Carbon build up on inlet valves

[peterhellawell]

Hi
I have an N18 engined Cooper S. I just wanted to know has any one
found carbon build up to be a problem with the new engine yet.
I've only done 9k so no problems. But I would like to know if it is going
to be a problem.

[cjm]

Type 'carbon inlet valve' into the NAM (northamericanmotoring.com) search box. There are threads on this issue.

Our US brothers tend to notice features about their MINIS earlier and share them more readily than we do. eg 'N18 supplementary sensor + cradle fix' and 'N18 oil-wicking issue'. (I've recently had both warranty 'fixes' after they've been identified via NAM.

Like you I have an N18. I keep my ear to the ground on NAM. Some seem to be buying oil (vapour) catch cans for their N14s and the consensus seems that N18s will suffer like any Direct Injection engine but slower than the N14.

Not too much data at present...

[peterhellawell]

Hi CJM
I've had the water temperature sender replaced, the new way, they seem to do it with new piping and an extension to the wireing harness as they introduce a new sensor to the system rather than using the one in the thermostat housing and the solanoid in the oil pump.
Also the mini centre caps in the alloy wheels as they were starting to lift slightly
from the edges (very slightly).

[cjm]

I'm a little concerned that I had to self-diagnose these 'enhancements' then use my elbows to persuade dealer attention.

I presume these significant issues wouldnt have been addressed for 2yrs/20000mls, if at all?

Due to this 'dealer fog' I feel the need to visit the forums to scavenge info...

Not thrilled with any of these observations TBH.

[peterhellawell]

I didn't know about any of these problems. I had read on the American
web sites that they had been changing thermostat housings and that it had
not worked or lasted long.
I had taken my mini in to the dealers for an over night stay so they could do
a cold start in the morning and tell me if the engine was making the correct
noises, they arnt the quietest of engines hot or cold.
They phoned me the next day to say the engine was making normal
sounds and that they had changed the oil pump solanoid and the coolant sender
fix. Which I thought was very good of them as I didn't even know about
the fixes for the UK.
I'm not sure if BMW / Mini Change things / fix them where other manufacturers
Just wait and see what happens?
I had two fiat coupe 20vt from new and never a problem or a recall !!!

[cjm]

I gather these might both be 'technical service bulletins' - kind of quiet 'enhancements' actioned when they next see your car. I understand the new 'coolant sensor + cradle' TSB was issued in the first week of Sept '12. My dealer hadn't heard of the 'oil wicking issue' 'til last Thurs. It might not yet be a TSB in UK.

As in my previous post, for you this could have been 2yrs/20000miles further down the road. IMO you were 'lucky' you had (different) problems before this, otherwise you'd have been limping along for a while not knowing of the 'fixes' under warranty.

There hasn't been any info volunteered from MINI has there? How many people don't know of these important 'fixes'? Again, concerning...

(BTW do you know if the new coolant sensor supports or replaces the old one? Plus, I found it difficult to remove and even more difficult to replace the oil filter cover after this fix due to 'stuff' laying on it/getting in the way.)

[peterhellawell]

Hi
The new coolant sensor replaces the old one. That's why there is an extension to the wiering harness as well as the piping.
I thought the piping looked to be in the way of the oil filter cap. Now you have to be wooried about them damaging the new filter when doing the service at the dealers. I always do early oil changes on my cars. But I am not convinced dealers are as carefull with things as the owners are.
I would have rather had a new thermostat housing with the new coolant sensor in it rather than this new piping. I don't think they could stop the corrosion on the sensor when it was in the thermostat housing. Says a lot for the corrosion inhibitor in the antifreeze.

[cjm]

Thanks for that info.
BTW there's a thread on NAM 'N18 Carbon Buildup' that unravelled today that's very appropriate to your thread here...

[peterhellawell]

Hi
I had a look at the thread on NAM 'N18 Carbon Buildup'
I thought the pictures showed a fairly clean inlet system.
I feel a bit relieved. Thanks for that.
If your interested in preventative maintenance. I've noticed
if you take the caps of the front struts you can see the top
strut mount bearings and there isn't much grease in there
so I think it may be worth putting some more grease in there
or at least watching to see when the grease goes hard and then
putting more in.

[cjm]

Yes but, cynically. more positive info will give more relief...
That susp bearing's a top tip! I'll do some prising later.
(You've 'coppaslipped' the alloy/hub interface and the disc nut, I bet. I've bought an R58/9 under-bonnet insulation mat as well. That's about it for me on the preventative side, so far. I heard some OEM plug missfire issues off NAM but that seems quiet now.)

[Dr Phoo]

Our November 2008 John Cooper Works required a top end strip down at 15000 miles due to excess carbon build-up on the inlet valves, cost £2460.Fortunately BMW ageed to pay for 100% of the parts and 80% of the labour as a goodwill gesture, which brought the cost down to £400.
This inlet valve carbon issue seems to be an inherent problem with the direct injection/turbocharged Prince engine and numerous similar cases have surfaced in the USA.I am not aware of known fix for this problem.Hardly fills one with confidence.

[Macguyvic]

Mini told me that the more ethanol they add to the gasoline the carbon billed up will continue.