Changing Con Rod bearings with Engine in the Car?

[NZ00Z3 187]

Hi

Car:
- 2000 E46 323i (M52TUB25 engine)
- 120,000 km

Symptoms:
- Slight dull knock from engine at idle
- Cylinder 6 is off the scale (1.5 to 2) on INPA rough running graph, all others are very even (<0.5).

Expected cause:
- Run big end (con rod) bearing on #6

Question:
- How hard is it to remove the sump (oil pan) and replace the big end (con rod) bearings with the engine still in the car?

Thanks in advance.

[zero 1162]

I cant tell you about the rod bearing replacement, but I can tell you about sump removal.

Its a bit of a pain as the engine has to be supported and then the whole subframe dropped to remove the pan. After that it will need a wheel alignment, so it makes sense to replace the control arm bushes (common wear item) at the same time.

I didn't think rod bearing failure was common on these engines, but someone more knowledgeable will be able to chime in hopefully.

[gjm 3258]

I know this engine can use oil as it gets older and the piston rings wear, but haven't heard of big end issues (before).

[NZ00Z3 187]

The plugs were recently replaced and they were checked over the weekend to confirm that they are still tight then removed to check condition.  They all looked good.

Edited May 11, 2017 by NZ00Z3