Oil Fouled Spark Plug -- non iridium suggestions?
 

Hi all.

My wife's 09 clubman keeps fouling the #4 plug. I pull it out and there is oil all over the electrode. All the other plugs are dry. I've looked for different plugs, but can't find one that isn't iridium. I want to try using a standard tip plug and see if it will behave better with the oil on it. Has anybody used a plug other than the iridium?

Also, how can I know where the oil is coming from?

Thanks,

Walter

do a compression test to verify sealed chamber.

Iridium spark plugs are the most resistant to fouling of any kind of spark plug. The small electrode in them is hotter and burns away deposits better than other spark plugs.

Best to find out why that one cylinder is fouling the spark plug. I agree, a compression test is a good place to start.

Thanks for the responses. I'll try to do a compression test this weekend.

I thought that because the filament was so small on the iridium plugs, it would be easier to foul.

Walter

Well, the clubbie has been sitting in the driveway except for quick trips to the store. It idles like crap if you drive beyond 2 miles -- but is ok while driving.
Anyway, I did a compression test and I have 175 on all 4 cylinders. I was going to do a leakdown test next, but haven't had the time to do it. Also, how do you get this to TDC since you can't see the top of the piston?? All other cars I have worked on you can see the piston through the spark plug hole.

your clubbie is a justa or turbo?

This is a good start with compression numbers. The next thing is to look for vacuum leaks. perhaps the oil seeps from the valve cover into the spark plug?

to get to TDC, you can use straws and better yet, there is a locking pin hole at the transmission bell housing near the exhaust. For Minis, it is 90 BTDC.

It is a 2009 justa.
I was getting oil in the plug hole so I changed the valve cover gasket a few months ago. It ran great for a few weeks and then the #4 plug started fouling.
I will try to do leakdown test next. Thanks.

Was the plug fouling before you changed the VCG? If not then that is likely your culprit. Go back and very deliberately check your work.

VCG? Really? How hard is it to write Valve Cover Gasket?

People making acronyms out of things drives me nuts, and it is bad technical writing.

I blame smart phones.:nod: