Is this the dreaded Cam Chain failure!!!

Dan-1981

Dan-1981

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Evening All,

I was asked by a member to video my car doing a cold start up.

Mine has been sat since Sunday night and was started this evening, and after playing the video back, does it sound like a chain is on it sway out?

I have never really noticed it, nor paid attention until I recorded this for Nathan.
 
Mine sounded like this for years, and it wasn't the chain that actually failed it was the tensioner. It sounds like one of your tensioners have collapsed and the chain is just rattling around in there.

Does the sound go away when it's warm? The way they are designed (hydraulic tensioner) means that until the oil circulates they don't tension that well either so you can hear a rattle on start up.

This is what the chains look like:
d1beebc40c22301d3cfe16dde6e7e13d.jpg

What happened to mine was that a piece of the chain guide broke off, wedged itself between the chain and cam gear, causing it to jump a tooth, causing the valves to get up close and personal with the pistons.... if you have a chain failure or chain jump you won't be able to start the car. It flags cam out of position. If it fails while you are driving however you will hear a ticking sound (valve hitting pistons) and it will keep running, until you turn it off, then it is dead in the water...
 
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****** hell, I have only heard it when I filmed it for Nathan, and today me and a mate were listening when I flashed it up and nothing. Might just get the garage to do it and save the pain. Do you change both or just the one that you can access from the engine bay?

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I can't say which ones you should replace. That is entirely up to you and what risk you want to run.

As I said the guide was the primary failure on mine, followed by the collapse of the tensioner when the piece of the guide made its way through the chain/gear meshing.
 
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fair point, don't suppose you have any part numbers or links to sourcing the chain and tensioners.
 
Presuming this is a BKN engine?!

Timing Chains and Tensioners

AUDI
upper centre chain (059109229J)
£67.84
no. 21 tensioner (079109467AE)
£44.28

left chain (059109229L)
£67.84
tensioner (059109217C)
£173.47
guide (059109469E)
£17.98

right chain (059109229K)
£67.84
tensioner (057109218K)
£173.47
guide (059109469F)
£17.98

lower chain (079109229D)
£67.84
tensioner (079109507G)
£59.08
guide (079109510M)
£33.84

TOTAL £791.44
Next day if ordered before 3pm

You can get these cheaper if you don't want OEM places like ECP should stock them.
 
legend, how can I ID the engine? is it marked in the engine bay?

Did you go for OEM?
 
I did, I replaced the valves that clashed with the pistons as well. I only went OEM because it's such a PITA job to drop the whole Powertrain and split the engine/transmission to do it I thought I am going to do it once and once only and use OEM parts
 
Doesn't sound like chain rattle to me, mine sounded much different, two second rattle on start up then fine.
 
audi upgrades
I would still say tensioner then, I'm no expert on whether it is or isn't though especially without actually seeing/hearing/feeling it.

You can use a long screwdriver as a stethoscope to pinpoint the location of the rattle. A simple YouTube search will explain exactly how to do it.


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Perfect cheers dude. The lead tech at my local Audi did a thorough health check for me before investigating the rattle. They are pretty confident it is that tensioner causing the noise so fingers crossed it solves it!
 
Is the top left the one you can do with the engine in the car or did you diagnose that chain?

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Dan-1981 said:
Mine is on 127k and a map was applied last year.
Click to expand...

Hmm I would definitely check the crank bearings then, that's quite high mileage to be sticking a remap in at and expecting everything to be ok... the tensioner rattle I would expect to go away after it's warm. Take the undertray off, and have a listen to the underside of the engine, use a stethoscope or screwdriver as a stethoscope and see if it is louder on the engine sump or on the top of the engine.
 
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Mate, if I tried it I would end up taking the wrong side off and putting it back with the chain still on the bench.

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OliNix said:
Mine sounded like this for years, and it wasn't the chain that actually failed it was the tensioner. It sounds like one of your tensioners have collapsed and the chain is just rattling around in there.


Does the sound go away when it's warm? The way they are designed (hydraulic tensioner) means that until the oil circulates they don't tension that well either so you can hear a rattle on start up.


