From one rattle to another - TDI 90 rattle/grumble when engine braking

U

Un4tural

Member
Hi All,

googling about does not seem to have brought the desired results (or anything valuable it seems).

Following fixing the rattly (intake?) pipe seems I've also developed a rattle when engine braking (not related to the pipe it seems, had it before i replaced the bushing and tightened the bracket), will try and record it when i get the chance but seems to be most noticeable in 2nd and 3rd gears between 1.3-2k rpm range... i think i can hear it sometimes in 4th as well but it must be really quiet.

not quite sure where to start as I do not have a ramp it is a pain to get underneath her but missing the underside plastic makes checking things easier (to be put back on when i source a good nick one as it did not come with one).

Possibly exhaust but i wouldn't expect it to rattle when engine braking (fully lift off foot off accelerator, fine when going faster or maintaining speed) - really hoping it is not the gearbox/clutch, it did have clutch replaced right before i got the car as well - but in my mind if it was clutch it would rattle whether engine braking or accelerating... same for gearbox - if pulling hard it should have a rattle same as when engine braking?

Any suggestions on narrowing this one down? No errors on the scan (other than one of the glow plugs being dead according to fault code). will try and capture the grindy rattle on drive home.

Edit: if it is my gearbox crunching out - who have done the gearbox mod with passat 6 speed (i think it was from a passat) how much is that work all in? sounds more worth while if gearbox is on way out.
 
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audifan said:
DMF failing.
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Well I was afraid of this answer - thought it'd be more of a wobble/vibration than a rattle - previous owner did have clutch replaced less than 10k miles ago but did not see mention of DMF on that invoice sadly. Sounds similar to exhaust rattle from friend's A4.

Will go have a look at schematics on how hard it is to replace - would it be something i can get away with on couple axle stands?
 
If the noise stops when you depress the clutch and there's vibration from the car I agree with audi fan it may be DMF. Best get it checked out soon as when I changed my DMF at 94k miles and had vibration and grinding noise the tech replacing said it was close to collapse.
 
murdo said:
If the noise stops when you depress the clutch and there's vibration from the car I agree with audi fan it may be DMF. Best get it checked out soon as when I changed my DMF at 94k miles and had vibration and grinding noise the tech replacing said it was close to collapse.
Click to expand...

There is no vibration from the car - just the clutch pedal seems to be a bit wobbling but only a bit more than accelerating etc. (pressing lightly on the clutch pedal).

It seems to accelerate smoothly otherwise and maintain speed as well. I'll try and remember to record it - it sounds more like something banging against something else than a grinding.

Edit: Slight update - seems clutch pedal vibrates same amount no matter rpm/load (or the rattle) when i put the foot on it lightly. I Suppose i wont know unless i take the clutch off...
 
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A 6 speed gearbox is a brilliant upgrade, thoroughly recommend it. I’ve got a 5+6th conversion and PTW and MYP, the MYP and PTW are my favourites
 
I have the same issue. Rattle when decelarting between 1200 1800 rpm sometimes even when on neutral not driving and just revving the engine up to 2300 release the pedal as soon as it drop to 1800 it starts rattling down to 1200. It's less common in summer had this for over a year and nobody can't figure out what it is. Tdi 1.4 75
 
It sounds like it could be the DMF but I wouldn't start stripping out the box until I had been under the car and given everything a good shake. There are a lot of components in the engine bay and under the car that can rattle on an old car.
Also if you use the brakes to slow down rather than engine braking and your clutch, gearbox and engine will last longer.
 
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bix said:
I have the same issue. Rattle when decelarting between 1200 1800 rpm sometimes even when on neutral not driving and just revving the engine up to 2300 release the pedal as soon as it drop to 1800 it starts rattling down to 1200. It's less common in summer had this for over a year and nobody can't figure out what it is. Tdi 1.4 75
Click to expand...
I have the same issue in my A2, have replaced a lot of parts and any of those did not effect the rattle …
 
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