The head plug on my 2007 S40 appears to be leaking again -- a slow leak that first appears on the engine bolt just to the left of the exhaust port. I had it replace at 9,000 miles, now at 15,000. Because it's tiny, and because I don't really want to spend the $$$ the stealership will charge to replace it again and am not up to the task of doing it myself, I'm considering trying a seal rejuvenator like this to see if it expands the plug enough to stop this small leak: https://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM?ie=UTF8&...

Several Amazon users have put it in motorcycles with no ill effects. My only real concern is the wet clutch. It's not petroleum based, and the reviews on Amazon make it seem safe. Anyone tried this, and if not, have any ideas about whether it will affect the clutch?

By the way, one of the bikes that the Amazon user put this sealer in was a 1993 Kawasaki Voyager XII. I have not idea how they are built, though since the head plug is plastic and not rubber, it's a moot point.

Thanks,
David

I agree with Norm,I would be leery ,the motor cycles your talking about may have been Harley's which have separate motors and tranys  which would allow use in their motors.If you had a shop do your last plug they didn't put sealer around it because their manual doesn't call for it ,and it leaking again. You really should do it yourself ,100"s of us have .

Thanks for all your responses so far.

I'm not totally sure that it's the head plug. If I clean the oil up with carb cleaner and then look at it after a short run, I see oil on the nut/bolt that you can see if you look into the hole in the cylinder block next to the exhaust port. Is the head plug directly over this bolt? If so, how can I tell for sure if the oil is coming from the head plug or from the nut being loose? If it's from the nut and not the head plug, will I have to remove the head cover anyway to retorque it?

I know many people on this board have replaced the head plug, but reading through the threads on the job, I find it daunting. Just replacing the cam chain tensioner with the verslavvy took me several hours, and this looks like a much more complex job. Or am I overestimating its difficulty?

Thanks again,
David

PS: I ordered the Verslagen head plug. Thanks, I didn't know these had gone beyond "experimental."

How can I tell, before I resort to pulling things apart, whether the leak is from the head plug or the cylinder nut undernearth it?

Good idea, using a piece of cloth. Sprayed the area down again with carb cleaner, will do a short run tomorrow.

If it's the head plug, I'll try the RTV-on-the bottom trick as a short-term fix. Any idea what the other member used to spread the sealant? Too cramped to get a finger in there, but you'd need to get it to adhere to the plug bottom and surrounding metal with no gaps.

The plug bottom is flush with the metal around it. Should it be?

Thanks,

David

If you can get a syringe with a curved tip....fill it with the RTV and apply it where you need it.  Or a syringe with a piece of tubing on the end....you may need somebody to squeeze the syringe while you carefully operate the tube end.

A follow-up:

I did the rag-in-hole test Dave suggested and found very little oil leaking this time. Then I thought: carb cleaner melts plastic and the "rubber" head plug, Dave said, is mostly plastic. I wonder if some of it wicked into the spaces where the plug was leaking and melted a seal. So, with nothing to lose, I sprayed the heck out of it with carb cleaner, waited a couple of days, and took it out for another ride with a rag in the hole to catch any drips. Not a drop!

It seems unlikely this "carb cleaner fix" for the head plug leak will last indefinitely, but until it leaks again, I don't see much reason to tear things apart. Versy head plug is on the way, so I'll have it when I need it.

Thanks for all your advice!

David

>> I wonder if some of it wicked into the spaces where the plug was leaking and melted a seal. So, with nothing to lose, I sprayed the heck out of it with carb cleaner, waited a couple of days,

COOL - thanks, I will try this.  Not ready for any bike surgery, but it would be nice if the fins would stay clean for a while.