A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto makers » BMW
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

M52 high oil consumption



 
 
Thread Tools Display Modes
  #11  
Old September 25th 15, 02:18 PM posted to alt.autos.bmw
wektor
external usenet poster
 
Posts: 1
Default M52 high oil consumption

replying to John Burns, wektor wrote:
M 52 has one main problem
he DISA valve, otherwise known as the «Intake Manifold Adjuster Unit», is
located on the side of the intake manifold and is a common failure on the M54
and M52TU BMW engines. The failure is caused by the type of materials used in
the manufacture of two of the three key valve components. The three key
components of the DISA are the flat plastic flapper valve which opens and
closes depending on engine rpm and throttle position, the bell crank lever
that rotates it, and the vacuum pot that actuates the bell crank lever. The
flapper valve is made of 30% glass reinforced nylon and the bell crank lever
is made of standard 6/6 nylon. As shown in the pictures on the left, the bell
crank lever has a male, hex shaped protrusion, which snaps into a matching
female pocket on the flapper valve. These hex shaped sections are what allow
the rotation of the bell crank lever to rotate the flapper valve.

During normal engine operation, vibrations from pressure pulses inside the
intake manifold cause the bell crank lever and flapper valve to vibrate
against each other where the hex shaped portions contact each other. These
vibrations start a wear process which will cause the tiny glass fibers in the
flapper valve to become exposed. Once the fibers become exposed they start to
erode away the male hex portion of the weaker bell crank lever. As soon as the
erosion starts it’s all down hill from there until the hex is completely
worn away. The symptoms of a worn DISA valve include rough idle, lean engine
codes and lack of low to mid rpm power.
If you disassemble a worn out DISA valve and look at the bell crank lever
it’s common to not even recognize that it once had a hex shape on the
protrusion. Once the hex is shape is worn off the lever, the flapper valve no
longer opens and closes in a controlled manner by the rotation of the bell
crank lever. The brittle flapper valvebecomes free to slap around uncontrolled
within the DISA support framework. This uncontrolled movement can lead to
complete destruction of the flapper valve. The broken pieces of valve have no
where else to go except through the intake manifold runners and through the
motor, sometimes resulting in severe engine damage. Even a small piece of
plastic broken off the flapper valve can hold an intake valve open, resulting
in bent valves or much worse.

Since the only parts on the DISA valve that typically fail are the flapper
valve, bell crank lever and housing seal, why replace the entire unit. Replace
the failed internal parts with these http://vanos-bmw.com/disa-bmw-repair-kits
upgraded parts and have a much more reliable DISA for 1/3 the cost.

--
posted from
http://www.motorsforum.com/bmw/m52-h...ion-29935-.htm
using MotorsForum's Web, Mobile and Social Media Interface to
alt.autos.bmw and other automotive groups

Ads
 




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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fix for high oil consumption - New Spark plug, new valve stem onnumber 5 and seal Mick x Audi 14 July 21st 07 01:15 PM
High fuel consumption with A6 Mark Audi 4 July 7th 05 09:08 AM
Syn Oil Consumption Randall Brink VW air cooled 8 April 16th 05 01:24 PM
High fuel consumption and cracked exhaust manifold? Jason Honda 4 February 18th 05 03:53 AM
High Fuel Consumption since I fixed the heat sensor Jason Honda 4 November 30th 04 01:57 PM


All times are GMT +1. The time now is 06:27 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.