M54 Oil Leak-- Front of Motor

[kayger12]

I've been chasing down an oil leak at the front of motor for a few weeks now.

First sign was real subtle-- you know, the whole front of the vanos was completely covered in semi-cooked on oil (sorry, no pic).

I also found some oil on the top of the lower coolant hose.


I cleaned the vanos and surrounding area up really well and drove for a couple of weeks. After some research, my leading candidates were a leaking vanos exhaust solenoid or a leaking exhaust camshaft position sensor.

Pulled the radiator fan today to snoop around. VCG looked good, but I could already see some oil building up underneath it.


Looked down a little lower and found this (picture taken looking up from underneath the exhaust cps):


So I'm thinking the o-ring on the exhaust cps is bad. I'm heading to the stealer in about 5 minutes to pick one up.

Will install tomorrow and report back.

[danewilson77]

Could be KG. Inspect the old one when you pull it out.

[kayger12]

Could be KG. Inspect the old one when you pull it out.

Anything else you can think of?

I picked up the o-ring for 2 bucks.

Sent with Droid Fighter envy

[danewilson77]

Naaa...I think you're on the right track. It just tough....because if there a drip coming from the VCG....it can go down, collect, and coagulate somewhere, making you think the leak is somewhere.....it isn't.

I am in favor of the CPS o-ring....clean it up good, run it a while....and see what you got. Are you having noticeable "Oil Level" issues?

[Newjack]

There is a fastner that bently says is a one time use item and needs to be replaced after it is removed. It is the fastner (looks like a bolt) that holds the CPS in place. You can probably use it again but you might as well grab a new one if you can. Also torque to 7 ft-lbs.

[kayger12]

Naaa...I think you're on the right track. It just tough....because if there a drip coming from the VCG....it can go down, collect, and coagulate somewhere, making you think the leak is somewhere.....it isn't.

I am in favor of the CPS o-ring....clean it up good, run it a while....and see what you got. Are you having noticeable "Oil Level" issues?

No other oil level issues. VCG is only 13 months/12k miles old so figuring that it's good. The area immediately below the vcg looks dry, fwiw.

There is a fastner that bently says is a one time use item and needs to be replaced after it is removed. It is the fastner (looks like a bolt) that holds the CPS in place. You can probably use it again but you might as well grab a new one if you can. Also torque to 7 ft-lbs.

Appreciate the info. I read some posts where people said to go with blue Loctite on the fastner. Sounds reasonable.

[kayger12]

Nice easy switch out. Not real confident that was it, though. The o-ring that I took off seemed to be in ok shape.
Shot of the CPS sensor removed:


All cleaned up and re-installed:


We'll see how she looks in a week.

Also-- part# for the o-ring if anyone needs it in the future:

[MrMaico]

Sure looks like that's where it's coming from. Is it possible it's the sender itself leaking? Although, it's not unusual for an o ring to be causing problems even though they look fine. Happens quite often at work. There is a hydraulic repair business that I go to when we need an o ring that we don't carry and he's never failed to have the right one on hand.

[kayger12]

Sure looks like that's where it's coming from. Is it possible it's the sender itself leaking? Although, it's not unusual for an o ring to be causing problems even though they look fine. Happens quite often at work. There is a hydraulic repair business that I go to when we need an o ring that we don't carry and he's never failed to have the right one on hand.

There was no oil inside of the connector, so I think the sensor was ok. Certainly possible, though.

I'll report back later this week.

Good to know about the o-ring. This is the vanos that got replaced under cpo, so I'm wondering if they just reused the o-ring or if it didn't seat properly.

Sent with Droid Fighter envy

[nike001]

Was this the same thing that you recommended might be my problem?