(Sorry, not much of a grease monkey, so please be patient...)

What's involved with checking the intake valves for carbon?

I suspect that my car is having some intermittent issues possibly related to carbon build up, and I'd like my dealer to take a look, but they are reluctant to do much without being able to a) reproduce the issue on the spot, or b) see some kind of fault in the computer.

How much (ball park) should it cost me (in time and money) to have them physically look at the valves? And what work is involved with doing so?

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Note: I know a seafoam treatment is supposed to clean the intake valves, but I am still under warranty for a few months, and would also rather have some kind of definitive confirmation that carbon build up was (or was not) an issue.

 

I don't understand how carbon buildup could cause an intermittant issue, seems to be it would be progressive with the amount of buildup - if anthing. Let us know what you do and/or what they find.

To answer your question, they have to remove the intake manifold to see the intake valves.

 

well, what's discussed here pretty much describes my MCS's issue to a 'T'. Again, not much of a gear head... but people seem to keep coming around to a misfire that the ECU is stepping in to compensate for. It sounds as if one of the likely culprits is carbon build up.

I intend to check my plugs to see if the cylinder needs attention... but I also see a lot of internet chatter about direct-injection engines and carbon build up behind the intake valves (in the case of the "Prince" engine in the R56, likely due to oil from the Positive Crankcase Ventilation System (PCV)). Many are saying this is an issue with their cars in the 30-50k miles range (mine is around 41k miles).

So, I'm mainly trying to get a feel for how big a job it would be to get an eyeball on the intake valve stems. I'd like to find out their status... but I don't want to be the silly owner making unreasonable requests in the service bay.

Anyway... removing the intake manifold... is that ugly, time-consuming, and an action of last resort? Or is it just an hour or two of work? Maybe even something I can learn to do myself (or have a more engine-savvy friend help with)?

 

Also, try this thread for more info. Good luck!

 

Is your car still under warranty? Keep this in mind before you tell the dealer you found carbon on the valves or have them check for carbon:

-DIY maintenance, especially if you screw it up, may void your warranty.
-The MINI/BMW corporate position is that the carbon buildup is NOT an engine defect. It's considered a "maintenance issue". If there is no malfunction or CEL or anything and you show them carbon buildup, they will most likely tell you that you have to pay to clean it as maintenance. What's more, if you don't clean it and the engine later develops problems, they will not cover it due to "lack of maintenance".
-If there is plenty of warranty left or you plan to sell the car before the warranty expires, you might be better off keeping mum. If the engine develops problems later, you might be in a better position to assert a warranty claim by saying that you didn't know about the carbon buildup and MINI did not advise you about it.
-If you plan to keep the car a long time and you do find carbon buildup, consider just paying to have MINI clean the carbon deposits. That way if there is a future problem, you will be in a better position to claim that MINI was at fault. You don't want to give them any excuse to void a warranty claim.


Take a look down at the valves by either:

1) Using a borescope

2) Removing the intake manifold.

See post 23

https://www.northamericanmotoring.co...e-seafoam.html

It takes about 30-60 minutes the 1st time when you don't know exactly what you are doing and have to move all the hoses and stuff around. Go slow and make a note of everything you unscrew, remove so you can do it in reverse. Once you figure it out it takes about 15 minutes to do. IIRC the tools you will need are:

-ratchet w/ 17 mm socket for the 5 bolts holding the intake manifold
-torque wrench for re-torquing the bolts (I have no idea the torque setting)
-flat head screwdriver for loosening all the band clamps on the hoses and releasing the electrical plugs
-lights and small flashlight
-hand mirror to see down the ports
-Ben Gay for your sore back from bending over

 

The hex nuts on the manifold are 13mm and need to be torqued to 20Nm or 15ftlbs.

 

Great info! I appreciate it.

Yeah, the car is still under warranty, so I'm not going to do too much DIY fixing just yet. But I'd like to poke around some and see if I can find the root cause of my issue before the warranty runs out so it might help me make up my mind on an extended warranty (if it's a serious issue, I might… if it's just carbon build-up, I might not). Clock is ticking on that extended option.

 

for the $15 you spend, if you find that your problem is gone, then you know it was carbon! If it's not gone, then it's probably something else.

Anyway, it will take less time to do than getting to actually see the backs of the valves. And out of pocket is less than a couple Frappaccinos from Starbucks.

Matt

 

The problem is so sporadic, though, I don't know if something's really worked. It was about 3-4 weeks between instances this last time.

Besides, it would probably do me some good to poke around in there. Learn something new, ya know?