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View Full Version : Nasty oil leak at back of head.


billy in slo
06-22-2009, 10:29 AM
My 1990 535iA has developed a bad oil leak coming from the back of the head/block area. I can not see the source but it is not the valve cover, it runs down the exhaust side of the bell housing. With out looking at the car yet my shop is saying head gasket. Aren't there some other possible sources back there? I seem to recall some other "stuff" back there when I did a motor swap on my e12. Can't find a photo or schematic though. I just don't want to pay for a head removal/replacement if I don't have to.
Thanks.
billy in slo
Adnan
06-22-2009, 02:18 PM
My 1990 535iA has developed a bad oil leak coming from the back of the head/block area. I can not see the source but it is not the valve cover, it runs down the exhaust side of the bell housing. With out looking at the car yet my shop is saying head gasket. Aren't there some other possible sources back there? I seem to recall some other "stuff" back there when I did a motor swap on my e12. Can't find a photo or schematic though. I just don't want to pay for a head removal/replacement if I don't have to.
Thanks.
billy in slo

Hi,

This is from memory and so may be flawed but I recall a rectangular plate at the back of the head when I pulled the one off my M30 a few years ago. It probably has a gasket that has failed so see if you can get a mirror back there to check.

The second and far less likely possibility is that you have a leak from the oil filler cap. If so, it is likely to run down near the back of the manifold but it's a long shot.

Hope that helps,
Adnan
Martin in Bellevue
06-22-2009, 03:23 PM
Check the oil pressure sensor on the intake profile, near the firewall. The motor is tilted & the oil can drip to the exhaust side.
billy in slo
07-02-2009, 10:21 AM
Dude, you are my hero, it WAS the oil pressure sending unit. You saved me a ton of money!
Thank you, thank you, thankyou.
The darn thing was only hand tight.
This board is awesome.
ILoveMPower
07-07-2009, 01:36 PM
Just had the same problem with mine, it cracked and sent oil spewing everywhere, surely a scary thing when suddenly your oil pressure warning pops on!