Help Needed Diagnosing Engine Fault
 

Hi All,

I was driving my E46 320i auto tourer 6 cylinder M54/M52TU back home the other day when the engine cut out as well as the power, roadside assistance said the top hose was dripping coolant on the drivebelt and that had made it slip cutting the power. They were right, the O Ring in the hose had gone. So I fixed this but the engine hasn't sounded the same since and the engine light on the dash stays on.

There's a whirring sound that gets more pronounced as the revs increase. Whilst idling the engine sounds OK. Sometimes I can hear a clear puffing sound like there's a small steam engine somewhere in my engine bay (exhaust manifold leak???). This is louder under the car than over the engine bay.

I did notice some 'white mayo' under the oil filler cap but I don't use the car that much - the engine did over heat about a year ago when the expansion tank split. There's no sign of 'mayo' in the expansion tank or dipstick, I also changed the valve cover gasket recently and there was no sign of 'mayo' in the valve cover. I did a compression test and all the pressure ratings are about 14 bar on all 6 cylinders. That said the 6th glow plug (most rearward) shows some signs of mayo although its dried on and doesn't seem fresh.

Lastly, I put a code reader to the OBD and have the following codes (some are symptomatic of me removing the DME relay and fuel pump fuse for the compression test):

7B Activation, Map Cooling
D1 Anti-tampering protection EWS
08 Signal, air-mass flow sensor
D9 Signal CAN EGS
35 Activation, idle speed control valve/opening coil
1B Activation, idle speed control valve/closing coil
64 Control units, self-test
25 main relay, switching delay
24 main relay
45 Activation fuel pump relay

Other codes that I had last week but seem to have disappeared since along with the puffing sound are.

4A Activation, A/C Compressor
7C Activation, solenoid valve, intake manifold (DISA)

I'm a bit lost as to what to try next and what to look for. If anyone has any suggestions on probable faults (car is 2004 with 116000 miles) or tips on what further diagnostic tests to run, they;d be gratefully received.

Thanks in advance.

Pete

I would look for water intrusion into the front electronics box. Also, unplug the thermostat and make sure there is no coolant seepage from the thermostat up into the wire harness. If you don't see anything at the harness for the thermostat it might be a good idea to open up the DME to see if there is any coolant that went in through the connectors into the DME.