SIKE30 0 Report post Posted April 20, 2008 Hey guys afew weeks ago I did a compression test on my 318i m10 and it came up with 120psi on all cylinders. is 120 good or bad? the car drives fine and does not burn oil or anything. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted April 20, 2008 Hey guys afew weeks ago I did a compression test on my 318i m10 and it came up with 120psi on all cylinders. is 120 good or bad? the car drives fine and does not burn oil or anything. The reading is a bit low, but that would depend on the guage that your using and how you did it. 5% variation in M10 is acceptable, but nothing more than 5%. I wouldnt want a variation on a later model car though. Quote Share this post Link to post Share on other sites
SIKE30 0 Report post Posted April 20, 2008 Should I be worried about it? Because im not sure if the motor is worth taking apart again to do the rings. I took it apart 2 years ago while I was doing the head gasket and replaced the big end and main bearings and all gaskets. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted April 20, 2008 Should I be worried about it? Because im not sure if the motor is worth taking apart again to do the rings. I took it apart 2 years ago while I was doing the head gasket and replaced the big end and main bearings and all gaskets. If its not giving you any problems.....leave it It could just be the guage you used or the way you did it. We always loosen spark plugs, start car, remove spark plugs and do compression test with wide open throttle. This stops and carbon getting under a valve and giving a false reading. Try it at full throttle...you might get a better reading or try someone elses guage Quote Share this post Link to post Share on other sites
SIKE30 0 Report post Posted April 20, 2008 Sweet thank you ill try that method you suggested. one more question could this be the cause of the oil pressure light staying on for about 5 - 10 seconds when the car 1st starts? Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted April 21, 2008 (edited) one more question could this be the cause of the oil pressure light staying on for about 5 - 10 seconds when the car 1st starts? No..... put an oil pressure guage on and check the oil pressure or just put a new oil pressure switch on....could be the switch, especially if the switch is leaking Edited April 21, 2008 by botanymotorworx Quote Share this post Link to post Share on other sites
SIKE30 0 Report post Posted April 21, 2008 Ok cool ill do that aswell thank for your help. Quote Share this post Link to post Share on other sites
