A4 Timing belt change question

Mickey said:

According to the latest poop from VW the A4 5-speeds are OK for up to 55,000 miles. The automatics require 40,000 mile
changes. If you have a 5-speed you should be OK for a while. Personally, I won't go over 40,000 but that's just me.


I am due for my 40,000 change and the dealer told me 55000. I called VW and they told me for a 99 A4 40000 for 00 and up 60000. (All for manual trans.) I called the dealer back, he checked, and said "Yeah, all TDI 40000" Sigh. So, I checked the TSB's. Did not see one. Anyone know where this information is? Is it real or uban legend. I believe I will just go with 40000, but thought it might be nice to know for sure.

What about the timing? Has anyone found out if the lower number is advanced as I have talked about? I will be recording the before and after timing on my car and would love to know!

Logic tells me that turning the sprocket in the direction of the engine's rotation is "advacing" the timing, since the timing pulses will arrive earlier in the cycle. Observation tells me that corresponds to a HIGHER number from the VAG software. And my sense of hearing told me that when I over-advanced the timing accidentally, pinning the number at 255 (I was actually well beyond that) the engine's clattering was LOUD and violent, due to the injection occurring far too early.

I've given up trying to figure out what the "official" interval is. The numbers I quoted are supposedly containined in some kind of service bulletin, but I've never actually seen it. They are also printed in the owners manuals of the newest TDIs. I'm going to stick with 40K anyway. That's what MY owner's manual says.

-mickey

Wait a minute! I might be wrong. Oh, crap! I was just thinking about it again, and the pump sprocket is the last sprocket in the "line" before the crankshaft. The crank PULLS on the pump sprocket. So "advancing" the pump sprocket towards the crank would introduce more slack into the belt between the two pulleys, which would then be taken up by the belt tensioner.

YIKES!!!! I may have RETARDED my timing! That may explain why my mileage has been relatively poor! That may explain why my car smokes so much! I've might have it RETARDED beyond the spec!

Oh, oh. I need to tinker with it tonight and find out! Nuts. I'll feel like an idiot if I've been telling people how to retard their timing!

-mickey

Mickey, I look forward to your discourse tonight!

And if you do feel like an idiot tonight, trust one who knows, it feels normal to me!

At least we will perhaps get to the bottom of it all! Thanks for not just blowing off my endless questions on this same sore topic. I did send an email to the writer of the Bentley book today. We shall see what he says. I will be doing the 40K change tomorrow. I hope to be able to whine to them about the timing needing to be advanced as far as they can get it. If they change it, that is.

I have a service circular VMS-00-03, which says that for the MANAUL TDI the timing belt change is 60K, where as for the AUTOMATIC TDI it is 40K.

However this circular is for all 2001 cars. I don't think there is any difference between the 99.5's, 2000's and 2001's. I have a 99.5 and am planning to change it at 59K.

mickey:

What you have been telling people is exactly correct.

1. When looking at the timing belt from the right (passenger) side of the car, the belt rotates in a clockwise direction.

2. By moving the pump body in a counter clockwise direction (as viewed from the same position as above), you are functionally turning it farther into its cycle in relation to where the engine is in its cycle. That is advancing its function, and thereby advancing the injection event: it will occur earlier in relation to the piston and cam position.

------------------
Always interested in steep & deep.
Ski resorts closed! Break out the cameras and fly rod ...