Hi everyone,

First post - terrible introduction.

I have a bone stock 2009 R56 cooper (I think they're referred to as a JUSTA) with a manual transmission and 185,000 miles. I bought the car in February of 2015 and absolutely love it. I bought the car as I was finishing grad school with 162000 miles knowing that it would be cheap on gas and not terrible to drive. I've had a few e30s and an e46 before this and this car has totally blown my expectations out of the water. It is fantastic. Fun to drive, best thing in the world to park, great gas milage and up until now... reliable. In the year and a half that I've had it I've graduated, started a big-boy engineering job, got married, bought a house. I don't want to let this issue keep the car down.

However, a few months ago I started to have a rare intermittent issue. When the car was under heavier load (think 6th gear at 45 mph up a steep hill, nothing crazy) every once in a while there would be a power dip. This was rare and only happened once or twice in two months. Not a huge concern - I almost thought it was a slip of my foot or something. The car really didn't have any other issues until my wife had the car idle roughly for her when she was driving it one day and I checked the plugs - all were ok except for cylinder 3 - it was pretty dark (looked like oil fouling) and their was oil in the plug well. I replaced the set and the valve cover gasket and it was fine.

Fast forward to last month. I'm on a trip down to NYC (about 200 highway miles from my house) and right as I'm getting into the city I get a flashing check engine light. Misfire.

I get the car home and a buddy and I start to go through it. At first the misfire is only an issue when the car is cold, but it eventually gets worse and worse. We've checked the distributers, they're fine. Checked the compression: perfect. Leak down test: 5%. Pulled the intake manifold: valves look fine - no carbon build up. Checked injectors with a stethoscope: fine. Seafomed it twice, added a can to the oil and did 50 miles before changing the oil. We can't figure it out. Honestly the numbers from these tests were what I would expect out of a car with a third of my milage (185K). Then we do a dynamic compression test. Cylinder 3 isn't getting beyond 30 psi. All other cylinders are hitting 120 at idle.

Dynamic or "running" compression tests are done while the car is running, not just during crank. I'm explaining this because this was new to me

So here's where we are now: this has to be a valve issue - right?. The standard compression test and leak down test both show that the rings are fine. The injectors are working fine, replaced the plugs, swapped the distributers... the valves have to be sticking.

Has anyone else encountered this? I know my car has more than double the standard average.

So... I'm considering having the head rebuilt. Has anyone done this? I can try using ATF or another detergent-rich fluid in the oil, but I really don't want to keep driving around with a misfire and possibly cook the CAT and causing other issues at the expense of not fixing the actual issue. Any idea on cost of a rebuild? Overall experience pulling the head? There seems to be a ton of info out there for the Cooper S cars, but not so much for the Justas.

The reason why we're doing this ourselves is all but totally due to cost. The car has 185K miles - there is no way I'm going to pay a dealer $2000-$3000 for work to a car that is work maybe $4500 on a good day.

Any advice or input would be greatly appreciated!

 

I've rebuilt my '07 S, no experience with a Justa. With your 185K miles, be prepared for other damages when you get the head off , i.e., cylinder walls, pistons, maybe even bearings. You're gonna need some special tools, a good service manual (Bentley's is best, personal opinion), and lotsa patience. Once you ID the specific problem and estimate repair costs, consider a re-manufactured engine as an alternative. The head can be removed without pulling the entire drive train, as can rods and pistons. Gotta pull the engine for a re-bore, but then there's clutch, crank and transmission seals, etc, that SHOULD be replaced.

I wouldn't count on it being a "valve issue" --- I've read that leak-down tests are supposed to be checking valves also. Cyl #3 seems to be the most prone to failure, even in the "S" world, usually piston-related tho.

Talk with your local machine shop to get head rebuild costs --- labor varies widely across the country. I used a hi-performance head rebuilder for my head work, porting, valve seats, etc --- http://www.thumperheads.com --- one of the best in the country, based in FL. He might also work on Justa heads. Expect to pay 200 - $300 for gaskets and non-re-useable (stretch) bolts.

If you're really convinced it's a head problem, pull it and evaluate what you find. Don't worry about costs until then. The answer might be very obvious.

Good luck.

 

It might be worth getting a cheap inspection camera from Harbor Freight that you can put down into the spark plug hole to look for damage.

