VANOS Problems

[macfly]

There seems to have been several reports of problems with the S62 motor's VANOS Sytem, and it's hydraulics, here is the latest info from BMW on the fixes.

This is covered in SIB#110401 and applies to M5 and Z8 cars produced up to
11-30-00

A rattling noise coming from the front of the engine area may be heard for a
few seconds after startup. When the engine is shut off oil bleeds out of the
Vanos. This has no effect on engine power output or durability.

Correction - A Vanos accumulator shutoff valve can be installed to eliminate
the momentary rattling noise.

Kit part #'s

11-36-7-832-856 - for Z8's produced up to 9-1-00

11-36-7-832-858 - for Z8's produced 9-1-00 to 11-30-00

This is not a recall or campaign and is performed on a customer complaint
basis only.

I also have two PDF documents from rvacha over on BMWM5.COM that I can email to anyone who needs them. Sadly this software won't allow me to post them here.

One of the documents describes the problem, and the easy fix, and the other the more complex complete removal and rebuild of the system. They are taken from the BMW Tech CD.

Also I started a poll over there to see how the reliability of the S62 was for the many M5 board users, as it is the same unit.

http://www.bmwm5.com/vbulletin/showthread.php?s=&postid=235267


Board member Lupo has had these additional Vanos fixes performed to his car.

The VANOS accumulator shutoff had been done previously. The fix
being done now is for the constant VANOS rattle even while the engine is
running hot. Apparently there is no service action number for this spring
and washer fix. My tech writes:

"...basically its info from the manufacturer not meant for release
but available to BMW technical rep's on a secured database
code named HUS. If the others are having difficulty getting
action from thier dealers they should contact their area BMW rep and he
can access the info."

[macfly]

VANOS stands for VAriable NOckenwellen Steuerung (variable cam control) and is BMW's nomenclature for a system to adjust valve timing to optimize an engine's performance under varying conditions.

There is a VANOS system to control intake valve timing and another VANOS system to control exhaust valve timing. When both are used on an engine, the system is called DOUBLE VANOS. The Z8's engine incorporates DOUBLE VANOS.

The following explanation is over-simplified but hopefully adequate for discussion purposes. The purpose of the intake system on an engine is to combine air with fuel and deliver the mixture to the cylinders where it can be compressed, ignited by a spark to create power, then sent to the exhaust system for elimination. In order for the air/fuel mixture to enter and leave the cylinders, it must pass through openings in the cylinder heads. These openings have valves in them to control whether they are open or closed. Whether the valves are open or closed is determined by the camshafts which have lobes on them to force the valves into the open position, while springs force the valves to close.

The important thing to understand is that on most engines (without VANOS) the rotation of the camshafts, thus the timing of the openings and closings, is fixed in relationship to the rotation of the crankshaft and therefore the positions of the pistons in the cylinders. The trouble with a fixed relationship is that as the engine runs at different speeds, the optimum timing of the delivery of the air/fuel mixture and its subsequent release into the exhaust system varies. This means that a fixed valve timing system can only deliver optimum conditions for combustion at one specific rpm; every other rpm will be a compromise.

Enter DOUBLE VANOS! By developing a way to vary the relationship of the camshafts' rotation to the crankshaft's rotation, BMW can optimise the timing of the delivery of the fuel/air mixture and its release into the exhaust system. This is accomplished by a moveable camshaft drive gear with a helical timing gear. As the camshaft drive gear moves in or out, the helical cut of the timing gear forces the camshaft gear to rotate forward or backward slightly. This changes the timing of the camshafts' rotation relative to the fixed rotation of the crankshaft, thus allowing the valve timing to be advanced or retarded. The onboard engine computer is put in charge of deciding what that timing should be to optimise engine performance and it uses hydraulics to move the shaft in or out. The Z8's DOUBLE VANOS system can adjust the intake valve timing by 54 degrees while the exhaust timing can be adjusted by 39 degrees. The adjustments take less than 250 milliseconds.

The benefits of having DOUBLE VANOS on the Z8 include high torque at low and medium speeds, reduced emissions, better fuel consumption and smoother idling. When combined with the Z8 engine's individually controlled throttle butterflys, engine performance can be controlled to an unprecedented degree, resulting in what many consider to be the finest production engine BMW has ever built.

Grease Monkey

[macfly]

S62 VANOS Update

Having now done both the VANOS upgrades that were recommended by my BMW master tech, and having driven the car for a few days, under different temps and conditions, I can highly recommend to those who suffer from the annoying "rattle" noise that these two VANOS updates work. I would say that 80% of the noise has disappeared, which is deemed normal. I can actually here my engine now, and relish in the low rumble of my Eisenmann exhausts at idle. I had a chance to listen to a 2003 M5 that was at the dealer when I picked up my car and the "rattle" was evident. A tad quieter, but noticeable. So it's all normal, folks.

The two VANOS updates as we have discussed in previous posts:
1) Accumulator shutoff -SIB#110401
2) Stiffer spring and thicker washer for the VANOS disk. This doesn't have a service number. My tech explains: "...Basically its info from the manufacturer not meant for release but available to BMW technical rep's on a secured database code named HUS. If the others are having difficulty getting action from their dealers they should contact their area BMW rep and he can access the info."

For those who haven’t seen them, here are some photos my tech sent me while applying the spring and washer update:

[Lupo]

I thought I'd quickly post part numbers for those who wish to have this done. This is all covered by warranty folks, so if you haven't had it done, I highly recommend it.

Replace Updated VANOS Springs: Defect code # 00 12 42 01 00

QTY:
2 Gasket- 11-36-1-406-838
4 O-Ring 85x2mm- 11-36-1-406-868
4 Ring- 07-11-9-963-072
2 Diaph.Spring- 11-36-7-833-218
2 CirClip- 07-11-9-934-749
1 Gasket-11-12-0-001-269
1 Gasket-11-12-0-001-278
2 Gasket-11-14-0-001-186
40 Antifreeze- 83-51-9-415-964

:D Cheers

[siliconvalleyman]

I was wondering if this was fixed in the '2002 Model year.

[macfly]

Even on the earlier cars it seems that only about 20% of them had any problems with this issue anyway. My July '00 build never gave any signs of the problem, and I did over 17,000 hard driving miles in it, including around 3,000 track miles.