This is rubbing me the wrong way - timing belt

Finally got a chance to look under the hood of the wife's car and found this:

I know I now have to go in and try to figure out what could be rubbing against the timing belt - on both sides (hard to see on the photo)...

Anyone seen this sort of thing before? Belt is relatively new... about 27000 miles...

Yuri

PS: I couldn't figure out how to attach a full-size photo... if you click on the thumbnail it should go to the photo server...

I can't see in the picture... is that just a single groove worn away in the belt?

My first guess is likely the same as yours: some foreign object is in there rubbing that one spot away. I know you are meticulous Yuri, and that your last TB change would have been done with care and get buttoned up neatly. Perhaps a little pebble or something got lodged under the crank pulley?

Sorry to hear about your bad luck. At least it isn't January. :/

If I may guess rather blindly: could be a water pump bolt?

I can't tell if it appears on both belt edge, but it's on the back (smooth) side of the belt.
The tensioner, idle roller, and idler pulley (near the water pump) are the only items that run on that back side.

I'm with M. Tranny on this. Something (a too long bolt?) is rubbing against the belt.

manual_tranny said:

At least it isn't January.

Click to expand...

Well, it's over 90 degrees (F) and muggy in the garage...

Lug_Nut said:

I can't tell if it appears on both belt edge

Click to expand...

Yes, the wear patterns are about an eighth of an inch along the back (driver's side) edge of the belt and another groove, about an eighth of an inch in diameter about 3/16" in from the passenger side...

Not going to be a fun evening...

Yuri

A bolt would likely cause more abrasion than that. What ever it is .. it's being picked up by the top roller as well. I would check the other two rollers for possible accumulation of belt dust.

any chance a belt cover clip could end up on the wrong side and line up with the damage?

The usual cause for this is a bolt or screw dropped down into the bottom of the timing belt guard where the head or tip rubs against the timing belt... you may have to remove the harmonic damper and front timing guard to find the little sucker.

Timing belt cover not seated correctly?

The Culprit:



(A bolt similar to that used to hold the water pump...)

The Mystery:

From where did it come? I'm not missing any bolts that I can see... (the front and bottom bolts of the water pump aren't visible, but they can't really come out, as the belt and idler are right in front of them...)

Now to put the engine back together and figure out when to change the timing belt... again...

Yuri

manual_tranny said:

If I may guess rather blindly: could be a water pump bolt?

Click to expand...

ymz said:

The Culprit:



(A bolt similar to that used to hold the water pump...)

Click to expand...

"Soothsayer... say unto me the sooth!!" (P.D.Q. Bach)

So the question remains... where did this thing come from? The bolts holding the crankshaft seal flange are in place, and so is the top water pump bolt...

I guess that since I'll be replacing the timing belt very soon, I'll find out if the other 2 water pump bolts are still there...

Good night...

Yuri

Post a clearer picture of that bolt. It's blurry and the features are indistinguishable.

And, where was it lodged?

And, who replaced the timing belt and water pump last time?

--Nate

I replaced the belt system last January... but there are no surplus water-pump-type bolts around my garage... (when I re-do the job later this week, I'll see if one of the two hidden water pump bolts may have found its way down there...)

The bolt was lodged on the front side of the crank pulley...

A question for the experts: as I was running around from VW dealer to VW dealer in search of bolts that aren't normally included with some kits, I was trying to track down some harmonic balancer bolts (in case I strip one...)

How is the length of bolts measured: is an M8x22 bolt 22 mm long from the tip to the top of the head or to the shoulder of the head? My car needs M8x16 harmonic balancer bolts (and I just located the correct part number on the internet), but the only thing the dealers could come up with are 22mm ones which looked wrong...

Yuri

Bolts lengths are measured from the tip to the underside of the head.

ctnatureboy said:

Bolts lengths are measured from the tip to the underside of the head.

Click to expand...

(slightly off topic: except for flat head (countersunk) screws/bolts, measured to the top of the head. I can't remember if there are any anywhere in a vw, just fyi in general)

It was the front water pump bolt that had backed out...

The replacement bolt will get a drop of LocTite...

What a waste of time... (not to mention money...)

Yuri

11ft.lbs hasn't failed me yet.

runonbeer said:

11ft.lbs hasn't failed me yet.

Click to expand...

You're younger than I am... just wait a while...

Now I found that the water pump is making some noise when turned clockwise... (silent when turned counter-clockwise)... so I guess I'll replace the entire TB system... sigh...

Yuri


PS: I'm sure that I tightened those bolts at least 11 ft*lbs when I last changed the the system...

I'm sorry to hear about this Yuri. Loctite won't hurt anything, that's for sure. I'm going to start using it on all WP bolts from now on.

I wonder if the lack of one bolt could have contributed to the early wear on the water pump? Would the pump rock slightly in its hole, allowing the bearing to be unevenly loaded?

The water pump on my truck failed early 2x before I found the worn tensioner let the belt run off track, causing the faster bearing wear. Different scenario, but similar.

Ah... the old Chicken or Egg conundrum... (Since this car isn't a Hatch-back, I don't know if it applies...)

Yuri