I have been doing some research on Minis for a few weeks. I have notice several threads on carbon build-up on the intake side (mainly of #4). I haven't read anything about a fix just yet (if there is one). I have notice that people are reporting the dealer blaming the problem on bad gas, and some people have kept all your gas receipts to prove them wrong. Anyways, my question is "Do the new (09-11) minis suffer from this carbon build-up?

 

The "bad gas" crap is not true, it's dealer BS.

The carbon buildup is going to happen on direct injection cars like ours. The only way to combat it is to install an oil catch can and route both ventilation outlets into the one can (like BSH does), and to do regular seafoam-type treatments.

I know that at 30000 miles, I'm taking my cylinder head off and cleaning the intake valves thoroughly

 

Yes, what Etalj said. "Bad gas" is a line from a script that MINI USA gives the dealers to dodge warranty work. From looking around this site, they use it for many different engine woes.

An oil catch can is the only fix I know of. Here is a real good thread about it,

https://www.northamericanmotoring.co...t-install.html

Dave

 

I reading this thread now about this issue and HHH points out a thread on MINI2, where a guy had his motor and turbo replaced, and I just finished reading the thread on MINI2 and the guy who had his turbo and motor replace, a year later posted he is having the same problems over again.

Here is the thread on MINI2 I was reading:

http://www.mini2.com/forum/second-ge...r-4300rpm.html

The thread on NAM:

https://www.northamericanmotoring.co...in-engine.html

 

The carbon build up on the intake valves is caused by the direct fuel injection on the engine. Most other cars have port injection where the fuel injector is in the intake manifold. Any oil that is introduced by the Positive Crankcase Ventilation system is washed off of the valves by the gasoline being injected into the air stream before the intake valves.

On a direct injection engine, the fuel is injected directly into the engine, right above the piston, bypassing the intake valves, that is why they have a high pressure fuel pump, to overcome the high pressure in the space over the piston.

The oil from the Positive Crankcase Ventilation system isn't washed off of the valves, like with a port injection system and the heat from the burning fuel in the combustion chamber cooks the oil mist onto the backs of the valves, where it builds up over time, causing cold start and rough idling problems.

The carbon buildup on the intake valves is not peculiar to second generation MINIs, it happens on all direct injection engines with Positive Crankcase ventilation.

Oil Catch Cans were originally developed to keep oil from the Positive crankcase Ventilation system out of the intercooler, where it builds up, reducing the cooling efficiency of the intercooler. And, for the benefit of engines with direct injection, they also keep oil out of the air stream going into the engine and prevent carbon build up on the backs of the intake valves.

Dave

 

Dave,

Have you had this problem on your 2010?

 

No, I put an oil catch can on it almost right away.

Dave

 

With 39,000 miles on my '08 MC, should I consider a seafoam treatment? I've heard about seafoam treatments, but have no idea what it actually is.

 

https://www.northamericanmotoring.co...t-r55-r56.html

I haven't done it, just what I've read here.

Dave

 

I have 1st gen and at every visit dealer ask what kind of gas I put and they really grilled me about it when they cleaned the injectors. But I told them that I ONLY put 91 Chevron and occasionally 91 Shell and that if they offered 94 I would ONLY put 94 octane. I just cannot see myself putting anything less, I am too attached to the GP, to me its not just a means of transport or an econo-box.

 

Do the justacoopers need this?

 

Thanks for the link, Dave. I know it can be avoided, but the term *hydro lock* frightens me...

 

I'm wondering if Way or any other third party has started to offer this direct intervention valve cleaning as a routine service. It'd likely be a money-maker with steady demand...

I'd love to do this, but can't/won't until there is definitive word on how the newly designed '11 PCV system operates. I think the OCC vendors are falling down on the job here right now. Certainly they are squandering the opportunity to corner the near-term market. I guess the set of '11 owners anxious to install an OCC doesn't create enough potential sales numbers in the grand scheme.

+1 Also, the evidence I've seen in the forums--based on actual before-and-after photos of the valves--is that SeaFoam treatments offer, at best, only fractional value along with a bit of increased risk of screwing something up.

 

I read, in another post here, that BSH was going to look into any differences in 2011 MINI Oil Catch Can installation. You could drop them a line and ask.

http://www.bshspeedshop.com/bshstore/

Dave

 

From what I have read on here, No only the S models have problems

 

Do you think MINIUSA secretly fixed this on the 2011 with the new valve cover or what look to be a different cover?

 

I've been bugging them to the point that they are probably starting to ignore me.

 

Any word let on the OCC gil-galad?