Rattle from front of engine at idle

[Roper]

I've got a 3.0 litre 2003 Z4 that has developed a rattle from the front of the engine.

I first noticed the rattle about 18 months ago (not long after I bought the car), since then its got progressively worse. It's definately not valve noise, the nosie is comming from the very front of the engine where the drive belts are located and it's only apparent between 600 & 1000 rpm.

Has anyone had experience this or got any ideas what it could be?

 

[Shipkiller]

Sounds like the dreaded VANOS problem....

Start reading....

http://bimmer.roadfly.com/bmw/forums/e39/7494631-2.html

http://bimmer.roadfly.com/bmw/forums/e39/8705552-2.html

And my problem and fix...
http://www.z4-forum.com/forum/viewtopic.php?f=2&t=3600&st=0&sk=t&sd=a&hilit=vanos

 

[ZetaTre]

Very interesting... I will definitely look into it. Sinco you probably already done the job ( ) could you point out where I can get more informations on how to diagnose the problem. Thanks!!!

 

[Shipkiller]

Most of the info you need is in the first two links I provided...

For me it was the noise from the VANOS at idle and a little surging from 1200 to 2500 rpm.

Here is a forum for those who have done the procedure.

http://bimmerboard.com/forums/vanos/

And another link on the problem.

http://bimmerboard.com/forums/posts/439158

 

[ZetaTre]

I'm not sure why there is no risk to screw up the timing.
Is it because once you remove the VANOS module the two splined shaft here

hold the camshaft connected to the sproket? What's the risk that the splined shaft comes off and you screw up the timing?

 

[Roper]

Thanks guys, it's very much appriciated, but for better or worse I'm not sure it's the vanos.

I've read the links and I don't seem to have the symptoms for the vanos problem. The car pulls perfectly from very low revs (1000 rpm) right the way to the redline. Also the idle is prefectly steady when cold, warming up and when hot. The only change is that the rattling noise gets louder when the engine is hotter!!! The only symptom that seems to be the same as the vanos problem is that the noise is coming from the front of the engine where the drive belts are located.

Thanks again for the help/advice, any further ideas (vanos or other) would be more than welcome.

 

[Shipkiller]

Roper,

You also might have a 'belt tensioner' going bad.

I did not have any cold starting problems also, just slight bogging down in low rpm's.
After I did the Vanos seal repair, I had much less noise from the Vanos.. But the car does run a whole lot better...

 

[ZetaTre]

I'm not sure why there is no risk to screw up the timing.
Is it because once you remove the VANOS module the two splined shaft here

hold the camshaft connected to the sproket? What's the risk that the splined shaft comes off and you screw up the timing?

Anyone?

 

[Shipkiller]

I don't think they will just fall off. I don't remember, but I think they are fastened to the cam shaft by the center hole. I don't even remember them being loose..

I did not have any issues. If you go up the the Vanos forum, I don't think any one else has either.

 

[ZetaTre]

Thanks a lot!!! FYI here's what Rajaie replyed to my question

The timing is not disturbed during the procedure and thus the camshafts and crankshaft do not need to be locked down.
As you point out the helical gears stay mounted to the camshafts and sprockets. This keeps the time set. Even if a splined shaft was removed, as can be done on the intake side, the gears are keyed and the helical gear can be reinserted without disturbing the timing. You would need to unscrew the sprocket mounting bolts to disturb the timing. This is not done in the procedure.

I think BMW/Bentley lock down the timing as a precaution. I don’t see any need for this.
Many have performed this repair without issue.

Another thing: it looks like the clerance between the engine and the support for the radiotor is tight: is it enough? Anything else needs to be removed to make room?

 

[Shipkiller]

Thanks a lot!!! FYI here's what Rajaie replyed to my question

The timing is not disturbed during the procedure and thus the camshafts and crankshaft do not need to be locked down.
As you point out the helical gears stay mounted to the camshafts and sprockets. This keeps the time set. Even if a splined shaft was removed, as can be done on the intake side, the gears are keyed and the helical gear can be reinserted without disturbing the timing. You would need to unscrew the sprocket mounting bolts to disturb the timing. This is not done in the procedure.

I think BMW/Bentley lock down the timing as a precaution. I don’t see any need for this.
Many have performed this repair without issue.

Another thing: it looks like the clerance between the engine and the support for the radiotor is tight: is it enough? Anything else needs to be removed to make room?

I did not know the particulars on that... sorry..

You are correct about the clearance between the engine and radiator. It's about three to four inches. The only problem I had in regards to this is I could not use a pair of needle nose pliers to remove the plastic end caps. I had to use a curved set of hemostats to get the job done, but it was still a problem. The caps are coated with oil and the hemostats had a hard time getting a good grip. The only other thing in this regard (clearance issue) is removing the two vanos cylinder front cover bolts w /washers using a hex key (Allen). Not enough room for the ratchet. So I used a ratcheting box end wrench on the hex key to loosen and tighten them up. You also could use a normal box end wrench.

As I stated on the Vanos site, you may have to disconnect the upper water hose (directly under the Vanos unit) and move it out of the way. Only about a 1/2 pint of coolant will come out. This will depend on the orientation of the electrical connectors under the Vanos if you need to do this or not. I had to...
The coolant hoses are a beautiful design. Just pull the keeper out and remove the hose. NO CLAMPS....

When sliding the fan assembly back in place, the lower right coolant hose will block its downward travel. I used a long metal bar to gently move the hose out of the way to slide the fan back into place.

The procedures he has on his site are very good. I saved them in PDF format then printed them out in Color to use while working...
If you need a copy in PDF format, PM me your email address. I will send them to you.

 

[ZetaTre]

Thanks a lot for the picture!!!! I'll probably do the job in the summer when my dad's around so I have some help... So I have plenty of time to plan out the whole thing... I'll ask more quesitons...

 

[ZetaTre]

More infos from Rajaie, for those of you thirsty of knowledge...

The helical gears on the splined shafts, sprockets, and camshafts have a “key”. One of the valleys on the splined shaft outer and inner gears is filled. It’s a triple tooth. One of the teeth on the sprocket and camshaft gears is missing. It’s a triple valley. These constitute “keys”, and only allow the matting of the splined shaft and the sprocket and camshaft in one possible position.

Thus if the splined shaft is removed and the camshaft turned, the camshaft would need to be rotated back to the original position to be able to reinsert the splined shaft.

Basically even if you remove both splined shaft and turn the camshaft or the crankshaft you can't compromise the timing, cuz the only way to put the splined shaft back is to put the camshaft and sprocket back where they were originally.
Thanks Rajaie!!!!!