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 > 5 Series > E39 (1997 - 2003)

E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 02-10-2011, 09:45 AM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
E39 540i low compression

Hi guys,

I'm in the middle of what I thought it would be a valve cover gasket replacement and a few other relatively simple maintenance jobs, but the deeper I go the worse it becomes. First I noticed leaks from the head gaskets (yet to be confirmed). Yesterday I measured cylinder compression and it turned out evenly low in all cylinders at about 130psi as opposed to 170-203psi per spec (I've seen a post from one guy who measured his to be at 205 in average!). It was late at night and I didn't get a chance to do a wet test. I left the battery charge overnight just in case and will retest it again today followed by the wet test.

I read that if the wet test significantly and evenly improves compression it means worn piston rings, is that true in most cases?

My car is 1998, but only has 80k miles on it, is it a bit early for the piston rings to go? In the time that I owned it (a little over a year) I added roughly 10k miles on it and it never overheated.

Unless I'm missing it, I don't see a procedure for piston ring replacement in Bentley (if it comes to it). I haven't checked TIS yet, not sure if it has it. Where can I find the procedure explained in detail?

Any thoughts or suggestions are always greatly appreciated!

Here's a video of one of the cylinder tests, does it sound normal?



Thank you, guys, for any input!
Reply With Quote
Advertisement
  #2  
Old 02-10-2011, 09:48 AM
540indiana's Avatar
540indiana 540indiana is offline
Officially Welcomed to the 'Fest
Location: Beech Grove Indiana
 
Join Date: Oct 2010
Posts: 1,722
Mein Auto: 2000 540i Sport
Was there low compression before the replacement? I am not the strongest on engines but perhaps the vanos ???
__________________
Reply With Quote
  #3  
Old 02-10-2011, 09:50 AM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Quote:
Originally Posted by 540indiana View Post
Was there low compression before the replacement? I am not the strongest on engines but perhaps the vanos ???
Nothing has been replaced yet and this is a pre-VANOS M62 engine.
Reply With Quote
  #4  
Old 02-10-2011, 09:55 AM
540indiana's Avatar
540indiana 540indiana is offline
Officially Welcomed to the 'Fest
Location: Beech Grove Indiana
 
Join Date: Oct 2010
Posts: 1,722
Mein Auto: 2000 540i Sport
I am sure one of the gurus will chime in soon. I am about to change CCV, head gaskets,intake gaskets and anythings else that I am comfortable getting my hand dirty on.
__________________
Reply With Quote
  #5  
Old 02-10-2011, 10:04 AM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Good luck with yours

That was my plan too until I started discovering all these issues.
Reply With Quote
  #6  
Old 02-10-2011, 11:41 PM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
I did the dry and wet tests today with the following results:

1. 135 (142 wet)
2. 135 (142 wet)
3. 135
4. 135 (142 wet)
5. 140
6. 125
7. 130
8. 135

Since the change was not dramatic, this points to the valve leakage, correct? If that's true, why would they start leaking and is it possible that they are all leaking almost the same?

Regarding the information that's missing from Bentley, I've found that it all covered in TIS.
Reply With Quote
  #7  
Old 02-11-2011, 07:52 AM
franka franka is offline
Officially Welcomed to the 'Fest
Location: Lakewood
 
Join Date: Jan 2006
Posts: 8,771
Mein Auto: E39 540i Sport
Just skimming the posts above try some Techron in the gas tank. It does work and part of what it does is clean the valves of carbon allowing them to seat properly.
__________________
Frank
540/6

Dirrezas (4) @ 275/35-18, Eibach springs & bars, Bilstein Sports, Dinan Stage 2, slotted ATEs, Hi-Temp HTP pads, SS Lines, UUC-SS, White/Tan, Bling-free & Stealthy
Reply With Quote
  #8  
Old 02-11-2011, 07:53 AM
franka franka is offline
Officially Welcomed to the 'Fest
Location: Lakewood
 
Join Date: Jan 2006
Posts: 8,771
Mein Auto: E39 540i Sport
How many miles on the car and how many owners?
__________________
Frank
540/6

Dirrezas (4) @ 275/35-18, Eibach springs & bars, Bilstein Sports, Dinan Stage 2, slotted ATEs, Hi-Temp HTP pads, SS Lines, UUC-SS, White/Tan, Bling-free & Stealthy
Reply With Quote
  #9  
Old 02-11-2011, 09:05 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,234
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by 540alex View Post
why would they start leaking and is it possible that they are all leaking almost the same
Those numbers don't look too badly off. I don't know what percentage is considered abnormal - maybe someone has a spec for what the percentage off between cylinders for the BMW so you can judge against the spec?

As for what could cause loss of compression ... just one idea is a DISA valve ... which there are a few threads on ... where parts get sucked into the intake manifold, and from there into the cylinders where they are destroyed and sucked out the exhaust manifold.

