corvette ZO6
2005 Dodge Ram SRT-10 Quad Cab
1977 Jeep CJ with 401
1970 Dodge Challenger R/T 440
1970 Dodge Charger R/T 440
1966 Corvette 427