Weird rattle! Passenger side. -6.0°KW Camshaft Block 93

[OllieVRS]

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Video says it all. Can only be heard inside the car, with the bonnet open I can't hear it, let alone locate it. Goes away as soon as the revs are above idle. Makes me paranoid it's the cam chain, but I'm not sure as I can't hear it if I stick my ear to the cam chain cover with the bonnet open.

Any ideas lads?

[GVK]

Clutch in /out alter the sound?

[Clarkj93]

Mines always made that noise, not every time on idle but fairly often. Yours sounds a little deeper/louder but could just be how your phone has recorded it or how mine is playing it. A specialist told me years ago they think it's just a solonoid not shutting off properly and not to worry about it unless you get any more symptoms which never happened 4 years later so I just live with it and no issues thus far.

[OllieVRS]

I would think this could be the cause? Up to temp engine. Rattle is inconsistent, sometimes it's there but sometimes goes away.

My engine has a history of low oil pressure, but I'm only after fixing it 1000km ago, could this -6.0KW be caused by low oil pressure again it's something with the tensioner or chain? I know the tensioner runs on oil pressure.

Gonna shamelessly @Pudding here, because I know he's the expert on these kinds of things 

Appreciate it

Edit: Adding a picture of the cam chain, I only checked it 1000km ago and it seemed fine.



128k miles, shoddy service history, probably original chain and tensioner

[OllieVRS]

Once the engine warmed up fully, here's the spec. What's weird is on Block 91 the actual became a bit lower than spec hovering between 25.5 to 26.5 KW. A symptom of the chain/tensioner or something worse?




Anyway, gave it some revs. Goes quiet as revs go up, and clackity as they come down. Scaring me into thinking it's rod knock 

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Anyway, that's all for now. I'll double check the oil pressure to make it's not a factor. Replacement FEBI chain and tensioner, OEM VVT bolt have arrived, just waiting on the cam locking kit and T40080 bit. As always, appreciate all responses 

[OllieVRS]

Oil pressure is still within spec.

Interestingly, throughout my whole oil pressure testing I didn't hear the rattle once!

To complicate things even more, have a look at this:



Back down to -4.0°KW, oil at 85°C.  And block 91 act. is within 1°KW of spec. Self repairing engine?

Mustn't be rod knock then 

[OllieVRS]

Little drive done and she's still at -4°KW, block 91 within spec too.

The rattle stops when I open the bonnet

What mechanisms are affected by opening the bonnet?

[bobby_fodge]

Little drive done and she's still at -4°KW, block 91 within spec too.

The rattle stops when I open the bonnet

What mechanisms are affected by opening the bonnet?

That's odd.

Is the locking mech where the hook on the bonnet sits coming loose?

Have you left a hand tool in the engine bay that the bonnet rests on when closed?

Any witness mark on the underneath of the bonnet from anything rubbing it?

[pudding]

At 128K miles, it could very well be the chain.  The classic symptom of that is a diesel like clattering at a hot idle, which is most noticeable inside the car.

You can't hear it in the engine bay due to all the other noises going on under there, and noises bounce off other hard surfaces and also transmit from one end of the engine to the other, so it's just noise soup under there.

It could also be DMF rattle as it's hard to tell with smartphone microphones, but that you definitely will hear in the engine bay.

I recommend getting a stethoscope from Amazon!

[OllieVRS]

Thanks for the responses guys.

Little drive done and she's still at -4°KW, block 91 within spec too.

The rattle stops when I open the bonnet

What mechanisms are affected by opening the bonnet?

That's odd.

Is the locking mech where the hook on the bonnet sits coming loose?

Have you left a hand tool in the engine bay that the bonnet rests on when closed?

Any witness mark on the underneath of the bonnet from anything rubbing it?

No tools left in the engine bay, good suggestion though.


Started her up today. No tapping sound. Starting to think it's the RAMAIR cone filter's metal edge bouncing off the bonnet, as it's adjusted quite high up to avoid bouncing off the coolant pipe. Although from a not-so-technical inspection it seems impossible, nor did I find any witness marks under the bonnet or on the edge of the cone.

