TDI 90 engine vibration

U

Un4tural

Member
Hi All,

Fun and games with the little TDI - it always had a little vibration to the clutch pedal, thought it was DMF first which was replaced though did not resolve the clutch pedal, did fix the clutch and DMF that had coughed out the springs though.

Now it has become noticeable worse and i am not sure where to start checking as I'm not super familiar with the innards operation of the TDI, i assume it will be some anti vibration/balancing doodad.

It seems to be worst in 3rd and 4th gear, in 5th can't really feel it at all whether on load on engine braking while it is quire pronounced going through gears from 1st-2nd-3rd.

From the feel of it, seems to be same speed of vibration throughout rev range however it gets worse, more intense at higher RPM. It does same in neutral revving the engine, not tested with clutch disengaged yet though, should've done on drive home (still need to go to work :( ) It is worse in gear than in neutral and in neutral only becomes noticeable over about 2000rpm. with clutch mostly in can still feel it but less still, barely noticeable.

it does sound quite rough when starting cold which goes away quite soon as well, i'll record when i get a chance might be something easy to recognize for some of you guys.

Other than that it Pulls quite well and feels smooth once warmed up, other than the clutch pedal vibrating.

DMF replaced 3k miles ago and it did have the bit of vibration with new clutch as well. Googling for a bit most posts say that it is normal for audi TDIs but i am unsure... it seems to have gotten a bit worse and a bit more than what i'd consider "normal".
 
Halduck said:
Are your CV joints all ok?

Sent from my SM-G975F using Tapatalk
Click to expand...

They seem alright, it doesn't vibrate at speed in neutral which I think would cause vibration if it was cv joints? It vibrates about same in 2nd and in 4th at high RPM and stops as soon as I put it out of gear. Honestly I'd say some bearings near clutch but all those are new along with dmf/clutch. I am a bit at a loss.

Edit: can't say, feels a bit like bearing failing, however there is no funny noise i'd associate with that... bit concerned. Could it be vibration damper - part of cambelt job? I've had this since i had the car but it is noticeable worse now... or some other dampener for vibration, oddly it does not seem to increase in frequency with RPM, just strength, which puzzles me.
 
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A word of warning here

my Tdi 90 managed to snap its crankshaft, at 171k , this was due to it be run with a failed DMF , for well over 40k miles before being replaced

I had only owned the car for 4 weeks at this point , so was rather miffed ..
the only warning , was a sight vibration , at / around 2000 rpm , then a nasty rattle , and the oil pressure warning light came on , leading to a very large engine rebuild

the Tdi , has a balancer shaft , which runs off the crankshaft , this is driven by a chain , and it’s held in tension by a couple of bits of plastic...
those chains , and tensioner have been known to wear , which allows the balancer shaft timing to move , leading to increased vibrations .
the balancer shaft , is at the same end as the cam belt , so opposite the gear box , however , vibrations are well known to “ travel“ and be heard in strange places

the snapped crankshaft , not a lot you can do about it , and no easy way to check , the counter balancer chain , worth changing if the cars got a lot of miles , missing service history, or is due a cam belt change

regards Mark
 
Why did the crankshaft break; due to DMF or the opposite balancer?

It is very interesting tread here; translate page 1-3 in particular:
a2-freun.de

[ATL, Motor] Starke Vibrationen beim ATL – Pumpe-Düse oder doch nicht?

So. Am Samstag ist auf der Fahrt nach München ein Zylinder ausgefallen. Das Auto fühlt sich in diesem Fall sehr seltsam an: Es rumpelt und schüttelt fürchterlich im unteren Drehzahlbereich, Leistung ist deutlich weg, aber wenn man schneller fährt, merkt man fast gar nichts mehr. Keine Warnleuchte...
a2-freun.de
 
Olerype said:
Why did the crankshaft break; due to DMF or the opposite balancer?

It is very interesting tread here; translate page 1-3 in particular:
a2-freun.de

[ATL, Motor] Starke Vibrationen beim ATL – Pumpe-Düse oder doch nicht?

So. Am Samstag ist auf der Fahrt nach München ein Zylinder ausgefallen. Das Auto fühlt sich in diesem Fall sehr seltsam an: Es rumpelt und schüttelt fürchterlich im unteren Drehzahlbereich, Leistung ist deutlich weg, aber wenn man schneller fährt, merkt man fast gar nichts mehr. Keine Warnleuchte...
a2-freun.de
Click to expand...

In my case , I am fairly sure the DMF rattling around the end of the crankshaft for 40k miles would have done long term damage, but we did not check the balancer , the engine was toast , so that’s as far as the investigation works went
 
Well i am worried a bit now, as DMF did go but not sure how long it was going for as clutch went, but i didn't have much complaining from DMF vibrating even though clutch housing was full of spring pieces from the DMF... If that's the case i'll need to keep an eye out for some replacement ATL engines... on the bright side it did seem massaging engine with the gearbox attached is easier than massaging just the gearbox in there with a car jack!

@steveb i am guessing it would be the side of engine with engine mount - where accessories and belts are - any idea how far it needs to be taken apart to actually check condition of it? as it'll be a well nightmare if i need to take half the engine bay out to check for issues...

Bit worried now ?

added oil and it is a little bit smoother, though it might be just me imagining it, it was at bottom of dip stick, shouldn't have made a difference i would expect though...

edit edit: it still vibrates but topping up oil from lowest bar to high end of the line made a big difference... it does feel like a bearing for the pedal but there is no bearing noise, presumably something that does not get lubricated enough when engine oil gets lower... this will be interesting i guess...
 
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