Engine rattle - BMW Forum - BimmerWerkz.com
BMW Forum BMW Forum

» Auto Insurance

» Featured Product
» Wheel & Tire Center

Go Back   BMW Forum - BimmerWerkz.com > BMW Model Specific Forums > 5-Series (E12,E28, E34, E39, E60)
Register Home Forum Active Topics Gallery / Showroom Auto Loans Garage Search Today's Posts Mark Forums Read Auto EscrowInsurance

5-Series (E12,E28, E34, E39, E60) Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)

BimmerWerkz.com is the premier BMW Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 11-20-2005, 11:03 AM   #1 (permalink)
n00b
 
Join Date: Nov 2003
Location: Bath, UK
Car:
Posts: 39
Photos:
broketiltuesday is an unknown quantity at this point
Engine rattle

Hi,

I have a 1989 (m20 engine etc) 525i. About a month ago, it started developing a loud rhythmic click/rattle noise from the engine bay. It makes this noise loudest when the throttle is open engine is under load, like going up a hill in a high gear, etc. IT doesn't seem to occur (or at least is too quiet to hear) at low throttle openings. The noise gets faster with rpm but occurs only when the throttle is open past a certain point (ie if i stamp on the gas at 1500 or 3000rpm it makes a very similar sound). The normal note of the engine is there, just with this extra rattle. Idle seems to have also developed a slight clatter. This noise sounds very much like descriptions I've read of pinking and is fairly loud - i can hear it in the cabin etc!

After a bit of investigation, it seems cylinder 5 is responsible. Disconnecting this plug at idle removes the clattering note. The idle is rock steady with/without cylinder 5 connected. A short drive with plug 5 disconnected sees the rattle completely removed. So I'm assuming that something is going wrong with the combustion process in cyl 5. The injector seems fine (impedance is 15.5ohm and i can hear it clicking normally), the ignition system is in fair shape. Engine temperature is always at the normal mark, ie. no overheating. When examined, plug 5 was in good shape if a little fouled, replacing it with a known good one had no effect.

So. Has anybody else had this problem, or can anyone give me some pointers on what else to check, and what could be causing this noise? Any ideas appreciated!

Cheers,
Tom
__________________
Gone but not forgotten: '87 UK 318... Carb madness!
Currently: '90 UK 525i completely stock

"Heaven for the climate, Hell for the company."
-Mark Twain
broketiltuesday is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 11-20-2005, 03:17 PM   #2 (permalink)
Millions of them.
 
Torque's Avatar
 
Join Date: Dec 2003
Location: USA
Car: e36 w/ a m42
Posts: 14,878
Photos:
Torque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond reputeTorque has a reputation beyond repute
Tom,

I'd start by having a compression test done to make sure that cylinder 5 is not indeed completely gone if that's what you suspect is. Other than that, only source of rattle I can possibly think of is one of the 2 valve lifters for cylinder 5 -- but then again, that wouldn't go away if you took out the cyl. 5 plug as the camshaft still hits them.

Anyway, at the top of the 5 series forum is a 'Bentley Service manual for e34'. If you don't have it, download it and look through there as it has much more information than I can come up with.

Good luck, and please post back when you figure it out, as I am very interested in this.
__________________
Torque is offline   Reply With Quote
Old 11-21-2005, 04:50 PM   #3 (permalink)
n00b
 
Join Date: Nov 2003
Location: Bath, UK
Car:
Posts: 39
Photos:
broketiltuesday is an unknown quantity at this point
Torque,

Many thanks for the reply. I'll get a compression test (a shop diagnosis as well unless I have any more ideas) when I go back home in 3-4 weeks. I don't know any good shops around here and I don't drive much atm so it can just wait.

A post on roadfly is suggesting wrist pins/rod bearings for that cylinder, ie the force under combustion is placing a force on the rods/pins that's making the rod knock against some other component on the downward stroke hence the noise. This doesn't occur when the piston is 'freeloading' when not under combustion. It sounds a little lighter than I'd associate that kind of knocking with but I can't think of much else atm (unless there's something wrong with the mixture and the fuel isn't detonating correctly, hence causing some kind of noise).

In the meantime I'm pretty puzzled but will post if anything else occurs.


Cheers,
Tom


[Edit: good job on the bentley's by the way. it's a lot better than my haynes book...]
__________________
Gone but not forgotten: '87 UK 318... Carb madness!
Currently: '90 UK 525i completely stock

"Heaven for the climate, Hell for the company."
-Mark Twain
broketiltuesday is offline   Reply With Quote
Old 11-21-2005, 06:11 PM   #4 (permalink)
5th Gear Member
 
billB's Avatar
 
Join Date: Aug 2004
Location: New Jersey
Car:
Posts: 1,635
Photos:
billB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond repute
Send a message via Yahoo to billB
Tom

When you get back home try to start the engine for 20 seconds only; listen to the sound and then Shut it down , pull the spark plug from # 5 and pour little bit of motor oil into its cylinder . Reinstall the plug, start the engine up again and listen. If you have piston slap the noise will be reduced - possibly eliminated…..BUT for a very short period of time.....Then the noise will come back.

Regards
billb
billB is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  BMW Forum - BimmerWerkz.com > BMW Model Specific Forums > 5-Series (E12,E28, E34, E39, E60)


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
'02 318 Idle / 1500rpm Engine Rattle matrhos 3-Series (E46, E90) 3 09-03-2005 09:32 AM
Bad Engine Idle And Fault Not Found.. Paraklas 3-Series (E21, E30) 10 06-16-2005 09:25 PM
BMW P83 Engine triggrhaapi Bimmer Talk/Motorsports Talk 0 07-21-2003 02:03 PM

Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 05:00 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.3.2
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.