Oil on Plug and Coil (1 Viewer)

[UncleBanjo]

I was getting a misfire on cylinder 4, so I ordered coils and plugs figuring that was the issue.

When I tore it apart, this is what I found. What could be causing my plugs and coils to look like this? From a quick Google search, I found o-ring failure? Looking for guidance, as I don't want to put news plugs and coils in if this is the culprit for the failure.

Also, the coil boot was brown and looked to have overheated. Which if I recall, is a sign of oil getting to the coil/boot? Trying to get this up and running, as it's my only vehicle. Thanks for any help!

 

[jsloden]

Valve cover gaskets. You could try tightening the bolts and see if that helps. Not too much though. Use some compressed air and blow out the holes.

 

[UncleBanjo]

Sweet! How sensitive are these coil packs? If I run a new coil with bad valve cover gaskets, would it be damaged (or shortened lifespan) by the time I get the valve cover and spark plug tube gaskets delivered in the mail? Thanks for the help.

 

[Mike NXP]

Valve cover gaskets. You could try tightening the bolts and see if that helps. Not too much though. Use some compressed air and blow out the holes.

Valve cover gaskets won't have any affect on this but the spark plug / tube gasket within the valve cover could.
>>Failing tube gasket usually will show oil pooled up before taking the plug out. The top part of the coil seems dry it does appear that oil is coming from down below some how.

 

[jsloden]

Valve cover gaskets won't have any affect on this but the spark plug / tube gasket within the valve cover could.
>>Failing tube gasket usually will show oil pooled up before taking the plug out. The top part of the coil seems dry it does appear that oil is coming from down below some how.

Sorry, this is what I meant. I normally just consider the tube gaskets to be part of the valve cover gasket.

 

[Mike NXP]

Sorry, this is what I meant. I normally just consider the tube gaskets to be part of the valve cover gasket.

True that...but wouldn't the coil tube be all oily if it was leaking from above? Idk.....

Maybe try to clean up coil tube , replace with new plug , and just observe for a day or two. See if oil is pooling in tube before removing plug or if blowby is happening from down below. Idk just thinking out loud.

At least the plug came out and it didn't destroy any threads

 

[awesomeissquid]

True that...but wouldn't the coil tube be all oily if it was leaking from above? Idk.....

Maybe try to clean up coil tube , replace with new plug , and just observe for a day or two. See if oil is pooling in tube before removing plug or if blowby is happening from down below. Idk just thinking out loud.

At least the plug came out and it didn't destroy any threads

If it does end up appearing to be coming from the combustion chamber, try pulling the hoses off the idle-up control valve that is mounted on the power steering pump. It is possible for that to fail and to cause power steering fluid to back up into the engine. But if that is occurring you would notice the power steering reservoir being low.

 

[J1000]

To me that is a classic symptom of the spark plugs backing out and leaking combustion gases, oil leak is secondary.

Common issue.

 

[UncleBanjo]

Would a malfunctioning idle-up control valve cause a small leak in the power steering pump? The pump shows signs of a leak/weep. And how would I diagnose a bad idle-up control valve? Drive around without the hoses attached?

I guess what I will do for now is put a new coil and plug in the cleanest spark plug tube and take the old coil and plug (from the cleanest cylinder) and put it in #4 (the oily and misfiring cylinder). Then drive around and check it later this weekend for any oil and see what we find.

Be sweet if it is just from some loose plugs.

 

[Mike NXP]

Would a malfunctioning idle-up control valve cause a small leak in the power steering pump? The pump shows signs of a leak/weep. And how would I diagnose a bad idle-up control valve? Drive around without the hoses attached?

I guess what I will do for now is put a new coil and plug in the cleanest spark plug tube and take the old coil and plug (from the cleanest cylinder) and put it in #4 (the oily and misfiring cylinder). Then drive around and check it later this weekend for any oil and see what we find.

Be sweet if it is just from some loose plugs.

View attachment 3343282

The backside of the pump has the hoses that were mentioned. They are connected to a brittle piece of plastic so be careful , mine broke very easily. Its an easy fix either way.

