My car recently had trouble starting. I took it to the mechanic for some other problems and he found it had only a quart of oil in it, even though the last oil change was 3,000 miles ago. He said nothing was wrong with the engine, but there was a lot of sludge under the valve cover. He cleaned it and topped up the oil.
A week later, the car really had trouble starting, so I pumped the gas and it started up, but I smelled burning outside the car. I checked the fluids, and it was shy on antifreeze but the oil was still full and fresh.
The check engine light came on, and the codes were misfires in cylinders 2 and 4. I changed the spark plug wires, which needed done anyway, and the PCV value, which was definitely sludgy. In the process, I checked my spark plugs and found traces of oil not on the electrode, but on the base ring around the electrode. After running the car for a bit, I re-pulled the plugs and found no oil.
The car starts OK now, but I’m still worried something is wrong and I’m wondering whether I should be driving it or shopping for a new car before it completely quits.
a 2000 what? knowing the type of car is helpful in these cases. otherwise, I can only take a WAG that with the oil consumption you describe, combined with the “sludge” on the inside of the valve cover makes me think you have excessive blow-by, which could be excessive cylinder wear (taper) or badly worn or broken rings.
What exactly are “traces?” Which electrode? What do you mean by “base ring” around the electrode? Please refer to this diagram to describe where you mean.
Find a user group for your kind of car/engine. If you do, you’ll find that this problem has been discussed numerous times, as has the problem with the seatbelts, the a/c, the etc etc. in short, user groups get around to discussing everything, sooner or later.
Offhand, I’d not be quick to discard this auto. I think a mechanic needs to assure that all the pressure equalizing devices are free and clear and that you get a good flush of the oil system. I used to use a few tablespoons of ATF in the oil to increase the cleaning capability of the fluid whenever I had a sticky lifter or excess oil usage due to possible stuck piston rings. use too much and you’ll ruin some of the seals and gaskets and start really using oil, but a little bit generally helps.
By traces I mean I could smell it and wipe a small bit off with my finger, but it wasn’t very much oil. It wasn’t on either electrode, but rather on the north end of the threads, on the same piece of metal as the ground electrode, the part that surrounds the center electrode.
"I changed the spark plug wires, which needed done anyway, " And now the car runs okay. What was your question again?
100K is not the magic number anymore. Modern cars should easily run double that. You’re burning (or losing) a quart every 1,000 miles - that’s not so bad. Check your oil when you buy gus.
Make sure that you don’t have oil leaking from the valve cover or something else higher than the plugs. Oil may have puddled around the plugs and dripped on the base of the plugs when you removed them.
However if you were down to a quart of oil left, it’s possible that you ran the cylinders dry and now it’s going to burn a little oil. It’s also possible that you were 3 quarts or so low as the engine is already burning some oil and that’s what got the plugs wet.
You could do a compression test. If it shows low compression pressure, the engine might have suffered damage from the low oil. If the pressure is OK it’s still possible that the oil rings are worn or valve seals are going bad. In that case I’d just check the oil level at least weekly and drive it. You could try an additive with the word “Mystery” on the can to see if it can loosen up the oil rings.
If the oil burning gets bad enough, it could mess with the O2 sensor enough to not be able to pass an emissions test if your area has them. It’s also embarrassing to drive with a cloud of smoke following you.
It sounds like you probably solved the starting problem by replacing the plug wires.
If you had said there was a bit of gasoline on the plugs where you described, I’d figure that was from the plugs not firing due to the faulty plug wires. If it was indeed oil, and the plugs were not oilfouled, my best guess is what JerrySTL suggested, a bit of leaked oil in the spark plug recesses that got onto the threads during removal. There wouldn’t have been enough running time after that for more oil to pool up in that area, hence no oil seen the second time.
Nothing mentioned so far suggests a major problem. The misfire apparently is fixed. Oil consumption is of some concern, but probably not enough to warrant replacing the vehicle. First it should be inspected for oil leakage, which is the most likely explanation for it to have lost ~3 quarts in 3,000 miles. Most oil leaks are not terribly expensive to fix.
1,000 miles per quart of oil is the upper end of the rule of thumb for acceptable oil burning, so if there are no leaks there’s not a compelling reason to fix that. The repairs to address excessive oil burning are expensive, from several hundred to a few thousand depending on the cause. I wouldn’t worry about it unless it loses that much oil with NO external leakage, in which case the worry would be that it might get worse over time and become a big problem.
It would be wise to check the oil more often so as to keep the level in the okay zone.
As suggested. Your next step is a compression test. Low compression in that cylinder (or more cylinders) will give you an idea of what lays ahead. It could be a problem with the valve, or with the rings, or both. It’s time to have the car looked at by someone with the proper tools to diagnose the problem. With 123k miles, the engine could use some TLC if you plan on keeping the car.
A compression test is appropriate if the engine doesn’t run smoothly or doesn’t produce full power, and ignition and fuel delivery problems have been eliminated. That doesn’t seem to be the case here, though.
in my experience, a compression test won’t reliably tell you anything about excess oil consumption (that is, assuming it’s not an external leak.) The F-250 I had would gulp a quart of oil a week, a compression test showed every cylinder in-spec (410 psi +/- something) but the leakdown test indicated excessive blowby which is known on those high-mileage Navistar diesels. An engine can run “fine” with a ton of blow-by but you’ll see things like gunky oil and in severe cases watery oil slop getting into the intake through the PCV system.
