Hi guys, my dad's R56 has developed a number of issues. I pulled the following faults using a $10 OBD2 scanner from Amazon.



​​​​​​Most of my DIY experience comes from working on my W210 Mercedes-Benz, but using the codes I bought parts from FCP Euro and did following...

• I replaced the engine air filter and cleaned the MAFS with MAFS cleaner.
• I replaced the spark plugs.
• I replaced the leaking valve cover gasket.
• I replaced the thermostat.
• I replaced the water supply pipe because it broke at the water pump end. I believe that I retrieved all the fragments.
• That lead to me having to replace the intake manifold and throttle body gaskets.
• The ordeal led to me also having to replace the crankcase vent hose since it made cracking sounds trying to remove it.
• I used contact cleaner on all the connectors during reassembly.
• Refilled with MINI branded coolant.
• Replaced the heavily leaking oil drain plug, oil filter, and oil.

​​​​I haven't replaced the O2 sensor, I thought that maybe the contact cleaner would help because the connectors for the O2 sensors were pretty dirty.

​​​​I cleared the faults after the repairs, but I was disappointed to see both misfires return after all that work. I believe it's still in closed loop and checking from emissions readiness, so I don't know if the other faults will also come back.

​​​​​Something new is that the heater started working again, but then stopped working once more. I also noticed that coolant would now apparently spray out of the reservoir after a drive. I've bled the system through the bleeder screw on the thermostat repeatedly, so I don't understand this new issue. I don't think that the new thermostat is also bad, doubtful, but I don't know if the FACET brand is any good.

I've also powered the radiator fan manually with my power probe, but I've yet to see the car itself do it, my dad just doesn't drive the car that often to get a clearer picture of things.

Finally, could someone explain to me why the car gets extra rough if I remove the oil fill cap or dipstick while it's running?

I really appreciate the help, I feel a bit lost right now...

Edit: I haven't looked into the coils because if I momentarily disconnect any of them the car would get rough, so I assumed they were fine, but maybe that's too rudimentary. I'll switch the coils from cylinders 3/4 and 1/2 when I get the chance.

 

To get a better idea of the problem you really need a Mini specific code reader. The generic ones do not read the codes right on the Mini cooper. If you are anywhere near Panama City Beach, Florida I'd be glad to run your codes for free.

 

Thank you, but I'm all the way west in California lol

I have a Foxwell NT520 PRO with the 38 pin Benz adapter and Benz, Maybach, SMART, and Sprinter package, but I see that they charge $100 for a BMW 20 pin adapter and the BMW, MINI, and Rolls Royce addon package. At that price though, maybe there's another scanner that's natively BMW/MINI. Do you have any recommendations?

 

You don't need the pin adapter for the Mini. You can plug right into the OBD port under the dash.

If there is air in the heater core, it might be difficult to vent. I would keep trying to bleed through the vent screw. Make sure the heater is set to full heat, and the car has time to warm up fully.

This is a helpful site too:
https://bmwfault.codes/

 

I tried bleeding it today, but the car is getting worse. The new development is that cylinder 3 is no longer reacting. I swapped the plug and coil, but it makes no difference if I connect or disconnect the harness from cylinder 3 while the car is running. The scanner says that cylinder 3 is a current fault and cylinder 4 a pending fault, and cylinder 4 does react if I disconnect the coil. I tried inserting my endoscope while replacing the sparkplug but the piston head was too close to the top for me to get a better image, but I cant make heads or tails of it.

 

That looks like it may have some carbon build up.

maybe do a compression test to see how the cylinders compare

 

What is it about the camshaft position sensor that makes cylinder 3 react again? I unplugged one and the car idled and ran fine, if I plug it back in it will start get rough again after a while, and run well again if I disconnect it on the spot...

 

Hi Ricky X32,

I found the problem on my '07 MCS R56-N14 on the cylinder 3 misfire. I did everything that you had described above and found the true problem. Here are the photos of what my problem was.

Notice anything unusual?

 

Ahhhh Vanski, I Just put a 2012 Justa (N16) back together with the exact same problem only it was a cylinder 4 exhaust valve that was damaged.



Ricky, misfires on adjacent cylinders is not a good thing (think head gasket.)

You need to perform a leak-down test to help isolate the problem.

 

Woah Mkov608,

I don't know who has it worse. Yours or mine? Any idea as to why these exhaust valves are having issues? I never seen an intake valves do like this. What gives? Anyhoo, here's my valve that was taken out cylinder #3 this past summer.

 

MIckey at Pro Comp Machine shop says most likely it was bad gas, but I think it's too hard to tell. There are too many variables that you would need to monitor to see what's going on inside the cylinder before the valve fails. Perhaps Briggs and Stratton makes a better valve.

 

Bad gas? How and through what mechanism would that cause a valve to fail in this manner?

Far more likely a budget exhaust valve is the cause. BMW has, in the past, used relatively low cost materials for the valve in conjunction with a hard coat on the valve seating surface (of the valve) to create a valve.

Both valves pictured have a lot of erosion in the seat area.

I would be most interested to know what the seat width is for both of the valves pictured. Seat width is the width of the contact "band" the valve has with the seat in the head.

 

Bad gas could have many definitions. Improper octane rating causing pre-ignition or detonation. Contamination in the fuel (excessive amounts of ethanol). Ethanol and water contamination in fuel is well known.

 

None of what you've described would cause a valve to fail before a piston.
The extreme seat erosion is more consistent with poorly designed/manufactured valve.

 

Without a FEA we'll never know will we.