Hi all, 

Looking for a bit of advice on some rough running that's suddenly occurred on my 2008 Octavia 1.9 tdi please. This forum has been brilliant over the past 4 years helping me maintain the car but sadly I'm a bit stumped on this one! 

Car has 200k miles on it but has been regularly serviced, did timing belt water pump etc around 2k miles ago. Running great but with the occasional tenancy to idle high around 1100 rpm when warm which is the only issue I can think of. 

On pulling into the drive yesterday the engine suddenly started to sound like a bag of nails (audio attached). No check engine light and no fault codes on the ecu either. I have a BT adapter so if there's further diagnostics I can do to check things please let me know!

Checked the forums and found that the MAF may be the culprit so took that off and gave it a good spray out with some contact cleaner but that doesn't seem to have fixed it either. Seems quite happy to rev but reluctant to do any more miles in it if there's something really up with it, having worries that somehow I didn't torque the bolts up correctly (99% sure that I did) and that maybe the timing has slipped...

Any advice would be greatly appreciated! 

Cheers

Bagofnailsidle.mp3

Having listened to the audio, it sounds a little tappity, but other than that....all good.  Did you fill up from somewhere new? 

When was the last time the timing belt was checked?  You could well have a belt that has slipped.

Have you checked oil level?

1 hour ago, varaderoguy said:

Having listened to the audio, it sounds a little tappity, but other than that....all good.  Did you fill up from somewhere new? 

When was the last time the timing belt was checked?  You could well have a belt that has slipped.

Thanks, just became a fair bit more tappity almost instantly so thought something might be up. Most likely culprit is the timing slip I think, it must have been that I didn't torque it all up to spec fully,  did the job myself in April. I'll strip it down this weekend and report back. 

1 hour ago, Wino said:

Have you checked oil level?

Yes, oil looked good, just under max fill and was changed in April. Would have been a nice quick fix if it was just low! 

Would have to be almost empty-sump low to start making that noise due to oil lack in sump at a standstill, but just thought it was worth asking as you hadn't mentioned it.

How do things look through the oil filler hole, if anything at all can be seen that way? Black-deathy, or nice and light and cleanish, for the mileage?

 

 

What spec oil are you using?

19 minutes ago, Wino said:

Would have to be almost empty-sump low to start making that noise due to oil lack in sump at a standstill, but just thought it was worth asking as you hadn't mentioned it.

How do things look through the oil filler hole, if anything at all can be seen that way? Black-deathy, or nice and light and cleanish, for the mileage?

 

 

 

4 minutes ago, MicMac said:

What spec oil are you using?

 

Oil is fairly dark, but not super thick, figure that's probably par for the course due to the mileage but might be worth a few more frequent changes to clear things out a bit. Been on once a year around 12k-15k miles changes since I've had it which is probably a little too infrequent. I use castrol 5w30 and haven't mixed it

IS that oil rated to VW spec 505 01 or 507 00?

1 minute ago, Wino said:

IS that oil rated to VW spec 505 01 or 507 00?

Can't say I've paid that much attention on that front sadly! Thought going with a good brand and the right W was close enough but I'll check when I get home and let you know. Can you link a list of how to find which it might be? 

It'll be written on the bottle or webpage relating to what you've bought if compliant. 

Kinda critical on the PD engines.

It's not the grade of oil I'm querying it's the spec.

 

You must use VW 505.01 or 507 in a PD engine, typically 5W40/5W30.

 

The sound had me thinking of holed cam buckets.

 

In a diesel engine new oil will look black almost instantly as it mixes with leftover residual oil so you cannot use that for any meaningful diagnosis other than to say it is doing its job of holding soot/blow-by particulates in suspension.

^ My use of the term 'black deathy' wasn't intended to just describe the colour of the oil.

Sludginess with possible crunchy solid residues was more what I was meaning.

4 minutes ago, Wino said:

^ My use of the term 'black deathy' wasn't intended to just describe the colour of the oil.

Sludginess with possible crunchy solid residues was more what I was meaning.

Ah right, deathy as in bits of engine which shouldn't be in bits... will check that over the weekend, thankfully don't need the car very urgently! 

