Hi there Mini fans,


I love my R53 and this forum has been a HUGE help to me over the last few years. Thanks to everyone.

I've never posted before but I thought this fix deserved a first post to assist people in the future. Seems I can confirm what some people have found to be a problem with their Mini - although this seems a little more common in R50's judging by forum postings. Perhaps we may see it more often as our miles go up.

Anyway - the symptoms: DSC Light comes on when warm and at idle, power seems mostly OK at revs, sudden oil consumption increase, coolant may be disappearing.

Initial checks/tests/head scratching:
Replaced oil and filter
Cleaned and re-oiled air filter (seemed a little over oiled...)
Checked BPV - turned out to be perfectly adjusted!
Cleaned and checked vacuum related bits
Ran a few bottles of injector cleaner/booster
Checked plugs and leads (put stock leads back on)
Replaced cam chain tensioner - there's a lot of talk about this - seemed to help a little but was probably a good thing to do regardless.
Disconnected battery for a while... well... worth a try right!
Removed and cleaned ALL wheel sensors and added di-electric grease to the connectors

Yes... it has been about 3-4 weeks since the problem began. Please now cover your eyes - I have probably driven 2,000+ kms in this state!! Definitely not something I would recommend to anyone but sorry... I gotta earn a livin :-)

Even worse, I am trying to sell my baby because work is moving me from Australia to San Francisco in a month or so.

In the end I was reading a lot about people replacing EVERYTHING from coil packs, plugs, computers, etc, etc. I decided the only thing to do was try a compression test - like many people I think I liked the idea of some peripheral problem and doing a compression check may reveal some bigger, scary issue... so we avoid the compression check like a prostate exam!

What pushed me over? I finally coughed up the $80 to have my computer scanned at BMW expecting to find which wheel speed sensor had failed. Turns out, among a bunch of codes, was the dreaded misfire codes on cylinders 2 and 4. Dang! Time to buy a compression tester.

Sure enough - cylinder 2 had about 1/3 the compression of the others. Oh no. Next scary bit - try a little oil in the cylinder and re-run the test. No big change in compression so it's 'probably' not a piston. Hopefully just a burnt exhaust valve... as per some other postings I found after A LOT of searching.

Time to take off the head. It's been a while! Started taking things apart and finally the moment of truth - off comes the head. First look as I lifted it showed nothing too bad in the cylinders but as soon as I flipped the head over - there is was! One of the cylinder 2 exhaust valves was TOAST. A small piece missing on the rim turned out to be a BIG chunk missing when I removed the valve and could see the other side.

With 135,000 kms on the clock, the honing marks were still looking great in the cylinders. No glazing. I feel confident that the pistons and rings are still in good shape. Fingers crossed.

So, after finding an aftermarket valve supplier I should be picking up a replacement valve and head gasket today. A genuine valve was going to be 4x the price and 6 weeks ex-Germany from the local BMW.

If only I was keeping her - this would have been the perfect excuse for an upgraded head, cam, bolts, etc. Alas.

All the existing valves have been re-lapped and I've inspected everything else I can. Re-assembly will commence in a couple of hours. I will post the results.

Thanks again,
-Pete

PS: What do I think caused it? I have a couple of theories but one of them is that some of the excess air filter oil made its way into the combustion chamber and caused a hot spot or similar problem. I know this sounds WAY off put this is a pretty weird failure. Alternatively, it was just a manufacturing fault or perhaps a result of running generally too rich with my mods and no re-map. I also drive pretty hard so let's face - these things happen.


Search Terms:
DSC Light comes on when warm and at idle
TPM light comes on occassionally
My Mini sounds like a Subaru
My Mini sounds like a truck
I've replaced everything, now what?
Wheel sensor clean didn't work
Chain tensioner problem - replaced and no improvement
Over oiled air filter problem
Head gasket problem?

Mods:
Alta intake inc. silicone hoses
M7 catch can
17% pulley
GP intercooler w/ Water Spray
Stainless headers and 2.5" mandrel bend exhaust
Plugs and leads
(Always run on 98 octane fuel)

Other Problems I've encountered:
Power steering pump - fixed (not so fun but this forum helped!!)
LHS window regulator - haven't fixed this yet. RHS occassionally needs a "bump"
Air bag light - haven't got to this yet - I expect it is the "short cable" on the LHS (passenger side in Australia)