Oil on spark plug
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Oil on spark plug 09 sierra 1500 5.3
at a stop sign the check engine light started flashing, tail pipes were smoking like a freight train, and the idle got real heavy. got into the shop I plugged it to a scan tool read off 02 censor offline , misfire cylinder 4 and cats were clogged .
cats seemed fine . 02 sensor replaced . Pulled the #4 coil and idle stayed ruff with smoke still barreling out the tail pipes . Pulled the spark plug for #4 and it’s covered in oil. Spark plug, threads, and hole were covered pretty good in oil. Seems like a bad seal on cylinder 4? Or a dropped cylinder ? Truck burned through about 2 quarts of oil in 15 mins of diag give or take a few mins . What are the thoughts here ?
at a stop sign the check engine light started flashing, tail pipes were smoking like a freight train, and the idle got real heavy. got into the shop I plugged it to a scan tool read off 02 censor offline , misfire cylinder 4 and cats were clogged .
cats seemed fine . 02 sensor replaced . Pulled the #4 coil and idle stayed ruff with smoke still barreling out the tail pipes . Pulled the spark plug for #4 and it’s covered in oil. Spark plug, threads, and hole were covered pretty good in oil. Seems like a bad seal on cylinder 4? Or a dropped cylinder ? Truck burned through about 2 quarts of oil in 15 mins of diag give or take a few mins . What are the thoughts here ?
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From: Schiller Park, ILL Member: #317
There is no code for a clogged cat. If you're referring to a P0420/P0430, those don't directly indicate a clog (no code does).
With that much oil burning and cylinder #4 obviously not firing properly, I think the engine will need to be broken down. You should start with a leakdown test to see where the compression is being lost, but I doubt it's a cylinder head issue if THAT much oil is burning.
With that much oil burning and cylinder #4 obviously not firing properly, I think the engine will need to be broken down. You should start with a leakdown test to see where the compression is being lost, but I doubt it's a cylinder head issue if THAT much oil is burning.
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Yes I am , commonly seen it’s need clogged or just bad and red hot cats in general apologies for the confusion there.
I’ll look at doing a leak down test i appreciate it . With you saying you don’t think it’s a cylinder head where are you thinkin the issue lays ?
I’ll look at doing a leak down test i appreciate it . With you saying you don’t think it’s a cylinder head where are you thinkin the issue lays ?
Just do the leak down test. From there you'll get your answers and BTW. A worn out valve stem seal on the intake valve will allow oil to be sucked into the combustion chamber and will oil the crap out of that cylinder which can lead to a clogged catalyst and oh yeah the choo choo train coming from the exhaust pipe. If it turns out to be worn rings then yes it's time for an overhaul.
With all that oil in No.4 cylinder you'll probably find a little higher reading on the compression but it's the percentage of leakdown that's going to be telling. When you are doing this test you will be able to determine the source of your leak and it's either going to be leaking mostly from the engine crankcase which can be heard from the oil fill cap indicating a ring issue, the exhaust pipe indicating a worn exhaust valve stem seal or the intake manifold indicating a worn intake valve stem seal. I will say that 2 qts of oil in such a short period of time is more than what a leaking valve stem seal will do unless there's more than one doing it. Have you inspected the other plugs to verify it was just No. 4?
Good luck and hope for the best outcome!
Good luck and hope for the best outcome!
Joined: Nov 2001
Posts: 34,632
Likes: 2,557
From: Schiller Park, ILL Member: #317
Just do the leak down test. From there you'll get your answers and BTW. A worn out valve stem seal on the intake valve will allow oil to be sucked into the combustion chamber and will oil the crap out of that cylinder which can lead to a clogged catalyst and oh yeah the choo choo train coming from the exhaust pipe. If it turns out to be worn rings then yes it's time for an overhaul.
I think it's more serious than valve seals, especially if the issue is just the one cylinder burning THAT much oil, but I completely agree with doing a leakdown test before anything else.
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Turned out to be a lifter that **** the bed and blew into 3 pieces . Rocker seized, rod bent and cylinder 4 froze in place . Got those replaced new gaskets and seals all the way around on left side of the block . Resurfaced the head it’s has some good groves in it, new cam . New spark plugs and and coil packs . No issues so far trucks running like a dream again
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Turned out to be a lifter that **** the bed and blew into 3 pieces . Rocker seized, rod bent and cylinder 4 froze in place . Got those replaced new gaskets and seals all the way around on left side of the block . Resurfaced the head it’s has some good groves in it, new cam . New spark plugs and and coil packs . No issues so far trucks running like a dream again
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Turned out to be a lifter that **** the bed and blew into 3 pieces . Rocker seized, rod bent and cylinder 4 froze in place . Got those replaced new gaskets and seals all the way around on left side of the block . Resurfaced the head it’s has some good groves in it, new cam . New spark plugs and and coil packs . No issues so far trucks running like a dream again
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. You replaced ONE rocker, and ONE lifter, and NEW cam?
Please post pictures of broken parts....
