Cylinder head plug (camshaft end plug) pushing out
 

Last Sunday I spent the day doing the car control clinic and autocross tuneup Peachstate PCA held at Atlanta Motor Speedway in my 99 Boxster. A couple of days later i noticed smoke under throttle while driving home from work, and when I got it on jackstands determined that the lower camshaft end plug on the passenger side had pushed out some. I pushed it back into place, verified the oil level was acceptable, started it up and looked for leaks. No issues at idle, but when I had my helper rev it to 2500 rpm it started pushing out. Note the smoke was from oil hitting the headers, and was not coming out of the exhaust.

Got a new plug and replaced it this afternoon, and it looked fine until I had my helper hold 3000 rpm, at that point it started pushing out again.

When I pulled the old plug out, I noticed that someone (previous owner's mechanic?) had used a sealer on the plug. The outside had sealer covering it, and there was sealer on the "threads" of the plug, too. It looked the same as the sealer that was used on the cylinder head, based on what I could see at the seams of the head and cover.

I've looked into what could cause this and found the excessive sealant on the head covers could restrict oil flow in the channels. I've had the car over a year and put about 4,000 miles on it, and this is the first time I've had a leak at this location (or any other, for that matter). Last weekend is the hardest I've run the car, with a lot of runs into the 5000+ rpm range. but I've done a few interstate trips over the past year with extended periods of time between 3500 and 4000 rpm, and it seems to me if it was an oil channel blocked by someone using too much sealant on the head covers that this problem would have presented itself earlier.

This makes my wonder if either something may have dislodged, like the sealant used on the plug, and is now blocking one of these channels, or if there is some other item I need to be looking at. I see a head cover removal in my near future, and want to make sure I check all the possibilities while I'm at it. Any thoughts are much appreciated.

Thanks
Brian
99 Boxster
89 Carrera

You may have ejected the metal plug at the end of the camshaft. If this happens it floods the cavity with oil and the plug wants to eject.

Has someone recently sealed your cam covers?

I think you hit the nail on the head. Whoever worked on that car in the past used too much sealant. My guess would be a glob of sealant has broken loose and is blocking the oil return passage in the valve cover.

Thanks for the quick replies guys.

Jake, it has not been open since I've owned the car, so at least 13 months, likely much longer. If that plug you mentioned came out, I take it that is something I would see when I pull the head cover?

James, that's what I'm hoping, because it both explains why I've not had issues before now and would be relatively easy to identify and correct.

Brian

OP,
The end of the cam shaft is hollow, and the metal plug Jake refers to is metal like a bottle cap (but no wrinkles around the edge), pressed in with the cup end towards you. It should be totally solid.

As mentioned, there are a fair number of incidents where squeezed out sealant ends up plugging a passage, and your situation comes up.

Do NOT just remove that cam cover as the cover serves as the bearing cap (and bearing) for the cams. Spring pressure from the variocam tensioner will pop the cams out of place. You need the tool which mounts to the head and holds the cams through those holes where the plastic plugs are before you remove the fasteners which hold the cam cover on.

I have an extra tool I made if you need one. Just PM me an address and it's yours.

Thanks for the offer, flaps, I'm in the process of scoping out what all I need to do, it's likely I'll be in touch. I want to make sure I have all of the things I'm need to check covered before I get into this. As you can imagine, I only want to go through this once...
Thanks
Brian