Have high mileage Mustang 302 and it suddenly started blowing a couple of seconds of blue/gray smoke after interstate driving for at least 15 minutes. When I exit interstate, decelerate and then merge onto regular road and accelerate in 2-3 gear, it will blow a couple of seconds of blue/gray smoke and then clears up. I can drive in city, idle fine, runs like a top. I just did a complete tune-up and resealed engine and there are no vacuum leaks and the car runs beautiful except for the occasional smoke after high speed driving. I did take out spark plugs and only 1 plug was a greasy/oily mess. I think the oil is getting sucked up through the upper manifold via the pcv valve and then sent to the combustion chamber during high vacuum driving(interstate). Would a bad valve seal on that one cylinder that has an oily spark plug have a bad valve seal. I don’t think it’s a bad piston ring on that one cylinder, but I could be wrong. What do you think?
I’m doing a compression test this weekend and that could tell a lot. Do you think replacing the valve stem seal on that cylinder that has the nasty spark plug will/could fix the problem?
I’m having every symptom here. I got two questions tho, my truck struggles to start and usually only starts after about 3 cranks, is this another symptom of bad valve seals? And then my vehicle also sucks in air every now and then through the exhaust, is this another symptom?
Love it straight to the point and simplified
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Great information brother, thank you
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Have high mileage Mustang 302 and it suddenly started blowing a couple of seconds of blue/gray smoke after interstate driving for at least 15 minutes. When I exit interstate, decelerate and then merge onto regular road and accelerate in 2-3 gear, it will blow a couple of seconds of blue/gray smoke and then clears up. I can drive in city, idle fine, runs like a top. I just did a complete tune-up and resealed engine and there are no vacuum leaks and the car runs beautiful except for the occasional smoke after high speed driving. I did take out spark plugs and only 1 plug was a greasy/oily mess. I think the oil is getting sucked up through the upper manifold via the pcv valve and then sent to the combustion chamber during high vacuum driving(interstate). Would a bad valve seal on that one cylinder that has an oily spark plug have a bad valve seal. I don’t think it’s a bad piston ring on that one cylinder, but I could be wrong.
What do you think?
J - I think your diagnosis is spot on. There has to be oil coming from somewhere that is going into the combustion chamber.
I’m doing a compression test this weekend and that could tell a lot.
Do you think replacing the valve stem seal on that cylinder that has the nasty spark plug will/could fix the problem?
J - Wait and see after the test, but it certainly could!
sounds just like what i have going on.. Especially letting off the gas on a down hill , the next light it blows a cloud..
Cold start for about 5 seconds then it's gone
I’m having every symptom here. I got two questions tho, my truck struggles to start and usually only starts after about 3 cranks, is this another symptom of bad valve seals? And then my vehicle also sucks in air every now and then through the exhaust, is this another symptom?
P - Are you getting any engine codes? We have a video that could help your research: ruclips.net/video/0YRdzJbHcm4/видео.html
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S - Thanks!