Oil on the spark plugs

lmmr74 · 09-18-2012, 09:24 AM

Hello,

I was changing the spark plugs on my 89 Turbo and i realized that they had oil on the base (the are of the spark plug that ignits the fuel inside the combustion chamber), the first thing i thought was piston o-rings, but i did a compression test and everything was fine.
What can be the cause of this oil on the combustion chamber??

Thanks for the help!

LR

Sonyps307 · 09-18-2012, 03:57 PM

The valve cover seal get old and start leaking down to the spark plug. Then when u remove the plugs the threads and bottom get coved in oil. Check that black cover in the middle to that leaks to from the big 14mm Allen bolts.

Bru · 09-19-2012, 01:48 AM

I made a cheap tool to tighten down the 14mm allen center galley plugs. I used a 14mm bolt head
in the allen hole and 2 jam nuts tighted together on the threads. you just need to get a socket over the top jam nut to tighten. use decent quality material or else it could break / strip the threads. To sop up the oil with the spark plugs in I used a bent nose pair of tweasers to hold a patch of paper towel.

cre · 09-19-2012, 02:10 AM

See the thread in the FAQ section for detailed information on the topic, including pictures.

09-18-2012, 09:24 AM	#1
lmmr74 Stock Join Date: Aug 2011 Location: Portugal Posts: 21	Oil on the spark plugs Hello, I was changing the spark plugs on my 89 Turbo and i realized that they had oil on the base (the are of the spark plug that ignits the fuel inside the combustion chamber), the first thing i thought was piston o-rings, but i did a compression test and everything was fine. What can be the cause of this oil on the combustion chamber?? Thanks for the help! LR

09-19-2012, 01:48 AM	#3
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	I made a cheap tool to tighten down the 14mm allen center galley plugs. I used a 14mm bolt head in the allen hole and 2 jam nuts tighted together on the threads. you just need to get a socket over the top jam nut to tighten. use decent quality material or else it could break / strip the threads. To sop up the oil with the spark plugs in I used a bent nose pair of tweasers to hold a patch of paper towel. Last edited by Bru; 09-19-2012 at 01:53 AM.

09-19-2012, 02:10 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	See the thread in the FAQ section for detailed information on the topic, including pictures. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

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09-18-2012, 03:57 PM	#2
Sonyps307 Lexus & 550's Join Date: May 2010 Location: Baltimore Posts: 526	The valve cover seal get old and start leaking down to the spark plug. Then when u remove the plugs the threads and bottom get coved in oil. Check that black cover in the middle to that leaks to from the big 14mm Allen bolts.