Broken Timing Belt: Valves & Lifters OK!

Hello there.

I mostly just have an update to share. At the end, I'll have a question for the experts or those who are familiar with this issue.

But first, regarding the issue: At average speed (approximately 140 km/h at 3000 RPM), the engine stops responding to acceleration, and everything seems to be going haywire. I tried to turn off the engine, which of course was pointless because it was already off . So, there's nothing more to save. I opened the hood, and saw that everything was full of small, fine dust particles. The suspicion arose that the timing belt had broken, as the other two belts were still visible on their pulleys. So, I called a tow truck to take it home to the workshop.

I took off the cylinder head and saw marks on the pistons from the valves, so I had to get a new cylinder head . It's an expensive undertaking. In addition to that, there are new parts like a tensioner, timing belt, cylinder head gasket, and cylinder head bolts (193 euros). I would have had to wait at least 2 weeks for the replacement head, so I opted for one that my dealer already had in stock, which cost another 500 euros. Now that the head is on, and after the dealer organized the parts and brought a tester to adjust everything, he charged me another 50 euros. So, all in all, it's 750 euros for practically nothing.

Okay, here's the translation:

'So, now to my question: The timing belt had been used for 40,000 kilometers and was most likely worn out unevenly. In the end, it was only half as wide as the original. Shortly after that, it broke. My suspicion is that the pump mounting bracket is bent, which allows the timing belt to slip on one side.'

Can anyone confirm this, or is it something else?


Best regards, Wolle.

Hello,

What kind of engine do you have? Was the fuel injection pump properly tightened, including at the back where the fuel lines come out?
Is the water pump mounting okay, in case it's driven by the timing belt on your engine? Has the pump bracket ever been detached from the block?

Driving with a timing belt that is half the correct width is extremely reckless. Why wasn't it replaced?
The new dimension for the width of the timing belt on AHF & AFN models is 25mm. The wear limit is 23mm.
That should give you something to think about.

Best regards, Rainer.

What kind of engine do you have?
-AFN.


Was the fuel injection pump properly tightened, including at the back where the fuel lines come out?
- Yes, everything was secure and is now back in place.

Is the water pump mounting okay, in case it's driven by the timing belt on your engine?
- The warehouses are okay.

Was the pump console ever detached from the base?
-The pump console has never been unlocked.

Driving with a timing belt that is half the correct width is extremely reckless. Why wasn't it replaced?
The new dimension for the width of the timing belt on AHF & AFN models is 25mm. The wear limit is 23mm.
That should give you something to think about.
- So far, I've been able to drive without any issues until the next scheduled timing belt replacement. I didn't notice that the timing belt was deteriorating because I hadn't checked it. The engine now has 230,000 kilometers on it. Since I've owned the car, it has had two voluntary timing belt replacements and now one involuntary one.


Well, you learn from mistakes, and I'm going to check that damn thing every few weeks now.

Hello,

Quote:

In the end, it was only half as wide as the original. Shortly thereafter, it broke.

I understood that you noticed he was narrower than usual, and yet you continued driving.

Is the bearing of your fuel injection pump shaft in good condition?
I consider it impossible for the ESP bracket to bend during operation.
What do the tensioning and guide rollers look like?
Are there any signs of wear or abrasion on the timing belt flank?

Best regards, Rainer.

'No, if I had noticed that it was narrower than necessary, I would have replaced it immediately. But as I said, I've never experienced anything like this before. There are only signs of wear on the vibration damper. When I removed it, there was quite a bit of rubber residue on it. The edge was slightly sharp. I mean, that sharp edge probably came from the contact with the timing belt. I then carefully and neatly smoothed it out and reinstalled it without any sharp edges.'

Hmm, I'm not sure now if there isn't a starting plate for the timing belt on the pulley for the serpentine belt; I can't remember.

Hmm, I'm not entirely sure now, but maybe there isn't a starting plate for the timing belt on the ribbed pulley wheel; I can't quite remember... No, there is no starting plate. The timing belt normally engages slightly against the vibration damper. That's why the engine should never be started without it. The probability of the timing belt slipping is too high and can almost certainly happen.



I removed the timing belt cover again and noticed that the timing belt is already starting to sag towards the bumper after only 500 km since it was replaced. Upon closer inspection, it's also visible that the belt moves slightly outwards from the water pump pulley. However, neither I nor my helper could detect any worn-out bearings. It's also possible that the belt starts moving outwards from the fuel injection pump, but this is not easily discernible with the naked eye.

Is there anyone here who has experienced this or a similar problem before?
I would be very grateful for reports or solutions.

Regards, stream_2.