Oil on spark plug threads why?
Thread Starter
Intermediate
Joined: Jan 2001
Posts: 47
Likes: 0
From: Stockholm Sweden
Oil on spark plug threads why?
How can oil get into the threads of the spark plugs ?
I can think of that the engine burns some oil and then compress the air
and maybe then if the spark plug isn't tigheten enough a small
amount would pass up thru the treads.
Is my assumption correct ?
I can think of that the engine burns some oil and then compress the air
and maybe then if the spark plug isn't tigheten enough a small
amount would pass up thru the treads.
Is my assumption correct ?
Burning Brakes
Joined: Feb 2001
Posts: 929
Likes: 5
From: Marietta GA
Re: Oil on spark plug threads why? (shark)
Remember there is some amount of spark plug threads that are exposed in the combustion chamber. As you remove the plug, the oil will then be spread to the spark plug holes in the head. Is the oil leaking past the plugs to the outside of the head with the plug installed?
If your spark plugs are oil fouled then obviously it is being sucked from the engine somehow. Some possibilities are bad piston rings, leaking intake manifold, bad valve guides, bad valve stem seals.
You must locate the source of the oil leak and then fix it. If it isn't using a lot of oil then you may consider a hotter spark plug (one heat range up) which may burn more of the oil than your current plug.
If your spark plugs are oil fouled then obviously it is being sucked from the engine somehow. Some possibilities are bad piston rings, leaking intake manifold, bad valve guides, bad valve stem seals.
You must locate the source of the oil leak and then fix it. If it isn't using a lot of oil then you may consider a hotter spark plug (one heat range up) which may burn more of the oil than your current plug.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Oil on spark plug threads why? (Jvette73)
With bad stem seals the oil will get burned as the car is driven. When you park the car,the remaining oil that has leaked into the guide will drip down into the cylinder and gather around the plug threads. It will eventually seep to the outside. Sometimes, after the car has been parked, you get a puff of blue smoke from the exaust on start up. That also would be the raw oil that had leaked down since the car was last parked.
Melting Slicks
Joined: Mar 2001
Posts: 3,365
Likes: 5
From: Lake Villa IL
Cruise-In IV Veteran
Cruise-In V Veteran
St. Jude Contributor
Re: Oil on spark plug threads why? (shark)
Thanks for asking a question that's been driving me crazy. I've been wondering the same thing. :yesnod:
Racer
Joined: Mar 2001
Posts: 372
Likes: 1
From: Ellicott City MD
Re: Oil on spark plug threads why? (shark)
Jvette73 and I had the same discussion this weekend. The only symptom of me losing 1 qt every 250 miles is a puff of smoke on startup and OILY SPARK PLUG THREADS. I looked all over Carlisle but couldn't find valve stem seals. Oh well, I'll check around locally now.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Oil on spark plug threads why? (fireball)
Fireball, checkjthrough Summit or Jegs for valvestem seals. Also, I know theres a speedshop out there near Colombia. Maybe somthin in Jessup. Or Coleman Bros. in Laurel.
[Modified by Jvette73, 9:59 PM 8/26/2001]
[Modified by Jvette73, 9:59 PM 8/26/2001]
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: Oil on spark plug threads why? (Jvette73)
Can purchase Felpro brand positive valve stem seals from Auto Zone, these are very good seals also, much better than the rubber umbrella type seals. They come with the little sleeve type tool to install them over the valve stem.
Just to provide a little "Bubba" storey, I just stopped much of the oil consumtion on my '88, 154,000 mile Dodge Carvan V6 engine, by adding 12oz. of Gold Eagle brand transmission stop leak to the engine oil. Oil consumption was due to old,hard, and dry valve stem seals(they were replaced once @80,000 miles), and I thought I'd try the transmission stop leak, since it is supposed to 'soften' old hard, dry seals. So far, seems to be working well, but I'd never do this fix on my '81, but for the wife's old van, I thought what the heck!!!
Just to provide a little "Bubba" storey, I just stopped much of the oil consumtion on my '88, 154,000 mile Dodge Carvan V6 engine, by adding 12oz. of Gold Eagle brand transmission stop leak to the engine oil. Oil consumption was due to old,hard, and dry valve stem seals(they were replaced once @80,000 miles), and I thought I'd try the transmission stop leak, since it is supposed to 'soften' old hard, dry seals. So far, seems to be working well, but I'd never do this fix on my '81, but for the wife's old van, I thought what the heck!!!
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