5 minutes ago, Wino said:

^ My use of the term 'black deathy' wasn't intended to just describe the colour of the oil.

Sludginess with possible crunchy solid residues was more what I was meaning.

 

46 minutes ago, MicMac said:

It's not the grade of oil I'm querying it's the spec.

 

You must use VW 505.01 or 507 in a PD engine, typically 5W40/5W30.

 

The sound had me thinking of holed cam buckets.

 

In a diesel engine new oil will look black almost instantly as it mixes with leftover residual oil so you cannot use that for any meaningful diagnosis other than to say it is doing its job of holding soot/blow-by particulates in suspension.

 

Very good to know, honestly I hadn't checked that it was compatible but thankfully I've been lucking out with the recommended on my reg for a while. I take it it's to do with the additives? 

Holed cam buckets, from a bit of light research, looks decidedly full on to address so I think I have a course of action for the weekend. 

1. Oil change - check for bad chunks

2. Timing belt - check timing for slip, correct if so

3. If all above fails, cry into an empty wallet and/or face a full strip down

Thanks for all the advice and help, massively appreciated! 

Will be looking to get things looked at this weekend when the weather allows and will update this thread for any interested parties

I was going to post that timing belts dont slip but as you did the cam belt recently I think there is a very strong chance that the (not) vernier pulley adjustment has moved, they need to be tightened to an inch of their lives.

 

I dont think that there can be valve damage within the possible range of adjustment and the engine will usually not start well before either limit is reached.

 

Ideally you need to fine tune the timing with VCDS after you have got it close with the timing & locking tools, its called torsion angle I think and the aim is to set it to zero, if you find its already at zero BEWARE! It will be a false zero, it only records a couple of degrees either side of the true zero before indicating a default no reading zero, its very very fine adjustment to get it to zero and the figure under measuring blocks should change when the engine is revved, if it doesnt then its a false zero.

 

I apologise because I really havn't explained that well at all.

4 minutes ago, J.R. said:

I was going to post that timing belts dont slip but as you did the cam belt recently I think there is a very strong chance that the (not) vernier pulley adjustment has moved, they need to be tightened to an inch of their lives.

 

I dont think that there can be valve damage within the possible range of adjustment and the engine will usually not start well before either limit is reached.

 

Ideally you need to fine tune the timing with VCDS after you have got it close with the timing & locking tools, its called torsion angle I think and the aim is to set it to zero, if you find its already at zero BEWARE! It will be a false zero, it only records a couple of degrees either side of the true zero before indicating a default no reading zero, its very very fine adjustment to get it to zero and the figure under measuring blocks should change when the engine is revved, if it doesnt then its a false zero.

 

I apologise because I really havn't explained that well at all.

 

Ahhhhh OK, that makes sense, although I sense I'm under prepared and under tooled

to get the adjustment just right! I do remember getting the needle to align but definitely didn't torque it up to within an inch of its life, will make sure I do this time!

I'll do a lot more reading up on this, I feel like I probably approached it a bit gung-ho last time which probably isn't the way to go about a cambelt change...

8 hours ago, Knighty66 said:

Ah right, deathy as in bits of engine which shouldn't be in bits... will check that over the weekend, thankfully don't need the car very urgently! 

No, as in oil residues.

See here for an image or two and some words: https://svsautocare.com.au/vehicle-maintenance/black-death/

I understand that some 1.9PD's had DPF's fitted from around 2008.

 

Do you know if yours has one fitted.

 

Engines usually sound a bit unstable & noisy when doing a regen of the DPF.

Thank you to everyone who helped on this one, I've leaned a great deal and, am pleased to report, fixed the problem.

Timing had slipped ever so slightly so that, with the locking pin in the cam, the crank pin was about 2mm out (pic attached).

Loosened the camshaft nuts with the pin in and turned the crank until pin dropped in. Tightened everything right up and running as normal and thankfully no evidence of black doom or metallic bits in the oil! Got lucky there! 

It will be safe now but you should still get the torsion value checked & adjusted.

12 hours ago, J.R. said:

It will be safe now but you should still get the torsion value checked & adjusted.

 

Booked in this week already, felt like a good idea to get the local garage to check it over! Cheers