What damage ?

If nothing showed up on the dash, I'd guess none. In cold weather, once you get moving the fan could be superfluous anyway. Mike.

I ask this because a while ago my fan belt dropped off and a couple of weeks later I started losing power, getting worse over about a week until it would crawl along at 5 mph. A new ignition pack cured it. Didn't know if it was connected.

Unbelievably, The fan belt came off again a week ago and today I noticed a lack of power again.

Em, it's an Astra...it's not actually a 'fan' belt. He means the aux belt, that drives the alternator.

It won't cause any damage, but the engine management system will be running entirely off the battery. This means when the battery eventually runs out, the engine stops. Head lights, stereos and heating fans all contribute to battery weakening.

If the belt's constantly falling off, make sure the tensioning bar isn't bent, pushing the alternator in or out a bit causing it to pop off.

I can't see how the loss of a fan belt could affect the ignition pack.

If it overheated, I could understand it affecting performance. Blown head gasket etc. If it didn't I'd be inclined to say it's just coincidental. Would be a strange coincidence though, having it happen twice. Mike.

Fan belt or auxilliary belt, I can't see a failure of either causing any harm to an engine or ignition system. Just the possibility of overheating in the case of a fan belt. Mike.

Must be a well serviced car...

The loss of belt would give no charge, when the battery is low enough the ecu 'may' go into limp home mode.

I don't understand how you could miss the warning light for charging?

Mrcheerful

Or a damaged battery from deep discharge.

Bob

The lack of power was probably when the battery was nearly flat, and there was not enough juice in the battery to make a nice fat spark.

Did the red battery warning light not come on?

Bob

No damage to electrics.

You dont mention exact car, but if the water pump is aux belt driven then you do risk overheating it and causing damage that way.

Tim.

First thing I did was put a new battery on. I hear what eveyone is saying, but I can't believe its just coincidence that I get exactly the same problem after driving with no fan belt twice. It must damage the ignition pack in some way.

I knew the belt had gone and it wasn't charging, but I thought like everyone else so far that apart from a flat battery there would be no damage driving it home. Changing the ignition pack cured the problem and I thought it was a coincidence , but after the belt went the second time I have got exactly the same symptoms starting. Today it has slowed down some more and by the next couple of days it will be undrivable. Driving on battery alone must damage the ignition pack.

So why didn't you fix the fault with the belt the first time it came off, rather than drive it till it stops, then repeat ? If you can't afford the maintenance, then get a bus, you are a danger to other road users and yourself. If you can't afford to have the car off the road while it is fixed, then get two cars or hire one while your primary car gets fixed.

Mrcheerful

Reminds me of an incident I had - going into town one evening, thinking hmmm - lights look a bit dimmer than usual, wipers seem slow - oh bugger, battery not charging. Took a different, more populated route home awaiting the inevitable. Driving along, wipers stop, push bike light brightness, try to indicate to turn off and engine finally quits

- as I coast into a pub car park.

Would the wife believe me!!

" Where are you? " - " Broken down, in the pub..... "

Mind you, the RAC weren't much better - why can't they accept your explaination. When I say "it's the 15amp female spade crimp to the alternator that's failed" do you then spend 15 mins answering inane questions on the phone - "are you out of petrol ?" ....grrrrr

( snipped-for-privacy@AOL.com) gurgled happily, sounding much like they were saying :

I've had this conversation with one of their rescue contractors...

Simple answer? Because very often they get people who are absolutely

It doesn't. And it didn't the first time. HTH.

It's difficult to be sure, most of them cut out at low voltage but some thing do die if you run them at a low voltage.

It's a Vauxhall petrol engine. I have seen and done worse things and they've survived.

The ECU would stop switching long before the voltage reached any sort of danger threshold for the pack.