Timing Chain

[LongmontLou]

When are you suppose to change the timing chain in the 1999 Eurovans? I have 121k miles on the van.

[Jonwid]

Well, ideally, before it breaks, or until you can't stand the suspense. Seriously, I think the 12v VR6 are more vulnerable.

On the very latest AXK 24v for the last model year 2003, I've heard it said that it should be left alone unless there are tell-tale signs that it is having challenges, particularly the "popcorn machine" rattling sound emanating back end of the motor. Ours is approaching 200kmi, still smooth and quiet valve train and all. Touch wood.

[LongmontLou]

[LongmontLou]

How loud is the popcorn noise? Do you have to lift the hood or can you hear it from inside the car?

[Jonwid]

Hood up. At idle. Sounds like popcorn kernels stirring in the kettle before they start popping. It's the plastic chain tensioner guides that have started to break apart and allows the chain links to get loosey goosey and scrape against the walls that makes the sound.

[gakali]

I'd recommend to do them by the time they reach 20 years of age regardless of mileage. The plastic guides are a bit flimsy by todays standards and become brittle and will break away and allow the chains to flop around. VW designed the system for the life of the vehicle and 20 years fits in with that I figure...

I believe that the later 24 valve engines are harder on the drive system due to the increased effort required to turn the cams. The worn off transfer gears you see out there are from the 24 valve engines I believe. My original gear with 240,000 km in my 12 valve '99 looked not too bad, but I replaced it anyway. My guides were partially broken and did make some noise.
_________________
Why do it? Because you can.

1999 Eurovan
2003 A4 Avant 1.8T Quattro
1992 W201 190e 2.3 Mercedes
2006 W220 S600 V12 Twin Turbo 5.5 Mercedes

[LongmontLou]

[Jonwid]

[jjvincent]

Mine snapped off the ends of the tensioner guide rail. As for wear, little if any on the sprockets, rails or chain.

Remember, get a rear main seal because you'll have that cover off and it's super easy to change then.

[my_vw_sucks]

I had to replace the intermediate sprocket on my '97 12v and '01 24v at about 80k miles.

Here's a shot of the sprocket from my '01:

and what it should look like:

[/img]

[LongmontLou]

[jjvincent]

It was going to cause damage if I wouldn't have fixed it. The check engine light came on and when I checked the codes it came down to that both cams were not able to adjust enough. I then tracked the cam timing as requested vs actual and it was off by a few degrees from idle to 6500. Just clearing the codes made them come back immediately. When I pulled the valve cover, there was plastic bits all over the place. So the chain was just sawing it's way through the broken area and the tensioner was fully released. Thus the bottom chain was loose.

[LongmontLou]

[gakali]

[dixoncj]

[dono man]

Hey all, new EV owner here. I just purchased a 2000 GLS on Monday and it's back at the dealer due to a check engine light. It came with a warranty that will cover anything so I'm not too worried but want it fixed right.
My question is what error codes are common with a timing chain/ sprocket related problem? They said it's a misfire code and if it was indeed a tming chain problem it would be a cam or timing error. The service manager is well aware of the sprocket's potential failure.
The EV has 148K miles on it.

[visibleink]

A VW tech told me it will throw a cam error if the chain is about to go. But if you have the popcorn noise that's a sure sign too.

For the misfire - replace plugs/wires, coil pack, and injectors. Trying each one first to see if it resolves it.
_________________
Been on the samba so long I remember petting that dog to see VWs, WYHI, and green bug girl.

<-- Helga, she slammed her dub in '53 and adjusted valves with her teeth

[jjvincent]

You get a cam/crankshaft sensor out of sequence no matter what and then misfire (not always). There's no set mileage for timing chain system failures on the VR6. Some are at 75K and others make it 250K. My neighbors 2000 Jetta 12 VR6 has had the grinding cam chain noise since it hit 60K but no error codes as of yet.

[dono man]

Just got an update;
Timing is on, compression good, impedance on two plug wires off. "We'll replace the wires and install a set of new plugs for you"
Just want it fixed

[Zeddy]

Listen to the van when it idles. If it sounds like a diesel engine, then timing chain may be flopping a bit and overall may be circling the drain. The guides are just plastic, then sprockets wear. The failure is harsh if timing chain snaps.