Squealing belts? but only when lights, heating and windscreen wipers are all go

Hi,

I am having problems with a squealing Jimmy. When I drive to work in the daylight no problem. When I drive home in the dark and worse in wet and I have full lights on, heating and windscreen wipers the squealing starts as I pull away at every junction and lasts up until about 25 mph then drops... I approach a junction again slow down and drop the gears and it starts to squeal again. It sometimes also just starts to squeal on a tight corner as I slow down as well. 

I'm just wondering what it is that is causing the squeal - Battery? Alternator? or belts and pulleys? - Is it something that will get worse and cause further damage??

Thanks
Chris.

 

Classic sounds from a slipping alternator belt. It may be the belt is past it's best or it needs tightening or, depending on the model, it may be the drive pulley is breaking up.

Roger

Thanks Roger,

That's helpful. Is there an order of replacement I should look at. For example should l be changing the belt for a fresh one to help me diagnose any other issues while I did that ?

Thanks
Chris

Hi,

It sounds like alternator belt, mine currently has a touch of it in the first few miles, especially at idle and when it is damp. Mine has newish belts and pulley, so it probably just tension.

I would say first check the tension, then the general belt condition and finally the pulley.,it doesn’t take long to check/adjust and if it needs it the parts aren’t expensive. I have a PM from you, so will sort something out soon.

Robin

Check the bottom pulley.

The "design" is very poor, and tensioning the alternator belt tends to rip the outer grooved part (light green) off the inner hub (mouldy green colour)- the inner hub is bonded to the outer grooved part with a thin strip of rubber between the parts (red).
The result at first is that the belt is difficult to tension, eventually when enough of the rubber delaminates, the outer pulley vibrates frighteningly as the engine is revved up, until it eventually falls off along with the belts. Then it is time for the recovery truck as you can't get any drive to the water pump and the engine will overheat.

Try and pull the pulley off, if there is any movement you need a new one.

 

Thanks very much for that advice. I will do some checks again in the light tomorrow. Chris.

Just to explain what is happening for future reference, the more current you need to run your lights, heater, wipers etc. the more the alternator has to 'work' the more it 'works' the harder it is to rotate as it's generating the electricity. Normally what happens is that as you start the car the starter motor takes a chunk of energy out of the battery which the alternator tries to replace, hence why some belts will only squeal for a few minutes until the battery has recovered. I suspect yours has now got past that stage & is slipping even after the that point, it might be worth in the short term until you can look at it, start the car, give it a minute before driving off.

Also check for a slight coolant leak.  Leaks from the top hose or the pump tend to get onto the belts, and it's slippery stuff.

Thanks for that description. That does make a lot of sense in my Jimmy