View Full Version : Oil residue in spark plug well, on spark plugs, and on piston heads
papa_g
11-26-2017, 06:14 PM
31497
Changed my VCG and upon taking out the spark plugs, this is what I see. I've cleaned the spark plugs so they should be good. Only 27k miles on them so didn't feel like replacing them.
I've read some threads on head gaskets, piston o-rings / seals. I hope it's something as easy as "change the VCG, and the remaining residue will burn off as the engine is running."
Appreciate your help.
papa_g
11-27-2017, 08:52 PM
Bump. Since writing this, I have done my best to clean the crud from the spark plug wells. Some one suggested a compression and leak down test on the cylinders...I am thinking maybe I will just put the valve cover and spark plugs back on and have a shop do some more in depth diagnostics later.
How many miles on this engine? Average mileage between oil changes?
Also, could you post the results of your leak down test, as well as if your mechanic performed it on a warm or cold engine? I've been searching online for leak-down results for the m54 and have had little luck. Thank you.
papa_g
11-28-2017, 09:20 PM
How many miles on this engine? Average mileage between oil changes?
Also, could you post the results of your leak down test, as well as if your mechanic performed it on a warm or cold engine? I've been searching online for leak-down results for the m54 and have had little luck. Thank you.
87k miles. I think average 10k between oil changes. If i get the compression or leak down test, I will post the results. Supposedly the lower limit for cylinder compression is 146 units (i dunno if its PSI or something else). On Youtube, 50skid does a nice compression and leak down test on his cold engine and posts the results + analyzes them, if you haven't seen that already.
I have also seen someones results for their M54 compression test, and it was between 200 & 210 for all 6 cylinders. I am assuming this was done hot.
Oli77
11-29-2017, 04:10 PM
Just curious, how do you know the oil was not leaking from above?
Sockethead
11-29-2017, 05:18 PM
IDK... it kinda looks like blow by from the plug not sealing...the plugs should be torqued to 18 ft lbs...
The piston looks pretty normal to me. If you pull your DISA valve and look inside the manifold, you'll see what I mean... it looks just like that thanks to the CCV system in these cars....
papa_g
11-29-2017, 07:09 PM
Just curious, how do you know the oil was not leaking from above?
To leak from above (from the crank case?), wouldn't it have to leak through the spark plugs and into the combustion chamber? The more I think about it, I think it maybe just carbon on the pistons. I will use the liqui moly fuel additive when everything else is in order; that with a new ccv system, hopefully things look and perform better over time.
IDK... it kinda looks like blow by from the plug not sealing...the plugs should be torqued to 18 ft lbs...
The piston looks pretty normal to me. If you pull your DISA valve and look inside the manifold, you'll see what I mean... it looks just like that thanks to the CCV system in these cars....
Thanks for that info. Torqued the plugs to spec after cleaning them. BTW, here is a link with pics of my plugs in case you want to see:
http://forum.e46fanatics.com/showthread.php?t=1191025&highlight=
I am replacing the CCV system next; parts are waiting in my garage. I took the DISA out in preparation, and yeah... beyond crusty :rofl
Decided to change out the o-ring while I'm at it with a fluorosilicone G.A.S. o-ring.
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