Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E46 (1999 - 2006)

E46 (1999 - 2006)
The fourth generation 3 Series (E46 chassis) was introduced in 1999 and set the standard for engineering and performance during it's years of production including being named to Car & Driver's 10 best list every one of those years! ! -- View the E46 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 05-28-2012, 06:14 AM
samm1978 samm1978 is offline
Registered User
Location: London
 
Join Date: May 2012
Posts: 10
Mein Auto: BMW 318i E46
Question BMW recurrent oil leaks - piston rings or something less sinister?

Hi All

Apologies for joining and jumping straight into a question but I was hoping you could help me.

My BMW 318i 2002 e46 has done 103000 miles and otherwise drives nicely but has had oil leaks almost consistently for the past two years. At first it was the rocker cover gasket, then it was two rings accross the front of the engine, then it was the sump gasket and now its the rocker cover gasket again.

I recently took it to a garage I haven't used before who said it was due to the piston rings going. They said that would explain why I keep getting leaks and also took off the oil cap and there was some pressure coming out as a little oil was spitting up. I was quite surprised as I haven't otherwise felt anything wrong with the car or a drop in performance but they didn't feel the need to diagnose any further?

Is there anything less sinister and a little easier to fix that it could be? I just cant afford to replace the engine or have it overhauled.

Any help/advice would be greatly appreciated.
Reply With Quote
Advertisement
  #2  
Old 05-28-2012, 06:47 AM
bmwtech78 bmwtech78 is offline
Registered User
Location: Atlanta
 
Join Date: Jan 2012
Posts: 37
Mein Auto: anything not german
Run away fast, they have no idea what they are talking about. When removing the oil cap you should have suction if you have pressure I would assume the crank case vent valve is bad. A bad ccv valve can cause oil leaks, The positive pressure can push oil past the seals. However leaking valve cover gaskets are very common and it may just be time for another one. How long ago was it replaced?

Sent from my R800x using Bimmer App
Reply With Quote
  #3  
Old 05-29-2012, 06:02 AM
samm1978 samm1978 is offline
Registered User
Location: London
 
Join Date: May 2012
Posts: 10
Mein Auto: BMW 318i E46
BMW recurrent oil leaks - piston rings or something less sinister?

Is the valve cover gasket also known as the rocker cover gasket? If it is it was replaced less than 3 months ago and is already leaking. It seems one seal after the other is going.

The mechanic said something about if the breather was the problem then it would be hard to take the oil cap off and you would hear a sucking noise when you did take it off - because its easy to take mine off and there appears to be pressure in there and not a vaccuum he concluded the pistons have gone.

Just cant afford an engine rebuild but wanted to do more research before I think about getting rid
Reply With Quote
  #4  
Old 05-29-2012, 08:39 AM
cvx5832 cvx5832 is offline
Officially Welcomed to the 'Fest
Location: Walnut Creek, CA
 
Join Date: Jan 2009
Posts: 503
Mein Auto: 325Ci, 325Cic, C300
Yes it's the same thing. A bad CCV can trash an otherwise healthy valve cover gasket because of incorrect (excess) pressure.

That mechanic may not necessarily be familiar with BMW CCVs. I've seen them fail both ways, either like yours with excess positive pressure (clogged) or with excess negative pressure accompanied by goose sounds indicative of a torn diaphragm.

I'd go somewhere else. If the replacement process is anything like the M54, I'd just change it myself.


Quote:
Originally Posted by samm1978 View Post
Is the valve cover gasket also known as the rocker cover gasket? If it is it was replaced less than 3 months ago and is already leaking. It seems one seal after the other is going.

The mechanic said something about if the breather was the problem then it would be hard to take the oil cap off and you would hear a sucking noise when you did take it off - because its easy to take mine off and there appears to be pressure in there and not a vaccuum he concluded the pistons have gone.