There are pictures here:
- Example of how a DISA valve can ruin your engine compression (1)

But, I would think there is a well-defined test sequence for what causes the loss of compression below spec (I don't have it though ... so if/when you find it, send it my way and I'll add it to the best links thread for others to benefit from).


Last edited by bluebee; 02-11-2011 at 09:06 AM.
Reply With Quote
  #10  
Old 02-11-2011, 09:24 AM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Quote:
Originally Posted by franka View Post
Just skimming the posts above try some Techron in the gas tank. It does work and part of what it does is clean the valves o f carbon allowing them to seat properly.
Thanks for the suggestion, but I'm taking the top apart for gasket replacement already, and I think I should pull the heads too and then deal with whatever I find.

Quote:
Originally Posted by franka View Post
How many miles on the car and how many owners?
I am the third owner, bought the car almost year and a half ago with 69k miles and now it has about 80k.

Quote:
Originally Posted by bluebee View Post
Those numbers don't look too badly off. I don't know what percentage is considered abnormal - maybe someone has a spec for what the percentage off between cylinders for the BMW so you can judge against the spec?
Bentley says it should be in 174-203 range and I've seen several posts now with numbers roughly around 205, some even higher, so while my numbers may not be horrible, I think they are definitely low.

Quote:
Originally Posted by bluebee View Post
But, I would think there is a well-defined test sequence for what causes the loss of compression below spec (I don't have it though ... so if/when you find it, send it my way and I'll add it to the best links thread for others to benefit from).
It's all in Bentley. It suggests that if the wet test does not improve compression significantly, the leaky valves are the likely cause.

One last thing I want to do before I take the heads off is to verify my gauge, it's brand new, but you never know, somehow I feel suspicious of it.
Reply With Quote
  #11  
Old 02-11-2011, 09:36 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,234
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by 540alex View Post
Bentley says it should be in 174-203 range and I've seen several posts now with numbers roughly around 205
Thanks for the astute update. Much appreciated.

I see yours are universally much lower than those numbers.

I was mostly looking at the difference between cylinders ... I see now why you're looking for the general cause.

Thanks for the great response.
Reply With Quote
  #12  
Old 02-11-2011, 10:30 AM
first540i's Avatar
first540i first540i is offline
my first bmw
Location: SGV, CA
 
Join Date: Jan 2011
Posts: 338
Mein Auto: e39
maybe your timing is off a little? maybe it jumped a gear?

ima do this for my 540 once i am done installing the timing chain.. keeping my fingers crossed.
Reply With Quote
  #13  
Old 02-11-2011, 10:36 AM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Quote:
Originally Posted by first540i View Post
maybe your timing is off a little? maybe it jumped a gear?

ima do this for my 540 once i am done installing the timing chain.. keeping my fingers crossed.
Hmmm... I'll look into it, thanks!
Reply With Quote
  #14  
Old 02-11-2011, 10:41 AM
edjack edjack is offline
Officially Welcomed to the 'Fest
Location: San Jose, CA
 
Join Date: May 2007
Posts: 9,201
Mein Auto: '97 540i 6 speed
Wait a minute, folks! Let's verify the accuracy of the gauge before tearing into the engine!!!
__________________


Ed in San Jose '97 540i 6 speed aspensilber over aubergine leather. Build date 3/97. Golden Gate Chapter BMW CCA Nr 62319.
Reply With Quote
  #15  
Old 02-11-2011, 10:48 AM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Quote:
Originally Posted by edjack View Post
Wait a minute, folks! Let's verify the accuracy of the gauge before tearing into the engine!!!
Exactly! Do you know of an easy way to verify it except for buying another one?
Reply With Quote
  #16  
Old 02-11-2011, 10:49 AM
first540i's Avatar
first540i first540i is offline
my first bmw
Location: SGV, CA
 
Join Date: Jan 2011
Posts: 338
Mein Auto: e39
^ +1
Reply With Quote
  #17  
Old 02-11-2011, 12:28 PM
franka franka is offline
Officially Welcomed to the 'Fest
Location: Lakewood
 
Join Date: Jan 2006
Posts: 8,771
Mein Auto: E39 540i Sport
^ +2
__________________
Frank
540/6

Dirrezas (4) @ 275/35-18, Eibach springs & bars, Bilstein Sports, Dinan Stage 2, slotted ATEs, Hi-Temp HTP pads, SS Lines, UUC-SS, White/Tan, Bling-free & Stealthy
Reply With Quote
  #18  
Old 02-11-2011, 12:50 PM
edjack edjack is offline
Officially Welcomed to the 'Fest
Location: San Jose, CA
 
Join Date: May 2007
Posts: 9,201
Mein Auto: '97 540i 6 speed
You need to find a known accurate gauge. Auto repair shop may accomodate you.

