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 Post subject: oil cap blowby
PostPosted: Fri Mar 28, 2014 11:25 pm 
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Pacer
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Location: pueblo colorado
for the last few months I have been having a problem with Eagle Eyes pushing oil out through the oil cap and the valve cover grommets and for the life of me I can't figure out why she is doing this, so I figured I would ask you guys to see if you had any idea why she is doing this.

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 Post subject: Re: oil cap blowby
PostPosted: Sat Mar 29, 2014 7:16 am 
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Javelin

Joined: Mon Oct 14, 2013 7:35 am
Posts: 224
Location: Bloomsburg, PA
Blow by is caused by worn rings, pistons, and cylinder walls as far as I'm aware. There really isn't much you can do without doing major engine work as far as I'm aware. Maybe someone else knows more, but that's always been my understanding of it. If while the engine is running, with the oil cap off, you can see or feel puffs of air coming out, that's a fairly good indication of worn parts. The explosive gases are able to escape around the pistons and rings and that's where they come out. Excess blow by will also cause gas to build up in your oil, you should be able to smell it if it's bad enough.


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 Post subject: Re: oil cap blowby
PostPosted: Sat Mar 29, 2014 10:49 am 
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Hornet
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any engine will always have a little blow by. that's where the pcv system comes into service. pcv keeps the crank case under vacuum under normal operation.

check your pcv valve, make sure its not stuck closed. take it off and clean it with some brake/carb cleaner. if the pcv is working, and still have blowby, you may have worn out cylinders/rings. with the car idling, take a piece of paper, and lay over the oil fill cap. if its worn out, the paper will bounce up and down. usually its just one cylinder that's worse than the others, so when the pcv cant keep up, that pressure has to go some where.

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 Post subject: Re: oil cap blowby
PostPosted: Sat Mar 29, 2014 12:46 pm 
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Javelin

Joined: Sat Apr 06, 2013 10:51 am
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Location: Oshkosh, Wis.
They are all correct. A 258 can run for a very long time that way it will just have allot of blow by...like an old diesel engine. May use oil and loose a bit of power. A good way to check the condition of the piston rings is a compression test.

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