300tdi cam belt failed too soon - why?

jamesmartin said:

when you do a cam belt you set up tighten turn engine over twice and redo ,on the front of crank pulley is a dot which needs aligning with arrow on the case, your bolt if hit a few times weill loosen

Click to expand...

Im not sure as i follow all of that...

I will have turned over the engine more than a few times, when setting the valve clearances. Then i just check the tension(er) again or something else?

The crank pulley (the outer damper or the inner sprocket?) dot? I just tried a google image search (too cold, windy and dark to ventue out right now) but am not sure what you mean?

And the IP sprocket bolt - the rounded one? Whack it?

Thank you.

you set timing, tension belt ,turn over twice ,slacken belt, retension and check marks are fully aligned still, hitting the bolt head loosens it as well as swelling head

I will re-check in the morning.

I dont really understand the method though - ill do it, but i dont understand it.

The leading ridge of a tooth is, what, about 15mm from the leading edge of the next tooth. So, i figure somthing would have to go a long way wrong to go out of alignment enough that the belt needed moving on by a tooth?

Ill look again, but im, basically, certain that the crank and the cam will be spot on, relative to one another, but im just not so sure about the IP with its adustable sprocket.

You need to unlock the IP sprocket before setting the cam/crank timing, once cam/crank timing is set you then set the IP timing,
if you don't do it this way the belt will not have even tension along it's length, so will move when unlocked.

It certanly sounds like a timing issue, be it cam/crank or IP.

The Beast... IT LIVES!


Took off the timing belt again, re-did it all. Loosened off the bolts around the IP. Turned the key - started fine, with no bother.

One bothersome thing, which i dont know is normal -

Took out the keys. Continued to run until i put it in 5th and stalled it.
Started again about 10 mins later. Again ran on after the keys were out, but only for a few seconds, and then stopped itself.

(we're talking normal idle rpm, not out of control)

Need to put back together before running it up to temp.

That's good news mate.

Here's hoping that you get no more issues putting the rest back together.

Took out the keys. Continued to run until i put it in 5th and stalled it.
Started again about 10 mins later. Again ran on after the keys were out, but only for a few seconds, and then stopped itself.

The running on after switching the key off is not normal, you may have a sticking fuel cut off valve, (located on lower rear end of pump), or you are still getting voltage to the valve with the key off. To check for mechanical sticking, start the engine and then pull the wire off the spade coupler of the valve, if the engine stops immediately the problem is electrical.
Depending on what version of what year model electrical systems vary between high spec and base "S" models, can't help you there, both mine are "S's".

Stop solenoid seems to have sorted itself out now, but ill look at the voltages when i get home. It only stuck on twice.

Made a short test drive today, and all seems fine, apart from a bit of an oil leak from the rocker cover gasket (new, OEM fitted).

Id left the bolts really very loose (as they were surprisingly loose when i took it off, and it was not leaking then) so ive tightened them a little, and will see how it goes.


Anyhow, will make another test drive tomorrow - 5hrs from Essex to Devon.
Fingers crossed...

Update (and another question!) -

Have now done about 400 miles since the issue.

Car drives just like it did before, except for two issues -

a) drivers door electric window no longer works
b) different noise from exhaust under load

Now im pretty sure that, even though the window failed at exactly the same moment, its unrelated....



So, point (b) may be unrelated also. But ill go into more detail, just in case -

• The sound is impossible to trigger unless under load. So no static testing (which makes things harder)
  
• It did not show on my brief test drives (before the 250 mile trip back home) but that *may* have been that i was being very gentle.
  
• Now back in Devon, where there's hills etc. its obvious, but its also apparent when pulling away on the flat also, climbing through and past 1500rpm. I dont remember this on my test drives, but, as i say, maybe i was just too gentle.
  
• Noise sounds like its comming from the back, rather than the front. As if somthing is rattling in the boot, but im pretty sure its the exhaust.
  
• Sounds almost like the noise when someone is drinking a drink with a straw, and they come to the bottom of the cup, and start sucking up air. Or when motorcycle engines run at low rpm. Kind of a gurgle / rattle sound.

I went on youtube to see if i could find examples of the sound, and it wasnt easy (i listened to a number of 'exhaust blowing' videos which did not sound the same, and then found this one -


https://www.youtube.com/watch?v=0KFgPB8aiaQ


Its pretty much like the sort of sucking gurgle clicking wrattle at 0:38 in the video above.


What do you reckon then? Coincidental exhaust failure, or something related?

Like i say, the window failed at the same time, so im aware that the two dont have to be related!

Your story sounds like my 200 TDi.
In my case, it was the Head Gasket blown from #4 cylinder to the push-rod hole. This pressurised the sump, forced oil into the turbo (and out of the rocker cover) and the engine started to run-away momentarily, until valves hit piston, bending the push-rods and stalling the cam shaft, causing the belt to jump.
Check that your HG isn't blown by doing a compression test.