Complaint: Rattling noises in the area of the valve timing gear with engine at operating temperature and at idle. The noises do not stop, even after a lengthy period driving.
Cause: In isolated cases, this complaint can have several different causes:
HVA element:
- Particles of dirt in the oil circuit are washed though the HVA elements and settle on the check valve. The check valve to the high pressure chamber of the HVA element does not close properly. The HVA element then becomes "soft" and can cause rattling noises.
- HVA element sticks.
- Fractured tappet as a result of hardening error.
- Traces of wear, scratches, cracks on the tappet and tappet guides.
Inlet valve, exhaust valve:
- Valve stem sticks, jams in the valve guide.
- Valve spring broken.
- Valve seat/valve plate eccentric.
- Valve guide deformed.
Oil pump (affects only engines M50 and M52):

Figure 1: Oil pump M50, M52
1) O-ring 2) Spacer sleeve 3) Control valve ne 4) Intake manifold flange

- Missing or damaged O-ring on the spacer sleeve of the control valve (see Fig. 1, item 1).
- Processing error on spacer sleeve (Fig. 1, item 2). Due to an excessively deep bore, the end face can be drilled through by the tip of the drill bit (small hole, diameter less than 1mm).
Oil pump (affects only engines M42, M50 and M52):
- Leaks between the intake manifold and the oil pump due to loose bolt connections (tightening torque: 10 Nm), damaged gasket, incorrect installation position of gasket or uneven sealing face between intake manifold flange and oil pump (Fig. 1, item 4).
All oil pump fault patterns described above lead to air ingress and oil foaming.
Affected vehicles: E30, E36/M42 Manufacturing period: from start of series production (09.89) E34, E36/M50 Manufacturing period: from start of series production (03.90) E36, E38, E39, E46/M52 Manufacturing period: from start of series production (09.94) E31, E32, E34, E38/M60 Manufacturing period: from start of series production (09.91) E31, E38, E39/M62 Manufacturing period: from start of series production (04.95) E36/S50U Manufacturing period: from start of series production (03.94) E36/S52 Manufacturing period: from start of series production (04.96)
Procedure: Check HVA elements
- Remove cylinder head cover.
- Turn the engine until the cam of the HVA element to be checked is in the base circle position (engine valve completely closed).
- Repeatedly apply a force of about 10 N (approx. 1 kg) to the HVA element by pressing with the thumb or using a folding leg (= special tool no. 00 9 321 from assembly wedge kit ne 00 9 310) or hardwood wedge. If the HVA element yields slightly as though spring-loaded, this is a sign that air is trapped in the high pressure chamber.
- Apply a force of about 20 - 30 N (approx. 2 to 3 kg) for 10 to 15 seconds to the HVA element by pressing with the thumb or using a folder/hardwood wedge. If clearance is created when the force is applied, this is a sign that the check valve in the HVA element is not closing properly, e.g. due to contamination.
- Measure the clearance between the HVA element and the cam base circle with a feeler gauge. If clearance can be detected, this indicates that the HVA element is sticking.
- Conduct the tests described above on all HVA elements. Mark any suspect HVA elements.
Further procedure if almost all 24 HVA elements are "soft":
In such cases, the HVA elements are not faulty, but rather air has penetrated into the oil circuit via the oil pump (oil foaming).
- Check the O-ring (see Fig. 1, item 1); replace if necessary - M50, M52 only.
- Check the spacer sleeve (see Fig. 1, item 2); replace if necessary - M50, M52 only.
- Check for leaks between the intake manifold and oil pump (Fig. 1, item 4); correct if necessary - M42, M50, M52 only.
Further procedure if none or only few of the 24 HVA elements were suspect:
- Remove camshafts.
- Remove bearing banks complete with HVA elements (M42, M50, M52 only).
- Remove HVA elements marked as being faulty.
- Examine all other HVA elements for traces of wear, scratches, cracks, splinters or other signs of damage (burrs, contamination).
N.B.: Used HVA elements are only to be reused in the same tappet bore.
- Check tappet bores for signs of wear (grooves).
- Check camshafts for signs of wear.
- Check valve springs for cracks.
- Replace any components which appear suspect.
- Replace all 24 HVA elements if no fault at all can be found in the above tests.
- Reassemble the engine and conduct the bleeding procedure as described in Enclosure 2.
- In exceptional cases, rattling noises may still be heard. These may be due to one of the following causes:
Inlet valves, exhaust valves:
Valve stem sticks, jams in the valve guide. Valve seat/valve plate eccentric.
Signs of this fault are poor idling quality and high HC emissions (raw HC emissions > 350 ppm).

BMW TIS - Valve timing gear rattling with engine at operating temperature and at idle Complaint: Cause: Affected vehicles: