Has anyone experienced this before?

After about one minute after starting the engine, there is a sort of screeching noise coming from it. Drive for more than a few hundred yards and it goes. All belts, pulleys and idlers have been replaced as part of a full service. Only does it when the engine is cold

If you have experienced this before and know what the answer is I would be grateful

Sounds like an alternator bearing.

Sounds like an alternator bearing.

 

I would go with this also Gazwoz.

The alternator will kick in harder on a cold start and make the unit harder to turn and hence any slack or miss adjustment of the belt will show out. Once the belt catches or the alternator output reduces the squeal stops.

 

So could be a simple case of re-adjustment of the tension on the belt.

 

One issue I saw regular in the workshop was UK sized alternator belt fitted to an import zed. The belt for the import is actually smaller as the pulleys on the fan is smaller. This means the belt adjustment is maxed and still not quite tight enough. The mistake is made when purchasing belts from the UK and the listing is for UK cars only.

 

Alternator bearing would not be on my radar at this point.

 

Jeff

Edited February 26, 20187 yr by JeffTT

When my belts were done it was because their was a noise from that area like a high winning noise and it turned out the bearings in the alternator and air con pump had both sized. Have a good listen to them parts just in case it is them.

 

 

 

https://www.300zx.co.uk/forums/showthread.php?181591-The-lady-in-red-is-back&highlight=alternator

The squeeling wouldn't have come from the bearings themselves, but the belt rubber slipping past the siezed bearings/pulleys. Nonetheless, that's something you can feel for with the belt off, knackered bearings are pretty easy to feel by hand.

Bearings do not get better after a 100 yards or so, the belt is slipping due to adjustment.

 

Jeff

I had same problem after changing belts, had to tighten several times.then all ok .

Guys thanks for your advice on this one, I will keep you updated

had a similar sound on mine,also thought it was slipping belts but when I turned off AC all went quite, back on and noise again, has all gone away for the time being.

might be worth a try if you haven't already eliminated