Just occurred to me, the dealer that says internal cleaning is a maintenance problem. Ask him to show you where in the recommended service schedule this procedure is listed. Ask him to show where this is part of the BMW service program included with the car oil changes.

As it does not exist, this dealer is specious. Just another case of MINI not owning up to their product.

 

Ok,as I have mentioned numerous times on other threads...I really believe the long interval oil changes that Mini perceives to be good on their maintenance schedules is totally tooooo long .I have an '07 46xxx mi. and have changed oil about 3-4000mi added techron plus every 3000 or so and the car purrrrrrrs.10,000 miles is far too long for oil changes.Talk to any mechanic (outside Mini) and they will tell you the same thing.Maybe I do oil changes too often,but I have never had a problem with the carbon issue. I'm certainly not pushing techron plus,but it has helped I believe with this issue....

 

First, to say it "has nothing to do with location in the country" is based on what? Second, Im not trying to gain information thru complicated sampling, it would just be nice to know where all of you with these issues live. As I said before, I know a few R56 owners in my area (Colorado in general) that have higher mileage cars--one 07s is approaching 80k--with no carbon buildup issues, and yes they have been checked.

Did anyone stop for a moment and consider that MINIs that run at higher altitudes (5,000 feet plus) are possibly not, or only minimally affected by this? After all Thumper Phoenix is only 1200 feet up, Vegas, Texas, etc even lower. If there are any owners in Albuquerque, SLC, or even Denver or Colorado in general that have this problem, they sure havent chimed in yet, and the only R56 serviced by my dealer for this issue was a transplant from back east.

 

Im 100% with you on this one, tvrg

 

It's a function of it being a direct-injection engine. Gas is introduced directly into the chamber by injectors, not by flowing over the intake valves.

 

Correct fishbert. So the gas won't coke into a sponge like it does in port injection cars. (See Shell commercials) That is not the question at hand.

Now for why we have buildup?
A few facts, or at least working facts:
SOMETHING is causing carbon buildup in the intake valves on the manifold side.
DI is not new. Mr. Diesel came up with it a long time ago. DI was used in WW2 in at least one German aero engine. Mini is not the only DI car out there.

The going theory is it is PVC route induced blow-by oil cokeing on the valves. Of course, our old stand buys of Techrilon or BG won/t clear this as the injectors do not spray the back of the valve. Supporting evidence is oil found inside the intercooler and manifold. This has caused a mini-industry in vapor separators ( catch cans).

Now WHY is this a problem on some cars, and not on others? Why do some get lots of oil in their catch cans, others nothing?

My hypothesis is the ring seating effecting oil control. Reason is up in the air which is why I asked for some feedback on break-in vs buildup. If there is some correlation, than that may add weight to the hypothesis. If there is none, we need another idea.

I suspect the regional aspect to be a red herring. Yes, fuel mixtures do change across the country and across seasons, but this would not seem to be a fuel problem.

 

The same thing can be said of the first gen cars.....some gets lots of oil in the OCC and some very little. Mine gets about 6oz's of gunk every 6 months or so. That would be a lot of oil gunk being sucked into the engine and getting deposited on the intake valves.

 

The first-gen isn't a direct injection engine, is it?
I would think that the fuel washing over it would limit build-up, as well as make it easier to remove whatever does stick there with a simple gas additive.

 

And its also not the only DI motor with carbon issues. It's a huge issue with almost all of the DI motors out there. This is NOT a new issue with any of these cars.

VW/Audi, Porsche, Lexus....all have widely documented issues with carbon build up. It's the design of the motor, plain and simple.

Why don't you guys buy the "no gas over valves" theory? Modern gas is full of additives/detergents which prevent carbon buildup. In addition the atomized gas mixture going over the valves cools them....this cooling aids in the prevention of carbon deposits hardening to the valves. The deposits harden/stick to the valves under the high heat that is present.

 

I meant the statement about OCC's. The amount caught in the cans varies greatly from car to car, including the 1st gen cars.

 

The postulations and pure speculation about intake valve carbon build up in this thread are a riot. The carbon build up problem is inherent to all direct fuel injection gas engines, not just the MINI. There are several SAE papers and abstracts on the subject and so far only Ford has tried to solve the problem. I'm not giving the paper titles, you have to do your own research. Dennis Simanaitis in Road & Track had a column sometime ago that condensed these papers into something understandable. Right now the only cure is a properly baffled OCC system and regular Seafoam treatments. Why the manufactures deny the problem is another major can of worms.

