I have a 2002 Mini Cooper S. The other day I was driving home up a step hill and the #2 cylinder stopped firing. A short distance later it came back and I was running fine. I went the whole weekend without any problems. The next that Monday coming home from work I hit the same hill and almost at the exact same spot #2 stopped firing again but again a short distance later it came back. This happened 3 times and the 3rd and last time the #2 cylinder never came back. I brought the vehicle to my mechanic who is a BMW specialist. he did a check for compression and it read 0. He indicated that more than likely a valve is stuck open in that cylinder based on the prior behavior of the vehicle. I really don't want to spend the money on a valve job the vehicle has 150,000 miles on it. It is only worth about $4,000.00. Is their something I can do first or try before I have to take the head or intake manifold off. I am mechanically inclined and now have the vehicle in my possession. Will Seafoam through the vacuum line work or getting a direct injection treatment from an authorized BD mechanic help. I also heard of walnut blasting through the intake manifold. I believe based on the cars behavior that a piece of carbon maybe stuck keeping the valve from seating properly. Does anyone have any thoughts on this. Any help is appreciated.

 

You should have a leak down test as that will narrow it down for you if you have valve issues.

 

02-06 is not direct injected like the R 56 so doing is seafoam treatment won't help.

 

Most of the "ideas" you have to work on the issue are stuff done on gen2 cars....different motor, different issues. The r53 tends to be pretty relilable, and carbon is generally NOT an issue...
If you din't want to spend $$....why do a bunch if testing to narrow it down....sounds like you have a decent shop who has an idea what to do....more tests are a $$ hole, spending $$ that could be used to FIX the issue.
Zero on a compression is pretty severe...more than a stuck ring...imo likly a true mechanical issue...150,000 is not super high for miles...sounds like the shop knows his stuff...i would be inclined to trust the mechanic with the hands on time...ask them for a guesstimate for $$ to pull the head..might be less than you think....and you might be kinda due, relibility wise for a new gasket, which you will get when it is reinstalled. The repair .....well if it is the valve, ONE can be done to save $$ or do them all and freshen stuff up to prevent future issues....
As it sits, with a dead, 0 psi cylinder, the cars not gonna go far/last long, so time to spend s few $$. Sorry, but crap happens....
Good luck!