Hello,
My n52 engine is burning 1L per 600kms. It is smoking under acceleration. I've replaced the ccv/oil separator and this had not helped. Compression test shows all cylinders above 165psi which is normally and leaves the issue to point to the valve seals.
I am mechanically inclined and am looking for a DIY tutorial to do the valve seals while the head is still on the car to save some time. I've searched everywhere and cannot find the procedure for doing it with the head on the car for the n52 e90. I know I can take the head off and get it fixed at a machine shop but would take a lot more time and money.
Any DIY tutorial, list of tools, steps to take for my issue would be appreciated
Thanks,
It would be interesting to see what the crank case vacuum measurement is at
Crankcase vacuum should be 3-6 inches (umm, ~7.5 to 15 cm) of WATER , not mercury.
Is there significant oil in your intake manifold? Did you replace the brittle plastic CCV pipes when you changed the oil separator?
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
ace, how many miles in your typical trip? That is, do you drive the car primarily on short trips? I think you’d be better off doing more diagnosing before you start doing a major engine job such as valve seals. Btw, are there any oil leaking from the engine? How many miles on the clock?
There is no (or very little oil) in the intake. All plastic ccv pipes were replaced.
- - - Updated - - -
Typical trip are 5-25 kilometers, Half city half hwy. No oil leaks, car has 110,000kms.
Here's how to make a slack-tube manometer at home:
https://www.bimmerforums.com/forum/s...lacement/page8 (post #183)
Here's the electronic manometer I now own:
http://www.testequipmentdepot.com/ue...hoCTW4QAvD_BwE
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Found my issue, its not the valve seals. I pulled the plugs, cylinder 3 spark plug was black and caked in burnt oil. This led me to believe the pistons oil/compression rings were stuck. So I put a two ounces mixture of half ATF and half fuel injector cleaner in the cylinder for 24 hours, turned the engine over at the crank a bit then added more and waited another 24 hours. I stuck an endoscope down there and you could see the carbon coming off the rings onto the cylinder walls. Started it up and it smoked for a good 30 minutes but all is good now. It doesn't even smoke at all now when at idle, or on acceleration like before. I think I got lucky. Thanks for the help.
Edit - i was wrong! Will post more exploration below.
Last edited by ace309; 12-10-2018 at 04:15 PM.
Interesting solution. Some folks do the same thing with GM Top End Cleaner. The stuff is available on Amazon.
Actually, after a few weeks of use. Car is still burning oil, same amount as before. About 1L per 500kms. No leaks and doesn't smoke as I can see. Looking into testing your vacuum method, already ordered a few items to try it out. Will update in a few weeks after christmas.
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