You would also probably notice smoke out of the exhaust but either way good idea from squid to check it out .


Clean em up like you said and replace with new plug and report back in a few days. Maybe that plug just backed out a bit as suggested above . When my tube seal failed I had an inch or so of oil in the tube so it doesn't seem like you have that happening

 

[Bisho]

That is 100% oil getting into the tube from the tube seal in the top of the valve cover. They are most likely hard and brittle as charcoal. It probably doesn’t actually hurt anything, but it is messy.

The brown boots are probably original. I think they started life that color.

 

[UncleBanjo]

Thanks for all the help, everyone. This forum is awesome. Just wish I knew more so I could help others when they have issues.

But just got in from finishing up. I ended up replacing two coils (boots were brittle and cracked) and 4 plugs. All the plugs were pretty rough. The other two coils were decent enough to get a seal on the plug and will run those until I can get valve cover gaskets and plug tube seals.

I will wait on the power steering pump until I can take a peek this weekend and see if new plugs and good coils fixed it.

I'll put an order in for tube seals and valve cover gaskets tonight and hope they don't take too long to arrive.

For now it's running smooth and no CEL. I'll keep the thread updated and report back findings. Again, thanks everyone.

 

[Mike NXP]

Thanks for all the help, everyone. This forum is awesome. Just wish I knew more so I could help others when they have issues.

But just got in from finishing up. I ended up replacing two coils (boots were brittle and cracked) and 4 plugs. All the plugs were pretty rough. The other two coils were decent enough to get a seal on the plug and will run those until I can get valve cover gaskets and plug tube seals.

I will wait on the power steering pump until I can take a peek this weekend and see if new plugs and good coils fixed it.

I'll put an order in for tube seals and valve cover gaskets tonight and hope they don't take too long to arrive.

For now it's running smooth and no CEL. I'll keep the thread updated and report back findings. Again, thanks everyone.

Nice, glad the plugs came out without any issue. Do your research on the valve cover gasket job and using the proper gasket silicone in the right areas. soak those cover bolts and go easy to avoid anything breaking

 

[UncleBanjo]

Nice, glad the plugs came out without any issue. Do your research on the valve cover gasket job and using the proper gasket silicone in the right areas. soak those cover bolts and go easy to avoid anything breaking

Copy that, Mike NXP. I'll research tutorials and probably spray the bolts a day or so before the install to let them soak.

 

[abuck99]

Would a malfunctioning idle-up control valve cause a small leak in the power steering pump? The pump shows signs of a leak/weep. And how would I diagnose a bad idle-up control valve? Drive around without the hoses attached?

I guess what I will do for now is put a new coil and plug in the cleanest spark plug tube and take the old coil and plug (from the cleanest cylinder) and put it in #4 (the oily and misfiring cylinder). Then drive around and check it later this weekend for any oil and see what we find.

Be sweet if it is just from some loose plugs.

View attachment 3343282

FSM describes a procedure to test function of idle up valve—

 

[Bisho]

FSM describes a procedure to test function of idle up valve—

View attachment 3343883

Good luck pinching that hose if its original!

 

[leveeguy]

Just a thought, maybe check/replace PCV valve when the VCG and tube seal work is done

 

[UncleBanjo]

FSM describes a procedure to test function of idle up valve—

View attachment 3343883

Thanks for the FSM post. I'll give this a try when I open it back up this weekend. I'll let you know the results.

Just a thought, maybe check/replace PCV valve when the VCG and tube seal work is done

Good idea, leveeguy. I'll order the PCV valve and get that knocked out while I'm doing the VCG. Thanks for the heads up.

 

[J1000]

The brown boots are probably original. I think they started life that color.

Naw they are definitely grey.

 

[baltistyle]

To me that is a classic symptom of the spark plugs backing out and leaking combustion gases, oil leak is secondary.

Common issue.

Yup, either this or leak from above. Clean it up, monitor and check it after a few drives. Buying a box of coils online is not that expensive, imo.

If it continues, check into the valve cover gasket and spark plug tube seals within the valve cover, and use stock Toyota gaskets for these replacements. You will also need the valve cover bolts, etc for the proper torquing.