6-cyl double vanos problem assessment

[chivas]

from the factory and why can't it be replicated.

[assjack318]

TR
BMWCCA

1995 318i * Artic Gray Metallic * H&R Sport/Bilstein Sport * BMP shock mounts * Powerflex Offset CABs, RTABs, & subframe Bushings * 17" M5 Replicas * Khumo Ecsta Supra 712 * K&N Conical Filter * Remus Exhaust * Front Lip Spoiler * 3.45 LSD * Zimmerman X-drilled Rotors F/R * S/S Brake lines F/R * M3 Front Swaybar Endlinks

[cn]

Hi,

I have been reading the Vanos problems. I have a few questions: hope the experts can help:

According to:
http://www.everything2.com/index.pl?node_id=968280
-------------
BMW Engine Types* which incorporate VANOS:

M50TU: Inline 6 cyl. engine, single VANOS.
M52: Inline 6 cyl. engine, single VANOS.
M52TU: inline 6 cyl. engine, double VANOS.
M54: Inline 6 cyl. engine, double VANOS.
M62: V-8 cyl. engine, single VANOS after 1998 model year.
M73: V-12 cyl. engine, single VANOS after 1998 model year.
S50: Inline 6 cyl. engine, single VANOS.
S52: Inline 6 cyl. engine, double VANOS.
S54: inline 6 cyl. engine, double VANOS.
S62: V-8 cyl. engine, double VANOS.
------------

QUESTIONS:

1. Is mine "M52: Inline 6 cyl. engine, single VANOS"

2. Is my engine affected by this Vanos problem? It seems that "Double Vanos" gets more problems than "Single Vanos", is this true?

3. If the Vanos problem ever happens (hope not), How long is the fix (removing the vanos and change the seal)....I am mechanically inclined but not looking for doing this type of work at all! Just curious how many hoyurs involved if it ever happens to my engine.

4. Where to buy the seals?


TIA
cn
1998 528i 5spd 87K

[loach1]

I removed one by hand with little/no damage and stretched it only very slightly. I believe they either put them on by hand or install them as much as possible without stretching, then compress the ring portion that is in the groove (squashing the supporting o-ring), making it easy for the teflon seal to fall into the groove.

[AprilGoose]

have double VANOS and are prone to the issue. It is not something you would want to try fixing yourself unless you are pretty handy.

[cn]

http://bimmer.roadfly.com/bmw/forums/e39/7494985-1.html

cn
1998 528i

[eBlue540]

First: EXCELLENT research by both you guys!

You have presented a really excellent report on this. I am curious about your thoughts on one aspect of the cold engine Vanos function:

Given that at cold start, oil is relatively more viscous and oil pressure will be relatively higher than when fully warmed, what mechanism is "restoring" Vanos function once engine is fully warm? Given that the seal problem would seem to result in excessive bypass of oil against the spring of the exhaust side vanos, what "improves" the seal of the hot engine vanos? OR do you believe the failure mechanism to be a seal "sticking" problem instead of an oil bypass issue?

I apologize if I somehow missed this in you post or in one of the many response to this post - I have not looked at them all. Just looking to better understand the issue.

Good luck with getting BMWNA to respond!

ChrisS.E. Pennsylvania
'98 540/6 Estoril Blue
BMW M-sport grnd effects and trim painted to match, B&B Exhaust, Dinan CAI w/stage II SW, UUC S-Shifter, CDV delete
'03 Passat GLX Wagon, Anthracite Blue
'93 Passat GLX Wagon 5-spd (Station Car)

[Rico24il]

[Rico24il]

I just took my E39 528i year 2000 to the dealer today with the VANOS problem. I printed the whole thread posted by Loach & Rajaie and handed it to the service advisor. They kept the car the whole day and called me in the afternoon saying that the car needs to be kept overnight so they can start it cold tommorow. They said they have procedures and tests for checking the VANOS. The car is still under the CPO. I will keep you all posted and as soon as I know something, I will write it on the board.

[bobsut]

Should M3 and M Roadster/Coupe owners worry too?

Would it affect Euro S50B30 and S50B32 with their much earlier double VANOS?

[tlcoll5866]

Just one more reason to keep old BMW,s. Great story my 99 528is does
this all the time until warm. So I guess I shouldn't worry about the ICV. Thanks Tim

[Twobeemers]

I have had this problem for the past few years ('99 528i) and somebody pointed to the Vanos being the problem and someone else thought perhaps it was the Idle Control Valve. I have not attempted to address either and my car spends it's nights snuggled into a nice, warm, 45 degree garage. So I don't have it as bad as many here, but I still have it. And I've also noticed a flat spot in the acceleration somewhere north of 4k rpm. I'm assuming this is also a symptom of the car not working as it's suppose to.

