Diagnosis Needed - Oldsmobile Fouling Out

[88Drvr]

I have a 1998 Oldmobile Eighty Eight. It has a 3800 Series II 3.8L V6 engine w/ 80,000 miles. It was running great and it just fouled out. We replaced the plugs because they were a mess and were covered with oil. At the same time, we replaced the battery because it was swollen and old and the starter was replaced too. After doing all of this, the engine ran great for about a minute then it fouled out again going out slowly like it was running out of gas. The new plugs are now evenly covered with oil. There were no noises before the engine stopped either time. No rattling or clacking. We suspect a cracked intake manifold, but would rather find someone who has run into this problem before pulling everything apart.

[PetChemMan]

The possibilities that come to mind are a cracked intake that is pulling oil up from the block, a defective intake manifold gasket that likewise allowing oil to be sucked in from the lifter valley, a blocked PCV system that is blowing oil into the intake, a crankcase that is overly full of oil , spark plugs that are way too cold, or an ignition system problem that is allowing the plugs to become gasoline fouled.

I had a car brought to me that was smoking and misfiring during hard acceleration. The problem was 9 quarts of oil in a 4 quart sump ! I can see having 8 quarts in the sump, which would occur if someone " changed" the oil without draining the sump first, but having 9 quarts means someone not only changed the oil without draining it, but then added another quart on top of that ! The dipstick was correct for the engine.

On another subject, one lesson I've learned ( repeatedly and the hard way) is never to go charging off investigating a problem just because the owner told me what he thought the problem was. Usually, the owner's diagnosis is incorrect, and can cause a lot of wasted time investigating. For instance , the owner of the above car with 9 quarts of oil brought the car to me because he thought it had a brake problem ! He thought the surging and bucking of the car was due to the brakes coming on. In another case, a chainsaw was brought to me with a reported ignition failure. It turned out he had put chain bar oil into the gas tank, and gas into the chain oil tank. When he came back to pick up the chainsaw, I told him what the problem was, and he asked me how I had started with investigating an ignition problem and worked my way to the final problem. I told him the first thing I did was check the gas tank, and I never investigated an ignition problem. There was a moment of silence, during which he realized that his diagnoisis was never taken seriously !
Certainly, what the owner reports is your starting point, but don't forget to check the basics and and make your own analysis first.

[88Drvr]

Thanks for your response. We looked up TSBs on the car and found one that mentioned a blown seal in the plastic upper intake where the EGR valve connects. We rechecked the plugs and realized that the liquid on them could very well be coolant and gas. We removed the upper intake and there was a blown seal. We replaced the upper intake which was available at the local parts store (now comes with a reinforced sleeve where the EGR valve connects), and the guy at the parts store said he had seen dozens of these. That reinforced our diagnosis. Once the upper intake and the fouled plugs were replaced the car ran like a top!

We were lucky that we checked the TSBs or we might have run off half-cocked and replaced things we didn't need to. This lends creedence to your comments to investigate from square one before jumping into fixing the obvious and wasting time and money.

[PetChemMan]

I'm glad you found the problem ! A problem like that, unique to only a couple of engine lines, can certainly take time to track down. Usually, antifreeze getting into the cylinders will show up as excessive white smoke coming out the tailpipe, whereas oil causes blue-black smoke and too much gasoline causes sooty black smoke ( with a bad smell if the car has a catalytic converter). Speaking of unhappy smoke and odors, there's also the dreaded white smoke with an overheated electrical smell, always an immediate worry, especially if it's coming from the dashboard ! I suppose we have to also mention the raw gasoline smell coming from under the hood, the burning rubber smell from something bad happening to a tire, and the overheated brake smell from a dragging brake pad. I once had an underhood fire from power steering fluid spraying from a broken hose onto an exhaust manifold, and as I recall it smelled like hot automatic transmission fluid, plus, of course, a lot of smoke.

[Oldsguy]

I had a coil rupture and spill the coolant/oil all over the back of the engine and the driver side exhaust. That is a nasty smell that takes forever to go away.

On the subject of mis-diagnosis, I repair two-way radios and we often get radios in for repair with notes like "has a short in it" or "won't turn on" and when we check the radio cannot find a problem but the owner forgot to send in the battery with the radio and that turned out to be the problem....etc. Seen some real good ones............