Oil leak around spark plug

[kat]

So, between me and my buddy we have 40+ years of turning wrenches and nether one of us has seen this. As you can tell by the pictures, I have oil seeping slowly out from around my number 8 spark plug. Its a '94 5.8L that has roughly 30k on it.
I was noticing a small oil leak coming down the drivers side of engine. I replaced the valve cover gaskets with cork thinking that was the issue. Cleaned up around the #8 plug and put some miles on it only to find that it still had oil gathered around the plug. Thinking I had oil gathered around the plug from the valve cover gasket issue, I then changed all spark plugs which were showing clean (white), cleaned area around plug and put about 40 miles on it at the time of the pictures. The engine runs like a champ, no skipping, doesn't smoke, no milky oil, doesn't run hot, but still has a small leak coming from around the plug. As far as I can tell its the ONLY plug that has a leak coming around. Between me and my buddy we thought a hair line crack in head, but it sure don't run like it does. Anyone have any ideas?? The oil is hard to see but if you look close at the bottom of the plug you can see it.

 

[Speedrdr]

Unless there’s a ‘pixie’ hiding under your hood…just kidding. Not sure if a go-pro would survive in that environment, but it would be an interesting option.

Randy

 

[Timmy390]

I've used Leak Detector UV Dye to solve many a mystery oil leak

Tim

 

[ba123]

+15 on the dye.

Is your pcv set up properly?

 

[SevenT]

That valve cover is still leaking. Clean plugs tell you there is no blow-by and the reason there is no blue smoke out of the exhaust. Get some Fel-Pro metal impregnated rubber valve cover gaskets and do not over torque them.

 

[Broncobowsher]

Valve cover reseal... didn't seal.
Or at least you didn't get everything really clean after you sesealed. I go with it still leaks.

 

[cldonley]

x10 on the valve cover gasket. If there were a crack in the head, or oil getting by the rings or valve seals, you'd have other symptoms or you could pull that plug and see oil in the cylinder/fouled plug.

 

[kat]

I haven't pulled the new plug but the plug prior had oil on threads of spark plug but it all was white, no fouling. For the life of me I cant see any oil anywhere else. I have used every type of gasket and landed on the cork for the last one. Wire wheeled the old gasket off with bench grinder so the thing is clean. I even put new valve cover bolts on them. In the back of mind I'm thinking the aluminum valve cover them selves are at fault.
Where do I get this leak detector you're talking about?

 

[Timmy390]

Got my leak detecting dye at Advanced Auto as they were the closest parts store to me. You will also need a black light, I bought this one as it's easy to use in tight spots
https://www.lowes.com/pd/CRAFTSMAN-UV-LED-Miniature-Flashlight-Battery-Included/1001033788

https://www.autozone.com/test-scan-...VUCzUAR0bEAfnEAQYASABEgKLA_D_BwE&gclsrc=aw.ds

The dye works great in the radiator too......some examples Both were pains in the butt to find.....cracked oil pump o my Samurai and cracked head on the Bronco

Tim

 

[ared77]

Great information guys.

 

[kat]

Got my leak detecting dye at Advanced Auto as they were the closest parts store to me. You will also need a black light, I bought this one as it's easy to use in tight spots
https://www.lowes.com/pd/CRAFTSMAN-UV-LED-Miniature-Flashlight-Battery-Included/1001033788

https://www.autozone.com/test-scan-...VUCzUAR0bEAfnEAQYASABEgKLA_D_BwE&gclsrc=aw.ds

The dye works great in the radiator too......some examples Both were pains in the butt to find.....cracked oil pump o my Samurai and cracked head on the Bronco

Tim

Wow, I didn't even know something like this existed. So just one bottle will work for engine?? It didn't say on there web page.

 

[ba123]

A couple corrections… that one you mention @Timmy390 looks great, but note that the light needs to be UV (which you did link) and not black light (you mentioned). Although some black lights might work, just depends.

Also. For coolant, you must use one that is compatible with your coolant…be sure if you need to do that.

Lastly, most coolant will show from black light and you might not need any additive. I know we aren’t talking about coolant, but since it was brought up….

Dye can be a lifesaver for oil since it goes everywhere and hard to tell. You can usually see a path and it’s the best thing ever. No reason not to use it.

 

[Timmy390]

A couple corrections… that one you mention @Timmy390 looks great, but note that the light needs to be UV (which you did link) and not black light (you mentioned). Although some black lights might work, just depends.

Also. For coolant, you must use one that is compatible with your coolant…be sure if you need to do that.

Lastly, most coolant will show from black light and you might not need any additive. I know we aren’t talking about coolant, but since it was brought up….

Dye can be a lifesaver for oil since it goes everywhere and hard to tell. You can usually see a path and it’s the best thing ever. No reason not to use it.

You can use a black light too. I used a black light before buying the UV light I linked.
https://www.lowes.com/pd/CRAFTSMAN-...-prd-_-mdv-_-gdy-_-all-_-58551400-_-27795-_-0

One bottle of the dye will do.

Tim

 

[kat]

You can use a black light too. I used a black light before buying the UV light I linked.
https://www.lowes.com/pd/CRAFTSMAN-...-prd-_-mdv-_-gdy-_-all-_-58551400-_-27795-_-0

One bottle of the dye will do.

Tim

Had to order the dye and flashlight thru Amazon and should be arriving this week. Just a couple quick questions. After pouring it in thru oil fill, how long does it take to see it?? And how long does it last??
Reason is Im in need of oil change and was wantind to do this prior to changing oil because I don't like the idea of it being in there. And didn't know if there was a 'window' where it works best. I have a feeling the best time to see my leak would be at night or in a dark area.

 

[Timmy390]

I would clean up all the oil on the engine before putting the dye in

I poured it it and ran the engine to operating temp. Let it cool, turned the lights off in my shop and went full CSI on the engine. I did the same with it in the radiator.

Tim

 

[ba123]

How long it takes all depends on how bad the leak is.

As far as the idea of having it in there, you're not going to hurt anything. It's not an additive that's going to hurt something.

 

[Wild horse 75]

Looking at that I’d be tempted to pull that header and make sure you don’t have oil in there. A bad valve guide and seal on that exhaust valve won’t necessarily show up on the plug but you could still have liquid oil running out the port. And header gaskets aren’t oil proof so it’ll wick right through.

 

[spap]

Could the fan be blowing up oil from another direction ?

 

[kat]

Looking at that I’d be tempted to pull that header and make sure you don’t have oil in there. A bad valve guide and seal on that exhaust valve won’t necessarily show up on the plug but you could still have liquid oil running out the port. And header gaskets aren’t oil proof so it’ll wick right through.

I thought that too, but I have zero smoke coming out exhaust pipes.

 

[kat]

Could the fan be blowing up oil from another direction ?

I thought this too since after I clean everything off and let it sit and idle I cand see any leak. But if run it up the road it shows up. I've looked the best I could underneath but can't seem to see anything. I've even replaced the oil sensor and extension.