Just cant afford an engine rebuild but wanted to do more research before I think about getting rid
Reply With Quote
  #5  
Old 05-29-2012, 10:01 AM
rgk330i's Avatar
rgk330i rgk330i is offline
Officially Welcomed to the 'Fest
Location: Fairfax, VA
 
Join Date: May 2002
Posts: 247
Mein Auto: 2013 335i M-Sport
Seems irresponsible -- or worse -- to talk about piston rings without even doing a compression or leak-down test. Bad rings are uncommon, a bad CCV valve is very, very common. I wouldn't break into a panic just yet.

On the M54 engine, the CCV replacement is not especially difficult but it is a bit involved since the CCV is pretty well hidden under the intake manifold. I have no idea about the N42.
__________________
2013 335i M-Sport, ED May 2013
Reply With Quote
  #6  
Old 05-29-2012, 03:20 PM
samm1978 samm1978 is offline
Registered User
Location: London
 
Join Date: May 2012
Posts: 10
Mein Auto: BMW 318i E46
BMW recurrent oil leaks - piston rings or something less sinister?

Thanks guys - you've given me some hope I love my car, even with what my daughters done to the interior (baby food and oranges)

I took it for a 50mile round trip and it drove beautifully. I also kept an eye out in the mirror to see if I was letting any big puffs of blue smoke or anything out the exhaust and didn't notice anything. In fact if it weren't for the oil leak I wouldn't think anything was wrong with the car at all.

Just wondering - before the rocker cover gasket the cam gaskets were leaking and before that some other seals at the front and before that the rocker cover gasket again. Would a blocked CCV only affect the rocker cover gasket or could it affect the other seals as well?

I think I'm going to have a go at getting to the CCV to see the state of it. Is it something that can be done from the top or would I have to get under?
Reply With Quote
  #7  
Old 05-29-2012, 03:30 PM
cvx5832 cvx5832 is offline
Officially Welcomed to the 'Fest
Location: Walnut Creek, CA
 
Join Date: Jan 2009
Posts: 503
Mein Auto: 325Ci, 325Cic, C300
Quote:
Originally Posted by samm1978 View Post
Just wondering - before the rocker cover gasket the cam gaskets were leaking and before that some other seals at the front and before that the rocker cover gasket again. Would a blocked CCV only affect the rocker cover gasket or could it affect the other seals as well?
A blocked CCV would affect all seals exposed to that excess positive pressure.

Most here will not be familiar with your particular motor setup as we mostly have 6-cylinder M52s and M54s. Google it though as you might get lucky. I'd pick up a repair manual too if you intend on keeping the car a while longer.

CCV repairs are not expensive parts-wise so it pays off to do it yourself. Not sure what a definitive diagnostic method would be if you did get it out of the car, but at that mileage I would replace it anyway.
Reply With Quote
  #8  
Old 06-01-2012, 07:33 AM
Fifty_Cent's Avatar
Fifty_Cent Fifty_Cent is offline
Pure Natural BMW Muscle!
Location: Nicosia, Cyprus
 
Join Date: Sep 2003
Posts: 1,574
Mein Auto: 320CiC
N42s early valvetronics are famous for their oil leaks...

have a look here:
http://www.bimmerforums.co.uk/forum/...ngine-t106504/
and here:
http://www.bimmerforums.co.uk/forum/...repair-t89903/
__________________

Last edited by Fifty_Cent; 06-01-2012 at 07:36 AM.
Reply With Quote
  #9  
Old 02-12-2014, 04:49 PM
samm1978 samm1978 is offline
Registered User
Location: London
 
Join Date: May 2012
Posts: 10
Mein Auto: BMW 318i E46
Hi - just wanted to thank everyone who helped me in this post - glad to say I had the CCV changed and yes it was blocked through and through. Glad I didn't listen to the mechanic who told me it was the piston rings but still wanted to charge me 400 to replace the rocker cover gasket...

I guess there's a lesson there for other owners - if you keep getting oil leaks in your car from one gasket after another - replace the CCV
Reply With Quote
Reply

Bookmarks

Tags
breather valve, ccv, crank case ventilation, gasket, oil leak, piston rings


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E46 (1999 - 2006)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 05:07 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms