15K After Chain and Tensioner - Warm Rattle Returns!!

[f00glee]

Had my chain and tensioner done 15k ago (at ~30k). Nose was there before and disappeared after. Great, I thought.

Now in the last few weeks a similar noise has come back, only when hot idling, sounds like coming from passenger footwell but not easily audible under the bonnet. Took to the garage, mechanic confirmed sounds abnormal and we probed around with a stethoscope. The cam chain/fuel pump/vacuum pump area shows some signs of the rattle in the background when resting the stethoscope on these caseworks but not as loud as we'd expect. The thinking is then it may be somewhere else. Possibly even the chain driven oil pump at the bottom of the engine, for similar reasons as cam chain i.e. oil thinning so not enough pressure in tensioner any more.

We ran out of time yesterday but they are pricing up a sump drop and the cost of oil chain/tensioner and sprocket in case it does need doing. I'm a few months out from an oil change anyway so may as well have a look and at very least get fresh oil out of the cost of investigation.

Anyone have any further thoughts?

Poor iphone audio recording taken from in pass foot well 1000rpm-1500rpm-idle.
https://vocaroo.com/i/s1AuqYBe9LXE

[pudding]

Sounds like knocking to me.  At those rpms, a likely suspect is the DMF. Is it a manual or DSG? If the former, another suspect is a worn layshaft bearing in the gearbox.  It’s a rotational clattering noise that disappears when pressing the clutch down.

[f00glee]

Hi Pudding, thanks for the reply.

It is a manual car, but the noise does not disappear or get any better/worse with clutch position or engine load e.g. when pulling off. Would flywheel still be a candidate? and would flywheel noise come and go with engine temperature?

For now I am proceeding with a sump drop to have a look at oil pump chain, seen a couple of reports of these failing.

https://www.briskoda.net/forums/topic/424418-blaggers-guide-to-tsfi-bwa-internals-pt1-sump-removal/?tab=comments#comment-4816550

http://www.mk5golfgti.co.uk/forum/index.php/topic,97675.msg989519.html#msg989519

@Carpy25 you still active on here? Your profile suggests you might be!

[pudding]

I have both of the noises mentioned above and I did my chain a year ago, so unlikely to be that in both of our cases. My DMF is especially bad when hot at the rpms you mentioned. The joys!
DMFs can wear out in two planes. Laterally (my issue) or rotationally (worn/broken springs). The latter tends to make a knock/rumble at low rpms at any temperature. 

I’m not sure about the oil pump chain tbh. The only issues I’m aware of down there are pick up pipe blockages and the oil pump sprocket bolt shearing off.  The latter only affected really early TFSIs iirc. 

If you suspect the chain, you could look up channel 93 in VCDS and see what the ‘phase angle’ is. Acceptable range is +1KW to -4KW.  If its much higher than that, the chain is worn or a tooth off.

[f00glee]

Ill take a look at block 93. I really don't think the noise I have appears to be from the timing chain this time (which as I say was replaced 15k/2 years ago), but worth checking out. Is this test done at idle? Further hunting for the real source of the noise to follow.

Currently booked in to have sump dropped next Tuesday to have a proper look at the oil pump chain area.

How did you diagnose your DMF?

[pudding]

Yep, at idle.

It’s the only thing that can be making the noise I’ve got 

[coolhandluke]

Prospective buyers will come across this forum read these posts and run a mile and we will be left stuck with them wether we want to or not.

[99hagued]

When it’s making the noise get someone to push/pull on the fuel pipes under the bonnet where they run down the bulkhead well you sit in the car and listen if the noise goes. Might be a long shot but it’s common on these cars for the fuel pipes to rattle and it sound just like the timing chain rattle. My ed30 started doing it a few years after doing my chain and this was the problem.

[f00glee]

Good point 99. I do hear the fuel line rattle from under the floor behind the drivers seat when the car is very warm sometimes, but in addition to this other main rattle. I actually ordered the little rubber spacers to solve this today so will be sure to have a good root round while I fix this at the weekend. I’ll be sure to make sure the fuel lines are secure along thier whole length.

I intend to get under the car with a stethoscope at the same time to see if I can track the noise down.

I’m 99% sure this isn’t the main rattle, but it would be very nice if I were wrong!


Sent from my iPhone using Tapatalk

[pudding]

Good shout on the fuel lines.  It's an easy one to forget!  I used some grey pipe lagging foam from B&Q to silence mine.   They tap on the chassis leg just behind the front wheel.  You will see the offending area after you've dropped the plastic floor liner down.

I've listened to the sound clip again, through my desktop speakers this time.  It definitely sounds more like a deeper, mechanical knocking than plastic lines tapping the floor, but it's always hard to diagnose sounds accurately on the internet.  It does still sound like a DMF to me, and it's in the right area to be a suspect, but obviously I can't be 100% certain. 

[f00glee]

Thanks for all the replies.

I was booked next tues for sump drop and inspection with potential to replace oil pump chain if needed. I was happy with the inspection cost, and happy with parts cost for chain and tensioner if needed. But today they've realised its a cam belt off job to swap out the oil chain if needed, pushing the cost past where I'm comfy for what is still a bit of a guess. I can see for potential for "the chain looks a bit slack", work being done, and still no improvement.

For now I've put the job on hold till I can have a closer look myself tomorrow. I'm gonna get under the car and fix the fuel line rattle and have a good root around with a stethoscope. Also taking into account all suggestions above re:phase angle measurement to further rule out cam chain again. If after all of this the oil chain is still the prime suspect ill just have to bite the bullet.

 

[f00glee]

@Pudding  checked phase angle with VCDS. Cold engine at idle read -5kw stayed like this for 10 mins. After a half hour drive to tps and back re read and it’s sat at -2kw. Also looked at block 91 and did a quick log of continuous adjustment vs specified and they follow each other nicely when revving the engine.

Normal?

The rattle I’m concerned with again wasn’t there until warm. After getting home and being stationary for a few mins the fuel line rattle crept in too. Next job is to tackle fuel line rattle then have a good listen around the bottom of the engine.


Sent from my iPhone using Tapatalk

[pudding]

Yep, that’s fine. No need to bother with cam chain 

[f00glee]

 

None the wiser as to the source after a few hours of prodding.

Ill go for a second opinion as
t a well regarded independent guy next. If at that point I don't have a good answer ill be living with it till it worsens to a point where it can be pinpointed.

[muff1991]

what about the cam chain adjuster... read a post someone had the chain and everything done but the noise was still there.. turned out to be the adjuster. (apologies if my penny is voided as I have read the full post)