Any ideas how fuel gets into oil?


solid fixture here in the forum
Staff member
I think somewhere in the past there was a known failure with the very popular, mass produced 3800 v6 motors found in millions of Chevys, Pontiacs, Buicks and Oldsmobles from the late 1980’s to the early 2000’s.

My wife took the kid’s car that doesn’t get driven much at all to the pharmacy on Thursday after dinner. 6 miles awy she noticed smoke coming from under the hood. When she parked she pulled the hood open and noticed smoke coming from under the coil packs where the sparkplug wires connect at the front right side.

I got there 30 minutes later and started investigating. Nothing looked burned in anyway. I started the car. It started very quickly, no unusual noise, no smoking and idled smoothly. I was looking for any belt problem, idler pulley not seized, alt, AC, air pump and steering pump all good. I shut the car off and pulled the dipstick. Right off I noticed the oil was very thin. Ran (dripped) right off the stick and its smelled of gas.
We had it towed home. I will start working on it Monday at lunch time. I plan to drain the oil but catch what first comes out in a glass jar just to see if it will clearly separate.
The car has 90,000 original miles and its a 1995 Buick LaSabre Limited 3800 series engine. I could’t find anything that made sense on a Goole search - it could be I just didn’t dig deep enough, not sure.
Anybody have any ideas? my OBD reader doesn’t help, what can I use? Are there any codes for this year?
You have to use a jumper across two pins on the connector. Then turn the ignition to on (do not start engine) and count the number times the Check Engine Light flashes. IIRC, it will go thru all the codes and then it will repeat. So once you see the pattern of codes starting over you are done.

The link will explain exactly how it's done and what pins to jump across, plus all the codes. That is from 12 to 99, that's all the possibilities.

fuel tends to get in oil from leaking or stuck open injectors, ID start looking there first
you could pull the injectors and fuel rail, reassemble , reconnect and check function, and measure flow
or you do what most people do, you pull the injectors and send them in to be checked, for function and flow measured and cleansed or replaced if required.
yeah a noid tester and a multi meter can be used to check if the injector harness is functioning, and a fuel pressure gauge can verify your fuel rails are maintaining pressure but it take special equipment to verify injector function
obviously you can change oil and oil filter, and your fuel filter(s) and then, dump a couple different brands or cans of injector cleaner into the fuel tank and go driving up and down the local streets so your not far from home if you find the car needs to be tower, as that might help free up the injectors, if they are sluggish in function, or partly clogged.

lots of vendors provide the service

don't ignore related thread and sub linked info:facepalm::like:
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I’m going to run my injector cleaner and dump a load of cleaner in the tank full of gas she just filled minutes before.
Take the car out for a long drive and check the oil. Of course making sure the car is out in the open so if it catches on fire . . . . .