Follow-up question: Does changing the oil more often help alleviate the build-up problem? I just talked to a MINI shop (not a dealer). He said it would help. Not sure I believe him, though. Thoughts?

 

Yes it will, when the oil gets old it starts to gunk up. This would then go into the engine to be burned, clean oil entering the engine is prefered rather than old oil!

 

Update... After submitting a less than favorable responds to a "how did we do" email from the dealer, I was contacted and they performed the entire service at no charge. Mini is running great and I couldn't be happier. Guess customer service is still a priority to some dealers.

 

No! Changing the oil more often will not reduce carbon build up. How clean your oil is has nothing to do with the buildup of carbon on the backs of the intake valves.

Our MINI's have a carbon build up problem because they have direct injected engines, in which the fuel is sprayed directly into the cylinders, rather than into the intake manifold, like many other (port injected) cars.

On port injected cars, oil from the PCV system is washed off of the backs of the intake valves during normal operation. On our direct injected cars, fuel never come in contact with the backs of the intake valves, the oil mist from the PCV system sticks to the backs of the intake valves and burns, leaving a carbon residue. This slowly builds up, until the carbon residue impedes the flow of air into the cylinders, causing reduced performance.

This is also why the kind if gasoline you use has nothing to do with carbon buildup.

This has been discussed many times here on these forums, the search function is your friend.

Dave

 

I hear what you are saying and understand it fully, but can't help but wonder if dirty oil would leave more deposit than clean oil. Maybe Systemlord is onto something.

 

If your oil is getting "gunked up", you are not even following the too long factory oil change recommendations and will have worse problems than carbon build up.

The amount of particulate matter in the PCV oil mist is close to, if not zero anyway.

Dave

 

was your 09 out of warranty ? Cuz they damn well better be doing this as a warranty item if still in warranty, it is surely a design flaw or manufacture defect.

I'm going to buy a scope to check both of mine periodically to make sure it gets done before the 4yr/50K is up.

 

Okay, the dirty oil theory sounded good but it also makes sense that not much particulate matter would be in an oil mist. I do change my oil once mid cycle at my own cost so mine gets changes every 4500 to 4700 miles.

 

I scoped my valves and had pictures showing heavy build up before my warranty expired. I showed them to the dealer. The dealer would not walnut blast my valves since my car was not throwing any fault codes. I cleaned the valves myself and engine performance was significantly improved.

 

Was it scoping your valves mean? Is that where you remove the spark plugs and insert a wire/camera? I would like to buy something like that so I can see inside the combustion chamber.

 

Not "scoop", but "scope". As in, "borescope". Or "tiny camera you can put into tight spaces and have a look around". You might be able to see something from inside the chamber, but to see the real buildup, you'd want to go through the intake.

Something like might work.

 

Not sure if this is applicable but it might help some. One of the things I picked up over the years was to never use the same gas stations gas on a regular basis. Switch from BP to Getty to Irving and so on. Apparently every distributer uses different formulations to give them a market edge. However in these formulations you might get a buildup of X compound if used on a regular basis while Y compound may dissolve x compound. Keep using Y compound and Z would remove it. This theory would hold weight to why one new type of gas would run like crap....it is dissolving all the buildup and contaminating the mixture.

Techron....sold as a mini factory fuel system cleaner is one such compound found in pump gas.

Another is to never use a gas station when it is being filled.

 

10/29/13-Cooper wouldn't crank after sitting for five days during my vacation. Towed to Hendrick Mini in Charlotte NC

2007 Cooper with 74,000 miles
1.6L SOHC
Dealer cleansed Intake Valves and replaced Cylinder Head cover: labor and parts $970.37 (10% off labor and parts, deducted from the 970.37).
Oil Supply line replaced free due to a recall

 

Lord have mercy, I wouldn't have taken it to the dealer, no way, no how. That's a super steep price at $1k. But glad you got it fixed at least.

 

Wouldn't crank? That doesn't sound like a carbon problem to me! More like a starter or a battery problem... If it were my car, I would make them explain to me in detail how carbon in the intake ports could keep the starter from even cranking before I would let them do anything to the car.

I hope you don't have the exact same problem in a few days.

 

I've got an '04 Cooper S 6 speed with 122k on the clock. I've done 2 rounds of seafoam, and the best I can manage is 28 avg mpg. I know this car can do more than that. The first round of seafoam gave me a few puffs of black smoke. Next round gave me a steady steam of grey. Mpgs haven't increased at all. Feels like it runs smoother and is in general more lively, but admittedly, this could be placebo. Will more seafoam do the trick over time? I know I should easily be getting at least 30, right?

 

28-30mpg????????????
You obviously don't use the fun factor pedal enough!!!! lol! You bought this car for mileage???? Get a Ford Focus own the mini for the experience.

 

I read all the posts in this thread about the carbon build up but there's one thing I'm not clear on. Is this problem mostly related to turbo models, vs supercharged ones? or is it across the board. I feel that most of the posters are S owners and newer ones at that, although I didn't bother to do an actual count!

 

it's both.
Supercharger and Turbo.

 

I have had my MCS for 9 years and never in all that time did I hit 30 mpg. If you are getting 28 regularly that is doing REALLY well. Just out of curiosity, why would you think that you would be getting at least 30?

 

There is only one way to get rid of the carbon build-up that completely removes all of the carbon build-up, that's with a walnut blasting. You don't have to take it to the dealer either.

 

The carbon build up problem occurs only on direct injected models. That means series two Cooper S cars.

Supercharged series one cars and non-S models don't have the problem as they are port injected, not direct injected.

Dave

 

Your model is not having the same carbon issue as the 2nd Gen cars. Your car is port fuel injected, not DI..

 

(((( There is only one way to get rid of the carbon build-up that completely removes all of the carbon build-up, that's with a walnut blasting. You don't have to take it to the dealer either.)))

Uuuuuh..... No there are more ways.
Intake induction cleaning with fogging system and proper chemicals.

 

Uhhh.

No. This is not your run of the mill intake sludge.

Long overnight soaks in sea-foam/combustion chamber cleaners don't help.

The fogging systems are designed to slow the buildup, but do nothing once it's truly set in.

You must media blast for proper cleaning.