At 128K miles, it could very well be the chain.  The classic symptom of that is a diesel like clattering at a hot idle, which is most noticeable inside the car.

You can't hear it in the engine bay due to all the other noises going on under there, and noises bounce off other hard surfaces and also transmit from one end of the engine to the other, so it's just noise soup under there.

It could also be DMF rattle as it's hard to tell with smartphone microphones, but that you definitely will hear in the engine bay.

I recommend getting a stethoscope from Amazon!

I know what you mean Pudding, but as far as I can tell it otherwise sound like a run-of-the-mill, average mileage TFSi. No diesel sound. I have a friend with a low mileage AXX that runs quieter, somehow.

I forgot to answer this earlier, but being in neutral, pedal in/out or in gear had no affect on the sound on my drive. Sound at idle, sound on over-run, little to no sound on accel. Clutch pedal feels absolutely perfect since my shim fix.

Anyways, on that startup today I logged the degrees again, started off at -4°KW and went up to -6°KW as the engine warmed up. Bizarrely no rattle.

I'll aim to replace the chain tomorrow, because rattle or no rattle, -6°KW means the chains on 'borrowed time', if I can quote you correctly @Pudding

I'll post an update again tomorrow, hopefully with concrete results.

Cheers guys

[OllieVRS]

I've stripped the cam bolt. Man.

First problem was the cheap Chinese cam locking tool's legs were bending.



Second problem was the bolt almost immediately stripped, despite using the correct VW bit. Resorted to bashing in a T55, also didn't work, just stripped it more.

Couple days passed, I've tried drilling the bolt to get a bolt extractor bit in, no luck as the extractor's threads don't want to catch on. And I've now get metal fillings everywhere 

.


Tomorrow I'm going to go buy a 12mm metal drill bit, then attempt to bash in a T60 as one guy has done already on YouTube. That's really my last option, I don't see how else I can do it.

Also, advice for stopping the cams from moving other than the cam locking tool? Thanks.

[pudding]

Don't worry about movement in the cams with the locking tool. That is intentional because you need to tweak the inlet cam anti clockwise a few degrees when fitting the new chain to get the correct tension/timing.

[OllieVRS]

Don't worry about movement in the cams with the locking tool. That is intentional because you need to tweak the inlet cam anti clockwise a few degrees when fitting the new chain to get the correct tension/timing.

No, but the cam locking tool I got is so week that it's legs are getting bent out of shape as I'm trying to undo the cam bolt (as the cam is still rotating). I need another way to stop them moving.

[pudding]

Even the VW tool bends, but not as much as the cheap copies though.  It should hold them still enough whilst you torque up the new bolt and then just move the cams back into the position afterwards. You don't need as much force to torque the bolt as you do to remove it, so you should be OK.

[OllieVRS]

Apologies for the much later than promised update, but as always with car jobs it takes waaaay longer than you expect. I also wanted to confirm the fix with a short test drive from Dublin to Belfast and back earlier today

So, I spent 13 hours drilling out the effing bolt, over a span of 2 days. Yes, 13 hours on one bolt, including three journeys to the hardware store for drill bits. Bashing in a T55/T60 didn't work, it kept slipping out, so it had to be drilled all the way to the base of the head. And the bolt's material was so hard it dulled 4/5 of the 12mm drill bits I bought.


Anyway, enough talking, here's the picture of the bolt after I was done with it (I was nearly crying tears of joy when I finally got it out, it was one of those moments):



Minimal damage to the base of VVT phaser. Disassembled and cleaned out the phaser after with brake cleaner and oiled it up.


Cam chain specs after reassembly, pretty sweet right?:




Also, I think I've solved an old mystery while doing this job. @ROH ECHT and @Clarkj93 you guys might find this interesting, since you guys commented on my post a year ago trying to help. Hopefully this gives some closure, perhaps

Have a look at my cam chain tensioner, notice something is missing?

Not sure if it's placebo, but the engine sounds quieter and I'm not even talking about the mysterious phantom rattle that started this post (which is gone now btw). Just sounds 'less angry'.

That's all. Cheers