Cylinder 3 was misfiring. I changed out the spark plug, and the old one had mineral deposits and oil on the threads, but no oil on the ceramic part. I don't think it's abnormal for the spark plugs to be oily, and it had been a long time since the spark plugs were last changed out. It stopped misfiring after I changed out the spark plug, but I want to know if it's a sign of future problems. I haven't done a compression test or a leakdown test. Ideally, I could just stop with changing out one spark plug and do nothing else, but I also realize it could be anything from the valve cover gasket, to valve seals, to something bigger that'd require taking off the cylinder heads and lapping the valves, replacing the cylinder head gaskets, etc. I don't want to have to go through that again if I don't have to, since my last attempt at rebuilding an engine from a different car wasn't successful, and I was without a car for months.
'04 3.8L V6 mineral deposits and oil on #3 cylinder. Does it need a rebuild or something simpler?
- Thread starter joeybuddy96
- Start date
gkomo
now i can hopefully expect to receive the shaft
I'm going through something similar on my 5.0 on cylinder #7, however mine seems much more aggressive. I have oil on my plug threads and my plug gets fouled (but no deposits like yours) every two weeks or so. I will tell you the same thing everyone has told me to do from my thread, compression and leak down test (which i have yet to do myself).
In the meantime, i'm trying the 'cheaper route' of adding oil and fuel additives to help my situation.
How long does your plug last before getting caked with deposits and oil again?
In the meantime, i'm trying the 'cheaper route' of adding oil and fuel additives to help my situation.
How long does your plug last before getting caked with deposits and oil again?
This is the first time I've changed out the spark plug since I got it. The last time they'd been changed was over two years before that after sitting idle for two years, so I'm hoping it's all just from age and nothing to worry about.
Doesn't look good. First thing in my mind is coolant. Did some Google-ing to confirm as best I can. Hate to be the bearer of bad news, but....
View: https://youtu.be/QEn3x0y5G2o?si=2vYf55VHekzirlag
View: https://youtu.be/QEn3x0y5G2o?si=2vYf55VHekzirlag
It sounds like according to that video, that could mean either the intake manifold gasket (I think there are three of them) or a leaking head gasket. The engine oil that leaks onto the pavement (that's another thing that will be hard to track down, although the transmission pan does have oil on it--I'll have to clean it to see where that's coming from) or on the dipstick doesn't have that creamy Irish liqueur color or consistency. I'll try checking one of the other spark plugs to see if it has that same residue on it later, or maybe fish the old one out of the trash to examine the color of it again. If it's got to be one of the two, I'd prefer it to be the intake manifold gasket--if it's the cylinder heads, I dread having to take all the timing components off, yoinking the cylinder heads, and especially trying to put the puzzle back together, etc..
This video says it could possibly the valve seals, or in the worst case scenario, major engine problems.
View: https://www.youtube.com/watch?v=lVCs5gWLUyI&t=1m50s
I should also mention that oil does appear to be leaking from the head gaskets, I think, but I haven't seen it in the coolant or in the transmission fluid. It's losing 1-3oz of motor oil every time I drive it about 20 miles; that's about how much motor oil ends up on the garage floor after each trip. I don't know what the cutoff point is for an acceptable amount of leakage before it becomes severe enough to make replacing the gaskets unavoidable. The last time I tried to rebuild an engine, the costs got really out of hand (I took that car's cylinder head to get resurfaced, valve job, got connecting rod and crankshaft bearings, new timing belt, tensioner, etc), so I'm thinking about just what actually *needs* to get done. I haven't done the leakdown/compression tests yet.
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