The clarification I'm looking for is this - the symptom is the idle stall when warming up, but the reality of the situation is that the Vanos is not performing as it should be, not only during warmup but ALL OF THE TIME. So I'm not getting all of the benefits of double vanos at any time, not just during warmup.

I'm really hoping BMW steps up and does something about this. Or someone finds a decent fix for this problem. It sounds like replacing the Vanos unit doesn't make the problem go away permanently even if that is deemed "the fix".

John Virnig
Waukesha, WI

[16kpsi]

I spend a far amount of my time dealing with both reciprocating, rotating and recipro/rotating seals at high and medium pressure. Looking at the photos, it seems one seal is a square section seal, the other is o-ring type. If so, then I'm suprised to see an o-ring style in rotating service of this type. Generally, a form of lip seal is used for recipro/rotating service - but these are only good at relatively low pressures(and engine pressure of 60+ psi would require careful lipseal design), and require a hardened surface to run on. Even then they will eventually erode their running surface, mostly from the rotating action. Square section seals help, but they are usually energized to the seal surface by an elastimeric ring to account for wear. (see Busak-Shamban Seal company, type Roto Glyd Ring). Either way, the seal surface is usually required to be hardened to prevent scoring by the seal - other wise, the seal material would need to be soft enough to prevent surface wear - but something HAS to give. If we need to use aluminum, we will anodize and post polish the surface. This is not a cheap manufacturing process. I can't tell if the seal surfaces have been processed to increase hardness from the photo, it would seem inevitable. While the operating pressure is not extremely high, the rotational speed is to me to be in a difficult range to create a low cost, long lasting, reliable seal that is as simple as the one you have pictured.

Good luck with this guys. Good work so far.


.

Haven't we already discussed this?

[16kpsi]

they generally rely on a very concentrated line to provide the seal which will wear the mate surface over time, no matter how soft relative to the shaft or cylinder - specifically in the rotating environment. Additionally, the are non liniar in their load (higher pressure, higher load), this is probably not an issue in this design, however - plenty of HP availible to drive the shaft.

I posted below, but will reiterate a little here.

Elastomeric charge square section seals are designed specifically for this application (they are higher cost, but at BMW's volume, they wouldn't be the $15-$60 each we pay). Busak-Shamban
They are not what is picture here, for sure.

Another more essentric type of design for under 100-150psi is the ceramic face seal (John Crane type seal). These are a virtually zero wear, low friction seal that are a pressure balanced type seal. They do, unfortunately, take up a large amount of realestate and are limited in their stroke. Also not cheap in a high quality configuration.

I certainly feel that an O-ring and a non-energized square section seal are a pour choice for this application, but I would prefer to have parts in hand to make any more educated comments. I don't have a dual vanos I6 vehicle, so won't have to make this unfortunate discovery myself. PITA.

.

Haven't we already discussed this?

[16kpsi]

it is a tapered cone that will mate to the piston and stretches the seal uniformly until is can clear the OD. The seal will snap down into it's groove. This can also be used in an assembly line and automated, but I would bet you are right that they do these by hand, but I'm reasonably sure they will use a guide plug - it avoids the seal hanging and point deforming on the piston edge as that last bit gets streches onto the OD.

[goldsman]

A word of caution -- before I retired I headed a national practice for one of the Big Four public accounting firms. We represented clients (individuals and companies including some of the biggest companies in the world) in matters involving the Federal Government. When dealing with the government you must always be aware of the law of unintended consequences. Getting the EPA, or a state equivalent, involved may sound like a good idea one thing to keep in mind is that while you can sometimes turn them on you can't turn them off. And you never know where a government bureaucrat will want to go with the issue.

[chivas]

[Rico24il - VANOS UPDATE]

Just to update my recent posting. Today I took my 528i 2000 back from the dealership. It was there with the VANOS bad and acting up when cold. They performed tests and procedures and agreed with it. They also put a steel gasket, put profile gasket set, a bush and a gallon drum 5W30 as I read from the invoice. The car is still under the CPO. If you have any questions, please post them.

[rajaieq]

I had mentioned it to him in phone conversations. He said that BMW would be more interested in redesigning the vanos than fixing it. He was right. The new vanoses have different designs.
He also thought that if the EPA got involved they'd make the owners replace their vanoses so they would be compliant. I didn't point out to him that the DME not throwing a code should be a violation.
Rajaie
528i 5sp 06/00

[rajaieq]

Rajaie
528i 5sp 06/00