This is what the chains look like:

What happened to mine was that a piece of the chain guide broke off, wedged itself between the chain and cam gear, causing it to jump a tooth, causing the valves to get up close and personal with the pistons.... if you have a chain failure or chain jump you won't be able to start the car. It flags cam out of position. If it fails while you are driving however you will hear a ticking sound (valve hitting pistons) and it will keep running, until you turn it off, then it is dead in the water...
Click to expand...




Hi Oli,


I have similar situation with my Q7 (3.0TDI 171kW, BUG), engine not cranking at all...

How did you split engine feom transmission as there are bolt to torque converter accessible through starter hole and I cannot turn the crankshat at all.

How did you set up timing after all parts were out of alignment (again I cannot lock any of shafts or pulies as engine is ot turning)

Thanks.
 
Darek said:
Hi Oli,


I have similar situation with my Q7 (3.0TDI 171kW, BUG), engine not cranking at all...

How did you split engine feom transmission as there are bolt to torque converter accessible through starter hole and I cannot turn the crankshat at all.

How did you set up timing after all parts were out of alignment (again I cannot lock any of shafts or pulies as engine is ot turning)

Thanks.
Click to expand...

First, how have you determined this is a timing chain issue? This could be a seized oil pump which in turn has seized your crank and it is goodnight Vienna to the engine from there.

When timing chains fail you can still turn the engine. Mine would crank indefinitely but just never start.

If you are sure it is the timing, is the engine still in the vehicle? It is not that much more work to drop the engine and transmission as one unit and reassess the situation. That is what I did. There are several bolts on the top of the bell housing which I don’t think are accessible with the transmission in the car.

Once the whole powertrain is out you can actually pull the transmission and engine apart without disconnecting the torque converter. You just can’t reinstall it this way. Make sure to fully support the engine and transmission so as not to leave it pivoting on the torque converter.

How have you attempted to turn the engine? You need a tool which locates to the TV damper on the front of the engine? Then with this you need a fairly long bar to turn it. This tool comes with the timing kit which you will need later on to retime the engine correctly. You can get the whole timing kit for around £40 on eBay... I’m sure you could find just the crank turning tool as well.

It is pointless to retime it if it is seized, it’s probably quite terminal as I have eluded to before. If you are 100% sure it is seized and you want to repair it then I would suggest to remove the heads to inspect the valves to make sure 1 has not broken off and jammed itself in between the piston and bore (this is definitely terminal). If it is just a broken valve stuck between the piston and head this may be able to be salvaged, and as you have the heads off you will now be able to turn the engine.
 
OliNix said:
First, how have you determined this is a timing chain issue? This could be a seized oil pump which in turn has seized your crank and it is goodnight Vienna to the engine from there.

When timing chains fail you can still turn the engine. Mine would crank indefinitely but just never start.

If you are sure it is the timing, is the engine still in the vehicle? It is not that much more work to drop the engine and transmission as one unit and reassess the situation. That is what I did. There are several bolts on the top of the bell housing which I don’t think are accessible with the transmission in the car.

Once the whole powertrain is out you can actually pull the transmission and engine apart without disconnecting the torque converter. You just can’t reinstall it this way. Make sure to fully support the engine and transmission so as not to leave it pivoting on the torque converter.

How have you attempted to turn the engine? You need a tool which locates to the TV damper on the front of the engine? Then with this you need a fairly long bar to turn it. This tool comes with the timing kit which you will need later on to retime the engine correctly. You can get the whole timing kit for around £40 on eBay... I’m sure you could find just the crank turning tool as well.

It is pointless to retime it if it is seized, it’s probably quite terminal as I have eluded to before. If you are 100% sure it is seized and you want to repair it then I would suggest to remove the heads to inspect the valves to make sure 1 has not broken off and jammed itself in between the piston and bore (this is definitely terminal). If it is just a broken valve stuck between the piston and head this may be able to be salvaged, and as you have the heads off you will now be able to turn the engine.
Click to expand...


Thanks for answers.
I have order the timing tool and will try to turn crankshaf. Battery drains after cew attempts to start the engine. I could hear click and half second humm (like starter would try to turn the engine) and thats all, movement.
Engine is still in, I have started taking front parts away for access, I need to find what is happening with engine first. Would be great if it would be repairable.
 
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