Something that could happen to a CRD ...

warp2diesel · **Posted:** Sat Jul 17, 2010 8:37 pm

...or timing belt Diesel.

My Wife's TDI had to be towed home after it made a strange noise and lost all power. She was not happy and was stuck at home for four days until I got back. The engine would start but did not have enough power to even crawl along and did not sound right. I suspect the timing had jumped and when I took a close look, I was right. I checked the tensioner and it was in the same position I put it but the belt was slack. I pushed down on the timing belt and the tension was so low that the belt could slip a tooth.
I my case it was the spring in the spring loaded tensioner which I had replaced when I changed the timing belt 30,000 miles ago that went bad.
I installed a new tensioner (PITA), re-timed the camshaft and injection pump and all is well.
One tooth off on valve timing is all it takes to have no power and with the VW TDI one tooth off does not trash the valves.
In the past I have had debris get into the timing belt cog area and do the same on an older VW Diesel.
Once it was bird feathers and another time it was nut shells from feasting squires.
Another cause can be a bad guide roller that we also have on our CRDs.
So, if a CRD or other timing belt Diesel runs lousy, has no power and everything else checks out, check the valve timing, may be the problem.
If any of your covers or guards allow debris to get into the timing belt area, you are asking for trouble.

Sooner or later an uninformed CRD owner will have a basket case that no Dealer can figure out with all the Factory Training and Mega Bucks Diagnostic Equipment. Bet ya they won't check valve timing, but a smart independent shop will.
Good way to pick up a cheap CRD for anyone who is handy with tools.

flman · **Posted:** Sun Jul 18, 2010 6:44 am

I once had a shop do a TDI timing belt for me. A couple of thousand miles later, it was making noise, seems they did not properly torque the tensioner, so I took care of it myself. Lucky for me it did not jump timing.

Joe Romas · **Posted:** Sun Jul 18, 2010 7:42 am

Warp.

Don't you hate it when you do everything right and 30k later bam! Your New Beetle is really fun to work on too :SOMBRERO:

Happened to me 20k later with the water pump I replaced when I did the TB on the Wife's Eurovan 2.5L inline 5 :banghead:

Joe

flman · **Posted:** Sun Jul 18, 2010 7:50 am

Joe Romas wrote:

Warp.

Don't you hate it when you do everything right and 30k later bam! Your New Beetle is really fun to work on too :SOMBRERO:

Happened to me 20k later with the water pump I replaced when I did the TB on the Wife's Eurovan 2.5L inline 5 :banghead:

Joe

They did the WP on my TDI when the TB was done. Actually www.Dieselgeek.com has a nice kit with all the parts for a TDI TB change, WP included

When my CRD hits 100K I will be doing the TB myself, that TDI is so small under the hood, that I had to send it out for the TB job, then yup, go back and fix the deficiencies that come with subbing out the repairs.

warp2diesel · **Posted:** Sun Jul 18, 2010 8:36 am

Joe Romas wrote:

Warp.

Don't you hate it when you do everything right and 30k later bam! Your New Beetle is really fun to work on too :SOMBRERO:

Happened to me 20k later with the water pump I replaced when I did the TB on the Wife's Eurovan 2.5L inline 5 :banghead:

Joe

My Wife blamed the Chinese spring steel in the Canadian built tensioner.
Needless to say, she had a few firm comments at dinner about Chinese lack of Quality.

After I tensioned up the new tensioner, I did the thumb test and could not push it down more than 1/16". With the tensioner that had the bagged out spring, I could push it down 5/8" and at that deflection, the belt can jump time with that little tension.

KJ 119 · **Posted:** Sun Jul 18, 2010 9:16 am

From what Geordi explained to me if the timing belt slips or goes,you'll be in for more than just a belt replacement."Interference" motor design. :banghead:

Joe Romas · **Posted:** Sun Jul 18, 2010 10:43 am

KJ 119 wrote:

From what Geordi explained to me if the timing belt slips or goes,you'll be in for more than just a belt replacement."Interference" motor design. :banghead:

Depends on how how many teeth it slips and probably in what direction. Warp indicated one tooth off.
But if it "goes" then yes :dead:

OldSkull · **Posted:** Sun Jul 18, 2010 11:16 am

warp2diesel wrote:

My Wife blamed the Chinese spring steel in the Canadian built tensioner.

What! G...A critical component like this one use chinese steel! It's a shame! I dont whant to be Canadian anymore ...Wait a minute almost everything is now import from china. What VM Motori use for is engine built in Europe? I bet they use the same chinese B/S like all others do.

Cheap labor rules...

warp2diesel · **Posted:** Sun Jul 18, 2010 11:26 am

KJ 119 wrote:

From what Geordi explained to me if the timing belt slips or goes,you'll be in for more than just a belt replacement."Interference" motor design. :banghead:

One tooth may do nothing more than knock the carbon off the top of the pistons, that is all it does on the older VWs if the engine is not running too fast. My Wife's TDI survived in tact.
Based upon my experience over the years with many interference engines including diesels, I suspect the CRD would survive one tooth, but not two teeth of timing belt slip.
If I get a chance and some time, I will thumb test the belt tension on my CRD.

My employer took it in the shorts with a failure caused by Chinese steel that was supplied to one of our Canadian fabricators. Perhaps they should screen imports from China as well as Canadian Costumes screens me on a business trip to Canada.

dkenny · **Posted:** Sun Jul 18, 2010 3:59 pm

I would think one of the worst aspects of this, should it happen to a jeep, is the fact that the cam gear aren't keyed to the cam shafts. so it would almost impossible to determine with all the special tools..

why didn't they key the cam shaft to the cam gear?

-dkenny

Joe Romas · **Posted:** Sun Jul 18, 2010 4:14 pm

dkenny wrote:

I would think one of the worst aspects of this, should it happen to a jeep, is the fact that the cam gear aren't keyed to the cam shafts. so it would almost impossible to determine with all the special tools..

why didn't they key the cam shaft to the cam gear?

-dkenny

The cam pulleys on VW diesels have never been keyed to the shafts also.

warp2diesel · **Posted:** Sun Jul 18, 2010 4:55 pm

Since the Diesels have less clearance between the pistons and valves, the valve timing is more critical. VW does not key the cam shaft to the cog, instead they use a tapered shaft that locks on from the force generated by the bolt used to secure it. Other manufactures use this trick on diesels also.
You line up the crank, line up the cam with a tool that I have fabricated myself as have others, and lock down the cam in the exact position. This procedure compensates for any errors due to block/head dimensions and timing belt stretch differences.

From what I can see by judging the procedure in the '06 FSM VM uses the tapered shaft system also to align the sprockets to the cam shafts.
"2. Install camshaft sprockets and tighten retaining bolts finger tight.
3. Install timing belt (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT/CHAIN AND SPROCKETS - INSTALLATION).
4. Torque camshaft sprockets to 108 N·m using VM.1085 to hold sprockets."
On the older Mercedes Diesels, they would use offset keys to time the camshaft to the crank to allow for timing chain length or block head dimension errors.
When I do my Timing belt on my CRD in 39,000 miles, I will check to see if the camshafts move any when I pull out the alignment tools. If the camshafts do, I will release the sprockets from the cam and retorque them with the locking tools in place, that way the camshafts will be dead on. Looks like VM does the alignment at 90 degrees ATDC so valves can't be bent if the camshafts need to be rotated with out having the valves hitting the pistons.

Something that could happen to a CRD ...

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