Technical Infernal squeaking JTD

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Technical Infernal squeaking JTD

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Gerrard has for a long time made an irritating squeak/chirping from the motore at idle or just off idle. It sounds like a bearing or belt... but I'd say more "dry bearing" than belt.

No problems, thought I. The beast received a new cam-belt and water-pump, along with tensioner and pulley... AND while matey mechanic was at it, they also fitted a new Aux belt.

Due to a leaky O-ring, I had to remove everything to replace the O-ring.. so at that time I lubed up all the re-used aux-belt pulleys and I fitted a new aux-belt tensioner. I couldn't identify any component that looked too old, worn or noisy.

For a day or two, everything was silent and I was happy.. :D but the squeaking has come back, possibly slightly worse than before just to **** me off.. :D and I'm at a loss to understand what it is.

It's definitely engine (rpm) related and not anything to do with clutch, transmission or suspension... since it chirps at idle and the noise goes away if you blip the throttle.

I lubed everything to buggeration and it hasn't made any difference. I couldn't isolate the sound when I had my head in the wheel arch..I suspected the air-con compressor but the sound was not from there..?

Does anyone know this sound and has ever worked out where it comes from?

The only thing left that I feel I haven't checked, or lubed up is the alternator (hopefully it's not wonky bearings... ) but if I was going to grease it up, where's the best place to squirt my lube, so to speak? As above, aux belt and tensioner are new and I even put a bit of lube into the tensioner (the plastic sheet between the fixed and sprung parts).

Where's it coming from...?

Ralf S.
 
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I had the same issue with my 156 JTD. It turned out to be the pulley of the alternator. It has a one-way 'gear'. So it should slip turning it one way and hold/grab turning it the other way. If the auxiliary belt is removed you can turn the pulley and feel it slipping turning it one way. If it's fixed to the shaft the one-way gear is worn.
Another way of checking is looking at the alternator when turning off the engine. The alternator should run a while after the auxiliary belt and pulley have stopped.
 
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