 

BG 44k ad next to this thread - go figure.

I run Chevron supreme, and only Chevron Supreme. Mobil 1 0W/40.

 

Not a coincidence. Google Ads at work.
http://www.npr.org/templates/story/s...ryId=129298003

 

No foolin' - I go on my diesel truck site now, and MINI ads always pop-up. Guess they don't know we already bought the MINI.

 

Ok...So we all know that D/I engines have been around for awhile and the problems still excists with carbon build up.Why then is it taking these auto manufacturers to figure out whats causing all these "hi-line" cars to gunk up vital engine parts,some with very low miles.I find it hard to believe that a solution in engine design has not been a resolve.Or is it actually in the design...debatable.

 

So what's an average MINI owner to do about the carbon buildup?

 

The answer BMW would like:
Sell your old MINI and buy a brand new one, of course!

 

Read all the posts in NAM's threads on Seafoam, OCC's and intake valve carbon build up. All the answers are there, just beware of the BS slingers!

 

The Seafoam is a definite must, but I've read some wild frequency recommendations. Everything from every 5000 miles to every 30,000 miles. I"m not a mechanic and it's difficult to figure out what is reasonable.

For what its worth, I drive mostly city, only about 3,500 miles a year and I change my oil every spring faithfully and I live in the Pacific NW.

Any Seafoam recommendation (as far as frequency)?

 

I do a single treatment just before every oil change or 6K miles and this seems to be solving the carbon problem. BTW, where you live has nothing to do with carbon build up. It's inherent to a DFI engine. However, how you drive does. The more you're on the boost, the faster the carbon build up due to the increased crankcase pressures blowing more phlegm through the PCV system.

 

Thanks for adding some common sense to this thread Dwight!

It's plain and simple....related to the design of the DFI engine. Pop the PCV line off while the motor is running and observe all of the vapor which comes out. It goes directly to the intake mani, and bakes onto the valves.

I love how these guys are trying to engineer new theories about it.

Another thing, MINI is very aware of the issue. The reason why they don't just add it to the maintenance program is $$. They do however, RECOMMEND that you pay for the carbon cleaning service. MINI is only responsible for the car up to 4yr/50k miles, so they aren't going to institute carbon cleanings as part of the maintenance services that come out of their pocket. As I said, if you want real info about any service issues, do not ask your SA's.....make friends with the techs. They are the ones that have the cars apart day in and day out, and have way more info than the SA's do.

 

Do MINI mod peeps do PCV reroutes? I knpw in the diesel truck world many do that and EGR block-offs as well DOC & DPF deletes.

 

+1 , i use 1/3 of a bottle every 4k since new

 

Indeed they do! I put my own system together using 42 Draft Design's baffled can and BSH's dual port boost tap to push all the PCV vapors through the can before entering the turbo intake. It works. The tubing downstream of the can is dry! After 10K miles there was about 2tbs of real nastiness in the can.

 

Agree. At least I do say these were theories. Very interesting if this is all DI engines. I am not a member of SAE, so I can't see their papers. So, what is the jest of the papers? Is it oil vapors or some other source? There must be some material that is being carbonized. Yes, not having gas additives to dissolve the deposits is a symptom. Why is this not a problem in diesels?

Now, it is back to what to do about it, and why some cars are much worse than others. I put forth a theory it is related to break-in and ring seating. All other theories are worth discussing.

Step one in problem solving is brainstorming where all theories are posted. Not laughed at. Then you look to see which ones have the best opportunity to research. Sometimes fishbone is used to organize ideas. So far, only one idea so that does not get us anywhere.

Step two is applying experience and related symptoms to identify which theories to peruse. Others have lent credence to crankcase vapors as the source of the carbonizing material in observing the amount of vapor coming through the PVC system. This would make blow-by a reasonable direction to investigate. Can anyone else think of other things that would make the amount of vapor, or the amount of blow-by, to vary car to car besides ring seal?

I offer a second theory: Oil leakage down the valve stem. Valve stem seals or guide fitment/wear. This seems doubtful on new engines, but it would not be the first time in history. ( remember the first Rabbit #4 exhaust guide crimp problem) It also sounds doubtful as it could be for this engine, but if this is a problem on many DI engines, I would not be looking there first.

Let's hear other theories. I would love to hear what Ford or Lexus thinks.