Alternator pulley snapped and boiled over - advice please?

[CheekyRich]

Hi

Had some work done at my local garage on a 2.5 diesel which included tightening drive belts.

A few miles later the day after collecting the van, the sediment and charge lights came on and the temp gauge showed high. Haydn coolant alarm had not gone off. I pulled over and stopped the engine. A few seconds later the coolant boiled over.. heard a rumbling gurgling sound and lots of steam. Shortly afterwards a higher pitch sound started and I could hear a lot more steam / pressure escaping as though a pressure release valve had opened (or something had blown?)

Called a breakdown service and and the van went on the back of a recovery truck.

Looking in the engine bay I can see that the alternator pulley has totally sheared off.. shards of metal in places and the pulley is lying on the underbody tray so it's clear what has happened. The two alternator drive belts are still there, just with no tension or drive because of the snapped pulley.

I caught it just before the boil over. What work / checks need to be carried out from here to put things right (beyond a new alternator or pulley)? Is there any possibility of head damage or any other damage? Anything that needs to be checked or done? All maintenance had been done up to this point and never had any problems if this nature.

There is now no coolant in the expansion tank and the coolant alarm goes off as it should.

Thanks in advance...

[gilly99]

It's a common problem that the alternator pulley disintegrates, usually during teardown to change the timing belt, service or generally changing or tightening belts. I think the A/C pulley has a similar weakness.

I'd be quite hopeful - you could well be lucky, as sounds like you caught it straight away and your coolant alarm did its job. Would think much better to trust a Bongo specialist garage for this work, but needs a pressure test for each cylinder to hopefully confirm there is no obvious head damage for example. One thing important to note, is the debris from the pulley get everywhere including in the timing belt/flywheel area so if you are indeed lucky and it's just replacing the broken parts, belts, flush and bleed the coolant etc, I would think it advisable to change ALL belts including the A/C belts (& its pulley) and probably the timing belt while your there. Also, a deep check of the entire coolant system, pipes & hoses etc, but any decent Bongo specialist should be all over that after your incident.

[CheekyRich]

Thanks for your comprehensive reply... All fixed now but your assistance was massively appreciated when in the lurch!

It's a common problem that the alternator pulley disintegrates, usually during teardown to change the timing belt, service or generally changing or tightening belts. I think the A/C pulley has a similar weakness.

I'd be quite hopeful - you could well be lucky, as sounds like you caught it straight away and your coolant alarm did its job. Would think much better to trust a Bongo specialist garage for this work, but needs a pressure test for each cylinder to hopefully confirm there is no obvious head damage for example. One thing important to note, is the debris from the pulley get everywhere including in the timing belt/flywheel area so if you are indeed lucky and it's just replacing the broken parts, belts, flush and bleed the coolant etc, I would think it advisable to change ALL belts including the A/C belts (& its pulley) and probably the timing belt while your there. Also, a deep check of the entire coolant system, pipes & hoses etc, but any decent Bongo specialist should be all over that after your incident.

[gilly99]

Great news indeed!!! I am uber paranoid about two things - the cooling system and the belts!!!, so only entrust those to myself or a bongo specialist. For everything else maintenance-wise, I think your local garage is probably fine.

As you probably now realise the temp gauge is near useless for even a hint of an early warning. For information, there is a mod on the forum / tech sheets to make the temperature gauge more sensitive by bridging a resistor diode to the gauge - looks a simple enough job, but obviously the gauges have to come out of the dash - I have just never got around to doing it.