5 Series E34 525td (M51) TOUR
VK-23/Sasse
Baugruppe/Group: 11
11 03 94 (795)
weltweit
all countries
05/1994
Version: 01/96
Checking cylinder head
M41, M51
Situation:
As service life increases, cracks form in the combustion and web area which, up to a
certain point, do not have any adverse effect on operation. This is due to tension reduction
and was taken into consideration during the design phase.
These cracks have led dealer personnel to assume that parts are faulty. However, a large
proportion of returned cylinder heads were found to be in good working order by the
warranty parts-testing department.
So that cylinder heads are not replaced unnecessarily, variations permitted between the
new part and the older part are described in the following.
Procedure:
1.
Note when removing/installing:
The cylinder head must be unscrewed when the engine is cold as otherwise the
cylinder head will become distorted.
Renew all cylinder head bolts whenever the cylinder head is removed.
2.
Measuring deflection with straight-edge:
In the combustion chamber area of each cylinder (shaded in illustration) the surface
may be very slightly uneven. Measurements using a straight-edge on these surfaces
(e.g. "diagonal measurement") may be inaccurate. This method is therefore no longer
permissible.
The measurement should be carried out according to the lines marked in the
illustration.
Maximum deflection lengthways: 0.10 mm, across: 0.05 mm
SI Checking cylinder head M41 M51
BMW AG - TIS
23.01.2013 05:51
Issue status (12/2007) Valid only until next DVD is issued
Copyright
Page - 1 -
