Vanos Solenoid Replacement

[TechnoV]

Gents,

I have the standard Vanos noise that we are all aware of on my '97 M3/4 w/64K miles. I have replaced the lower chain tensioner and that reduced the noise but it is still clearly there.

Has anyone on the board gone in and replaced the Vanos solenoid inside the unit? If so, how much is it? Part #?

thanks,

TechnoV

[EstorilBlauM3]

I had my VANOS unit replaced which solved all noises. According to my invoice, the part number is: 11-36-1-748-819. The cost for the part was about $280.

[TechnoV]

Do you know if that included the chain? I was thinking that the real issue is probably the upper tensioner which appears to be driven by a hydraulic solenoid.

Thanks for the info.

Technov

[EstorilBlauM3]

The chain was not included. I would change the tensioners first and as a last resort, change the VANOS. Good luck.

[Caymandiver75]

What noise is caused by the VANOS going bad? I have 87k miles on my 97 m3/4 and the car pulls strong. At what mileage are people finding them going bad?

[Cobra Jet]

I only hear a very slight chain noise on cold start up, once the car warms up a little, in a few minutes, there are no noises. I am assuming this is normal?

Can someone please explain more about the VANOS, chains and chain tensioners?

I keep reading about this, but I am not sure what parts should be updated/replaced - there seem to be many opinions on this subject.

Do the tensioners get replaced first, then the chains, then the VANOS unit or solenoid? I'm a little confused.

How does one know if the noise they are hearing is just the VANOS, or just the chains, or the tensioner being worn thus creating chain slack - or all of the above?

How hard is it to replace the tensioners? Does the car need to be timed when replacing the tensioners? If the chain(s) are replaced, does the car need to be timed? What about if the VANOS solenoid is replaced?

Is this something the home mechanic can do, or is it highly advised to let BMW perform this routine?

Any help or more info would be appreciated. I've read the E36 M3 FAQ's, plus other info posted on numerous sites - but none of it is 1000% clear on what precautions should be taken, or preventive maintenance.

It seems there are a few parts within the same general area that can cause the same or similar sounds to the human ear - is it just trial and error figuring out what the EXACT part is making the noise?

Will the part that is making the noise continue to make the noise upon accelration and when the car is warm?

I only hear a faint chain sound on initial cold start up, after that, nothing is audible even once the car is warm and driving at highway speeds, or above highway speeds.

Any help is really appeciated, I'm sure it would also help others to understand this area of the engine mechanics more.

[EstorilBlauM3]

jcolem3 - The VANOS unit in my car went bad at ~75,000 miles. It also went bad again due to defective parts at about ~89,000. Thanksfully, it was covered under warranty from the dealership. The noise is the "marbles in a tin can noise" and can be heard most often when you rev the engine up to about 3,000 RPMs and let it idle down.

In my opinion, the order of replacement should be the tensioners first, then the chain, and then VANOS. Most of the time, it is the tensioners. The replacement of the chain tensioners and VANOS unit are described in the Bentley book so it is possible for the home mechanic to do it with the proper tools.

[TechnoV]

I replaced the lower chain tensioner first and now I am going to take a crack at the upper. It looks pretty straightforward. Is the part number that you referred to just the upper tensioner?

Thanks,

Technov

P.S. The vanos is the variable valve timing unit. It adjust the cam gear slightly during different ranges in the rpm curve thus impacting the amount of air/fuel that gets into the cylinder to produce power. Mine started acting up at 50K miles or so.

[EstorilBlauM3]

The part number I posted is the actual VANOS unit itself.

[Cobra Jet]

What are the part #'s to the timing chain tensioners?

Also, are these part numbers the upgraded parts that can be used on a 95 M3?

[EstorilBlauM3]

Sorry, I don't have the part numbers. I have a 96 so I'm not sure what you are talking about concerning the 95 model year.

[JonUK]

Originally posted by EstorilBlauM3
jcolem3 - The VANOS unit in my car went bad at ~75,000 miles. It also went bad again due to defective parts at about ~89,000. Thanksfully, it was covered under warranty from the dealership. The noise is the "marbles in a tin can noise" and can be heard most often when you rev the engine up to about 3,000 RPMs and let it idle down.

AFAIK, the "marbles in a can" noise on deceleration is just the vanos unit chattering slightly due to it being worn - it's considered a 'normal' noise by BMW and doesn't indicate anything is about to fail, or result in lower power etc - it's just gear chatter.

Other clonking / knocking / banging noises do though

[EstorilBlauM3]

JonUK - I disagree... As did the BMW Technicians who worked on my car... The motor shouldn't have those types of noises.

[JonUK]

Originally posted by EstorilBlauM3
JonUK - I disagree... As did the BMW Technicians who worked on my car... The motor shouldn't have those types of noises.

The marbles in a can noise is pretty common, from my research on the issue (mine does it) it's caused by wear in the gears between the vanos unit and the cam - as they wear, they 'chatter' ever so slightly and cause the noise. Swapping the vanos unit swaps the gear too, hence the wear is gone, so does the noise. As the gear wears, it will come back. Do a search on google / dejanews / unofficialbmw.com for it, you will turn up lots of info.

Unless the gear gets so worn that the chain can jump, it's not going to be a problem.

I believe there's an article on the TIS cd about it too.

[EstorilBlauM3]

JonUK - You are coorect in saying that there would be excess play/chatter between the camshaft and the VANOS unit. When I replaced mine, there was a lot of chatter and under further investigation of the gear on the VANOS unit, it was too much play becasue the teeth on the gears were really worn. Thus, it was replaced. I've heard many M3s with low miles and high miles with the original VANOS unit and tensioners and the motor does not have those noises. Personally, I don't think the noises are normal.

[BrazeauRacing]

Here's a link for the chain tensioner procedure and part numbers...
http://www.geocities.com/rick_poon/tensioner.htm

[JLee]

not trying to hijack this thread but on the topic of replacing the timing chain tensioner

i talk to my mechanic about this and he said yeah its simple but you should remove the valve cover, and there is a tool to lock the cams in place so there is no shifting, cause movement and reinstallation of the tensioner could cause the timing chain to jump ?

does this make any sense ? i was thinking about it too

jeff

[BrazeauRacing]

i talk to my mechanic about this and he said yeah its simple but you should remove the valve cover, and there is a tool to lock the cams in place so there is no shifting, cause movement and reinstallation of the tensioner could cause the timing chain to jump ?

From what i understand, this is necessary for the UPPER timing chain tensioner (valve cover removal and locking tool), but the link i provided is for the primary (lower) timing chain tensioner, which is what causes the 1500 RPM rattle.

I could be wrong though. :

[JLee]

just wanted to post my followup. i went to a CCA do it yourself session hosted by a dealer and one of the mechanics there diagnosed the problem as the belt tensioner. that little shockabsorber doohickey which keeps the tensioner tight was going bad and was creating a chattering sound.

at first i thought it was the primary timing chain tensioner, in fact i even had another mechanic listen to that part (they have a little stethoscope kinda thing) and he said it was that but the dealer mechanic showed me otherwise.

just another option depending on what sound you have and from where

jeff

[JLee]

oh, by the way i fixed it and the sound went away

jeff

[BMWguy206]

This is the reason I dont like diagnosing sound complaints over the net but glad you got it fixed.

Which tensioner was it though.. the one for the AC belt or the for the accessories?

[JLee]

not the one for the a/c belt, the one for the accessories, so while i was at it i replaced the two tensioners, belts and the tensioner itself.

yeah, i mean the net helps point the direction but sometimes stuff like "sounds" etc can be miscommunicated !

but all fixed !

jeff