130 1.9 tdi engine vibration

[FastFerret]

The last week or so there has been a vibration coming from the engine.
Performance is still fine and there is no audible noise just this vibration similar to a dirty injector or a misfire but the pick up and power are unaffected.
There are no codes showing in the VAG reader.

Any ideas anyone?

[mikeybutch]

Does it vibrate all the time incl idle?

[FastFerret]

Hi Mikeybutch,
Thanks for the reply
yes it does and the vibration seems consistent throughout the rev range.
I did an oil, oil filter, air filter and fuel filter change about 12k miles ago with Long Life oil and it was fine until recently.
I do about 3000 miles a month so I am a bit concerned that it may be camshaft or big end bearings about to go or already gone and would hate for it to pack up while i'm on router between Nottingham (Home) and Edinburgh or Cornwall, my furthest clients.
The engine has 116k miles on it of which I did about 85k.
I have checked the pipework for leaks and found none, the turbo seems to be boosting fine and the EGR is relatively clean and appears functional so I am at a loss as to why it is now being shakey.

[Crasher]

Check to see if the alternator drive belt and tensioner are flapping about excessively, especially when the steering is locked over. If it does flap, that is likely to mean the alternator pulley (which is a one way clutch) has failed. They are reasonably easy to replace (much easier if the alternator is off the car) and are not too expensive from GSF.

[FastFerret]

Thank you for the advice, I will check it and see.

[FastFerret]

I checked the tensioner and belt, whilst the belt may need replacing sometime soon all seemed in good order however, as I was having erratic behaviour from the temp. gauge in the car - stays cold and sometimes it suddenly goes to normal temp, nothing in between, I replaced the Coolant Temperature sensor this morning and whilst sorting out the temp. gauge it also seems to have stopped the vibration issue?
Strange I know, perhaps you know why but the engine is back to its smooth old self again. Very strange unless it was sending bad data to the Engine management system which was trying to compensate for a problem that is not there.
I checked the VAGCOM and found no codes for the temp sensor BTW, in fact there were no codes at all which is good.

I must ask though, GSF sold me the Coolant Temp Sensor which is a green one, the old one is a black one 078-919-501-C.
The green one fits fine and works fine but I was wondering why the difference. Was the black (date stamped 12-03) superseded by the green one for some reason?

A brief search through the forums seems to mention Green or Blue as coolant sensors.

[Crasher]

Green replaces black, if the engine gets duff info from the sensor, it runs bad...