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View Full Version : Help ! Oil in spark plug slot


dlgeary
09-15-2006, 03:01 PM
I need some help from the experts!

I am a new owner of a 94 ZR1 (6 Months) and last night when I was changing spark plugs, the #5 cyl spark plug was covered with oil on the outside. I pulled the boot and oil dripped out of it and when I pulled the plug it was tight and looked the same at the other ones but with oil on the outside. All other plugs were fine.

The car has been running fine. I suspected the crank case vent that enters the plennem just above this plug, and checked the PCV valves but they were fine. There are no visible signs of oil.

Where do I start looking?
Don

Jeffvette
09-15-2006, 04:02 PM
Don, has the engine been apart at all?

How high up the boot was the oil?

dlgeary
09-15-2006, 04:56 PM
I do not know if the engine has been apart, it only has 24k miles but had several previous owners.

The oil was about half way up the boot.

I have not started it since changing the plug but no more oil leaked into the slot while I had it apart.

Jeffvette
09-15-2006, 05:41 PM
I'm thinking the oil is comming from the seal inbetween the cam cover and the cylinder head. This is not a place oil usually gravitates to if it is leaking from someplace else.

dlgeary
09-15-2006, 08:01 PM
That's what I am afraid of too. Do you think that the first thing I need to do is take the plennum off to see what is going on in there. That is no small task in itself.

Jeffvette
09-15-2006, 09:58 PM
It's fairly simple to remove the plenum.
http://www.pnwzr1.net/LT5_tear_down.htm



I would suggest running the motor with out that psark plug plugged into the head and see if you have any seepage from the seal.

Jim Jones
09-16-2006, 03:38 AM
Actually with the help of Jeff's site, I took the plenum off without too much trouble. I printed off everything related to the LT5 teardown from his site and put it in a three-ring binder. It was VERY helpful, as I am a complete novice mechanic (that was my first major undertaking, and the car still runs!)

Good Luck!

Jim

Hotrod
09-16-2006, 04:24 AM
FYI: There is an "O" ring seal between the the heads and the valve (cam) covers. When the seal goes bad, oil from the cams, works its way up around the spark plug (outside) and wets things down with oil.

dlgeary
09-16-2006, 11:50 AM
OK, Thanks guys.
Jeff, these instructions are great. I will print them off and do some investigating. Looks like the only way to change spark plug wires is to take the plenum off anyways.

I have a full shop manual but sometimes those aren't descriptive enough.

dlgeary
09-18-2006, 09:22 PM
OK, you guys are NOT going to believe this but...

I had this idea to put some high temp Peratex Ultra Black sealant on the small lip inside the spark plug slot where the cam cover meets the head. There was a small lip because the cam cover was a little larger than the rest of the spark plug hole. I let it dry and cure for 24 hours then drove the car to our club picnic about 20 miles from home.

I checked it when I got home and no oil. I am sure this is a temporary fix but at least it works until I have time to take the plenum and cam cover off to fix it right.

Thanks again for your help. Jeff that website is awesome.

Jeffvette
09-18-2006, 10:21 PM
You said cylinder #5 which should be the drivers side, but if it's the passenger side you do not have to remove everything on top to get the cam cover off. Just remove the passenger side coolant pipe coming from the injector housing.

Thanks for the compliment on the site. There are several projects I wish I had documented.

Rest of the tear down here.

http://www.pnwzr1.net/LT5_tear_down2.htm

dlgeary
09-19-2006, 02:12 PM
Yes, it's #5 and on the driver side. I was just wondering if I could get the cam cover off without taking off the plenum and everyting on top.

So you're saying that I can take the passenger side off but not the drivers side. without removing the plenum?

Thanks
Don

tccrab
09-19-2006, 03:22 PM
Yes, it's #5 and on the driver side. I was just wondering if I could get the cam cover off without taking off the plenum and everyting on top.

So you're saying that I can take the passenger side off but not the drivers side. without removing the plenum?

Thanks
Don

Well, not speaking with any authority since I've not had the pleasure of taking the drivers side cam cover off... but will someday to get it powdercoated...
You will for sure have to remove the brake booster, but I can't tell for sure if the plenum has to come off to snake the cam covers past the air conditioner lines.
If you can get the cam cover past the air conditioner lines, then looks like the plenum can stay on.
Jeff? Johnny?

TomC

Jeffvette
09-19-2006, 03:44 PM
Well, not speaking with any authority since I've not had the pleasure of taking the drivers side cam cover off... but will someday to get it powdercoated...
You will for sure have to remove the brake booster, but I can't tell for sure if the plenum has to come off to snake the cam covers past the air conditioner lines.
If you can get the cam cover past the air conditioner lines, then looks like the plenum can stay on.
Jeff? Johnny?

TomC

Pick your poison. Remove the plunum to get the AC compressor out of the way for the cam cover to be removed, or evactuate the AC and disconnect the lines.

Then you still have to remove the brake booster and coolant pipe and move the Power steering pump stuff forward.