When I want to check a pressure gauge, I compare it to several I have in my tool chest. These all measure very close to the same value, so I assume that they are statistically accurate enough to identify a bad gauge.

Let me know if you want to drive down to San Jose, and we can examine your gauge. Or, buy a general-purpose pressure gauge from Harbor Freight, and compare.
__________________


Ed in San Jose '97 540i 6 speed aspensilber over aubergine leather. Build date 3/97. Golden Gate Chapter BMW CCA Nr 62319.

Last edited by edjack; 02-11-2011 at 12:52 PM.
Reply With Quote
  #19  
Old 02-11-2011, 01:24 PM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
I just got back from AutoZone, got a gauge, will try it tonight and update.
Reply With Quote
  #20  
Old 02-11-2011, 09:23 PM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Unfortunately the other gauge confirmed the low numbers, so I'm going to continue with the disassembly tomorrow.
Reply With Quote
  #21  
Old 02-11-2011, 10:31 PM
Mercutio2511 Mercutio2511 is offline
Registered User
Location: new york
 
Join Date: Mar 2009
Posts: 56
Mein Auto: 528I
what process are u using to check the compression ratio of ur engine?
Umm OP i always open the throttle all the way when im checking for compression ratio..and the engine temperature is a factor...and the oil...and i always disable the fuel injection system too..
__________________
_JMA

Reply With Quote
  #22  
Old 02-11-2011, 10:48 PM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Quote:
Originally Posted by Mercutio2511 View Post
what process are u using to check the compression ratio of ur engine?
Umm OP i always open the throttle all the way when im checking for compression ratio..and the engine temperature is a factor...and the oil...and i always disable the fuel injection system too..
That's what I do too:

- Let the engine run until the operating temperature is reached;
- Remove DME relay;
- Remove all ignition coils/spark plugs;
- Attach the gauge;
- Crank the engine 6 times with the throttle open all the way;

Wet test is done the same way except a teaspoon of oil is added to the cylinder before the gauge is screwed in.
Reply With Quote
  #23  
Old 02-11-2011, 11:41 PM
pangolin pangolin is offline
Officially Welcomed to the 'Fest
Location: Lynnwood WA
 
Join Date: Nov 2009
Posts: 157
Mein Auto: 540i 6-speed
I have always cranked until the needle stops rising.
Reply With Quote
  #24  
Old 02-12-2011, 12:51 AM
Quackers's Avatar
Quackers Quackers is offline
Learning all the time
Location: Manchester, UK
 
Join Date: Jul 2007
Posts: 545
Mein Auto: 540i
Quote:
Originally Posted by pangolin View Post
I have always cranked until the needle stops rising.
Me too, definitely more than 6 cranks!
What kind of fitting is used? Is it threaded? Does it seal well?

Also, has the car only been used on very short journeys? 80k is no mileage for worn piston rings, but premature wear can be caused by constant cold starts and cold running.
If the car is consistently used on very light throttle settings the top end can coke up quite badly (carbon deposits) which can affect valve seating. Maybe that's a possibility, but a long shot,perhaps.
__________________
I maybe paranoid but that doesn't mean they're not after me!


Last edited by Quackers; 02-12-2011 at 01:06 AM.
Reply With Quote
  #25  
Old 02-12-2011, 11:11 PM
Flug540's Avatar
Flug540 Flug540 is online now
Officially Welcomed to the 'Fest
Location: Hayward, CA
 
Join Date: Nov 2009
Posts: 546
Mein Auto: 1998 BMW 540i 6-spd
Quote:
Originally Posted by Quackers View Post
Me too, definitely more than 6 cranks!
What kind of fitting is used? Is it threaded? Does it seal well?

Also, has the car only been used on very short journeys? 80k is no mileage for worn piston rings, but premature wear can be caused by constant cold starts and cold running.
If the car is consistently used on very light throttle settings the top end can coke up quite badly (carbon deposits) which can affect valve seating. Maybe that's a possibility, but a long shot,perhaps.
Bentley says that the pressure should reach its maximum within 4-6 stokes, which in my case proved to be true. Today I went for a drive and did the compression test again. This time I did over ten strokes, but I noticed that the maximum was reached after 4th or 5th stroke. The fitting is threaded and seals well as far as I can tell.

In the period that I own the car, it is mostly used to commute 2-3 times per week 30 miles one way of spirited driving I always give it a chance to warm up. The owner before me was a lady who used it for short shopping trips and to drive her kids to school.

I disassembled the top of the engine today, here is a video of what the intake looks like:



I think this sludge build up can affect the function of the valves. Any thoughts?

Last edited by Flug540; 02-13-2011 at 07:42 AM.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)
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 09:08 PM.


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