screaching on startup

Alternator or drivebelt?

Lasts about 30 - 40 seconds varies with revs and electrical load, stops when sprayed with wd40, could be either but ones a cheap fix the other isn't

cheers

Same as mine - I'm reliably told its my FAN Belt and not to worry... other than it might be too tight.

I need to adjust (slacken off) it to prove this - but at the moment -- CBA.

It is most likely you alternator belt if it is changing with electrical load added and taken off. Basically when you put the rear heated screen, heater, lights etc on there is a greater demand for power, more load on the alternator = squeals more when revd. If it has been noisy like you said I'd recommend replacing the belt as its probably knackered now anyway, they aren't expensive. All you are doing when adding WD40 is lubricating the belt and pulley temperelly reducing the noise, although its still slipping.

Get it changed, their not costly to get fitted either.


Steve.

Ahhh but!,,

Perhaps the wd40 is getting to the bearing that's causing the squeal

Chicken and egg

In 15 years in the motor trade I have never heared a alternator bearing squeal....... grind, rumble and bang yes but not squeal. If it was a bearing then it would get worse due to heat and expansion, not disappear.

WHat you have described is a belt noise, but do check all the running and idler pulleys are free when the belt is off to insure none f the have not seized.


Steve.

Mine squealled like a stuck pig for about a month before the alternator finally went berserk and threw 19V at the battery. It was at its worst after starting the car and moving off. I thought it must be the belt, but it was fine. One replacement alternator later and all was well in my Jimnys world