Mini Dave's rite . Tear it down . At lest take the head of and check there frist .
I new I did not have carbon build up in the head , I drive the car to hard for that to happen and change oil to often.

 

First of all, as we all know MC have a direct port injection system which is different from the conventional Fuel injected systems. Being direct port the injectors inject fuel directly to combustion chamber. As opposed to the conventional Fuel injected systems which inject fuel directly onto the intake valves themselves. This results in sludge build up on the intake valves, that con rob you of a good amount of compression. The Seafoam applied through the intake can clean said sludge helping restore compression. However there are time that even seafoam won't help, And Yes the only way to fix is to remove the head. So don't think that just because you change the oil often this won't happen to you. Sludge on the intake valves is composed of Dust that got past the filter and soaked up with the Engine oil fumes, that come from the pcv valve. This is why seafoam works.

 

I think, though I'm not certain, that the R53's add the fuel to the air before it goes through the intake valve, thus keeping the intake valves fairly clean. The R56's have direct fuel injection which is why they get carbon build up on their intake valves. Nice thread resurrection though.

 

Port fuel injection is what is used on the R50/52/53 and G2 Coopers, the only cars that use direct injection are the G2 MCS.

Seafoam only works to an extent. If the carbon buildup has been coking for awhile you need to carbon blast the valves, it is the only way to properly clean the intake valves at that point. Once the valves have been blasted you can start doing a seafoam treatment every oil change to keep carbon deposits down. We always load the new DME update to cars we're carbon blasting as it has new software to help combat the buildup issues.

 

I have an 06 convertible. At 73,000 miles, engine light came on and required complete valve job for $4000. Now at 83,000 miles light came back on. Burnt valves again. Mechanic could not provide a reason why this is happening. He blamed fuel. I have not done anything to repair it yet. I would like to keep the car but won't unless I can get the root problem solved. Any insight in what is causing this? I did have a low speed cooling fan problem but installed the resistor as recommended in a different thread.