If it turns out to be the head (which it might not be) then for a car that has 185,000 miles, getting a low mileage used head from a totaled car is also an option if the price is right.


I'd do this first if you haven't already:

You said you checked the coil and injectors BUT Did you swap the coils around to see if the problem follows to the new cylinder? Same with the injectors. I would not be surprised if it was a clogged or failed injector.

 

I agree with cerenkov on trying the coils and injectors on different cylinders, but with the low compression (30 psi) ICallMyCarKate stated, it sounds like it is very likely a valve issue. Valves being the source of the problem would also explain why you didn't see anything doing leakdown/compression tests the first time around.

Take a look at car-part.com and contact a few of the salvage yards about cylinder heads. In my quick search I found heads going for a high of $2800 and a low of $450. Might be worth speaking to a few and see what condition their heads are in and getting a reasonably priced rebuilt one.

 

wow, I have only 48,000 miles on my 2010. You must drive ALOT!

Anyways, I agree with others on looking for remanufactured head, saves a lot of headache, and ensures all individual components are new instead of mixing old with new.

But pulling apart to inspect would be first step. As long as this isn't your DD (or only car) I would have head ready to order but not order until inspecting everything there.

Also the suggestion about moving coil/injector to different cylinder is a good one.

 

I had a similar issue with my 2010 S. it turned out that the valves were hit on 1 and 3. the car started and ran for few seconds and the smell was baaaad. At any rate, if this is a pressure issue and based on the leak down test, i would think it is the valve. However, I would do two things:
1- Take off the head cover and feel the rockers for any gaps. if yes, the valve is bent. if no see 2.
2- check the timing of the car. if the timing is off, re-time it. if all is good, check the solenoid valve, they could be clogged and messing the timing but not to the point where they hit the cylinder.

are there any smells coming out of the engine or smoke?

 

Thank you all for the replies!

Switching the coils is a good suggestion - I should have already listed that we did that.
--> Checking the coils was what led us to check compression, do the leak down test and then the running compression test. We didn't directly check the injectors (we used a stethoscope, didn't switch them around) due to the fact that the running compression test came back so poorly.

No bad smells or smoke. Just has a rough idle, misfire once it gets hot and on the super rare occasion will die at a stop light.

I daily the car when I'm in town - I travel for work about 50% of the time and my wife has her own car, so I can afford to have it down for a few weeks. The big thing is that I'll be doing the work at a friend's house (he has way more tools) and I don't want to use up his space for a long duration of time.

I've driven 21K miles since I bought the car about 18 months or so ago. The woman who owned it before me had a pretty insane commute. The only work I've had to do up to this point was the exhaust solenoid, water pump and pipe, valve cover gasket and fix a water leak from where the old roof rack had been installed.

We'll check the timing and the rockers - we already checked them once, but it won't hurt to do it again. I'm pretty sure it's not the timing though due to the fact that it's only cylinder three.

 

Be aware that removing / installing injectors requires a very special tool. Whether swapping heads or sending one off to a machine shop, you'll need this tool, or access to a shop that has one. And, get the Bentley manual --- torque sequence / limits, stretch-bolt ID, and timing process if nothing else. Then, for illustrated parts breakdown, there's this site --- http://www.realoem.com/bmw/enUS/select --- you'll need the last 7 - 8 characters of your VIN to get in, but it's FOC.

I like the idea of buying a remanufactured head --- it's quicker and you might be able to sell the original, if it's repairable. There's a small market for those of us that want to port / relieve the head for better performance. But, as mentioned earlier, make sure there's nothing wrong with the lower half of the engine BEFORE investing a bundle.

 

Do you need the special tool for the low pressure N12 injectors?

 

OOPS! My Bad! Good catch Cerenkov, this special tool is required for turbo versions and their teflon seals, not the non-turbo version.

Let this be a lesson for ICallMyCarKate and other "newbies" --- info on this and any other forum should not be taken literally. I should probably keep my comments limited to what I'm most familiar with N14 & R56.

 

So, on another vehicle, it had a rough idle, never died while stopped, but felt like it was going to die a couple times. I could tell I had a loss of power at speed because accel. and top speed was noticable (like I was down 1 cylinder). Ended up being a broken valve lifter.

Sounds like you are having similar issues. I'm sure when you take off head you will notice something right away.