Audi a4 2ltr tdi 140. engine has a chatter only when hot . removed aux belt but noise still there. sounds like a pulley chatter. vehicle drives and performs a1.

hot or cold engine or both, is not stated and very very important.
1.6L is a G16B 16valve engine.

1. find a a mech that can do this.
2. did you drop all belts first? run cold cold for 2 min, gone now?
3. use stethoscope to the front timing belt cover, is this it?
4. forget the 60k mile new timing belt , BINGO.?
5. Forget the 60k valve last check and the stethoscope shows, noise on top valve cover. harbor freight sells it for $5
6. is oil pressure at spec, using a real gauge?
7. is the front crank pulley bolt (17mm head) at 94/100 ft/lbs,. BINGO?
8. is the exhaust collector donut gasket bad? (common) sounds just like bad rods too. so while making noise , use a lever and bend the header pipe,(below collector at CAT, lever it, does noise stop.?? BINGO !
9. is the intake pipe on top of engine, not with huge bolts hold it to the exh top rear header tight, many are loose. fix that now.
10. once you prove all this is good, then bad engine.? by process of elimiation. works.

remove the drive belt and check each pulley by hand for drag, or noise. Usually noises from the serpentine belt area are from the tensioner pulley, but since you installed a new PS pump I'd pay particular attention to that-also, watch the belt and pulleys for any 'wobble' too.

The serpentine belt diagram for 1999 Audi A4 1.9 TDI:


CS = Crankshaft
F = Fan pulley
Gen = Alternator
T = Tensioner
AC = Air Conditioning
PAS = Power Assisted Steering


Please do rate my response. Thanks!

The serpentine belt diagram for Audi A4 1.9 TDI:



CS = Crankshaft
F = Fan pulley
Gen = Alternator
T = Tensioner
AC = Air Conditioning
PAS = Power Assisted Steering

The fan belt routing scheme for Audi A6, 2.5 TDI, 150 HP, MY 1999


CS = Crankshaft
F = Fan pulley
Gen = Alternator
G = Guide pulley
T = Tensioner pulley
AC = Air Conditioning
PAS = Power Assisted Steering

sounds like you have a faulty pulley or tensioner. remove belt and spin pulleys by hand to see if they are ruff and see if their is any play in your tensioner.

My sincere apologies for the delayed response.
I am personally going back to answer your unanswered questions.
I have only been a free contributor to this site for the past 4-months.

I do not know if you still need this information, but I am going ahead and answering it anyway.

CLICK on the following LINK. It has several Belt Diagrams, one which will match your specific (AC/No AC, Power Steering, .etc) that you will need. There is also plenty of other Diagrams that you don't need regarding the BeltS. Go approximately half-way and about three-fourths down the page on the Link to see the Belt Diagrams.
You have two (2) Types of Tensioners on your vehicle. You also have two (2) Belts on your Engine.

For the Top Belt:
Using a Serpentine Belt Tensioner Tool or Wrench: Rotate/Move the Tensioner Pulley/Arm (at the Base-located on the top of the mechanism) away from contact with the belt and towards the area where the belt is not in contact with the Tensioner Pulley. The Tensioner is spring loaded, and is hard to rotate/move. Remove the loosened belt off one of the other more easily accessed Pulleys.
For the Bottom Belt:
The Tensioner has a hex-key Locking Bolt to the top-right of the Tensioner. Loosen this locking bolt. The Tensioner Unit will shift, moving the Tensioner Pulley "Up" and "Off" the Belt.

Let me know if this helped...
Again my apologies..

http://www.2carpros.com/car_repair_information/year/1996/make/audi/model/a4/1996_audi_a4_drive_belt_routing_diagram.htm

i have no dash lights coming on so carn't stat it, i drive an 2004 sportback a3 tdi

is it a squeal noise or what? explain more in detail. and yes the belt is directional in that it's path is designed to run in one direction only, no matter which side you put on the belt itself, the belt can be installed in one way or flip it over to the opposite side...doesn't matter, only matters if you installed it correctly on the routing of the belt. And the grooved edge is to be facing down inside the main pulley's that have grooves. If you have the smooth side down into the pulley grooves, remove teh belt and turn it inside out so that the smooth side does not ride inside the grooves of the pulleys.Sometimes, the tensioner pulley will squeal or the idler pulley will squeal when they are going out. If you are actually hearing the fan come on and off, that's normal, the fan is set up to turn on and off according to engine temperature and some cars they continue to run for a bit after ignition is turned off as well to cool the engine down. check to see if the belt is set all the way on all the pulley's it rides on and not partly off on the edge, realign as needed.