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MG MGF Technical - auxiliary belt

My 1998 steptronic died on the M25 last weekend. The RAC took the car to my local garage saying that he thought the cam belt had snapped. The car has 40000 miles on the clock and the cam belt was changed in July 2005 some 15000 miles ago, also the car was serviced two weeks ago. The garage has contacted me to say that the auxiliary belt had snapped and jammed itself in the pulley causing the damage. They are to take the head of to see what damage has been caused, he is talking about a bill of upto £1500.
As this car has been serviced from new, by the same main dealer, would any of you think they may be at fault in not changing the auxiliary belt at the same time as the cam belt.
JC THACKRAY

When you say the "auxiliary belt" I take it that you are talking about the alternator belt or as it's usually known - the fan belt. It's not unknown for this to break and cause all sorts of trouble. Unfortunately, I don't think that you will have any joy in trying to blame this on the garage. However, a good garage would have inspected it and told you if it needed replacing. Mind you it's not easy to see and it might have looked OK from a quick inspection.

You say that you have a 1998 Steptronic - I didn't think that this model came out until 2000 - curious.
David Clelland

Sorry it is a 2001 model. The garage has come back to me to say now that the head is off the damage is worse than they thought. All 16 valves damaged and the cam shaft snapped. The quotation is now £2700 for a rebuild. I am not sure whether that includes vat, I hope so.
Looking at autotrader the car is only worth about £2500, probably not worth repairing.
JC THACKRAY

At that sort of money you'd be better off sourcing a second hand engine.
David Clelland

Normally the alternator belt is only changed when worn, but if the risk of serious damage is so great, perhaps there's a case for changing all belts at the the 5 year/50k service?

Chris
Chris

I find it difficult to determine a failure sequence with this damage, ie.What failed first ?? ie.the failure of an alternator belt is very unlikely to break a camshaft but then if the shaft failed first then it would stop turning and only a few valves would be bent.
Do you know an expert, or is there a volunteer on the Forum in your area who can look at the bits ??
The alternator belt is removed for a cambelt change so why not replace it ??
Geoff F.
Geoff Farthing

It's happened a few times, the frayed end of the snapped alternator belt getting pulled into the timing belt and making it jump. It sounds to have properly toasted that engine, if the pistons have battered the valves with enough force to snap the camshaft then I'd not be confident there aren't stress fractures in the pistons/rods/crank, therefore I agree with Dave - ditch it immediately and source a secondhand unit. you'll save a lot of money and provided you get an identical spec engine it's a quicker solution too.

I've had an auxiliary belt snap only a short time after a visual inspection which didn't find any evidence of degradation, so it is definitely a good idea to renew the belt even if it looks fine. Dealers tend to only replace bits that can be justified if necessary by producing the old part with wear/damage evident. Blame our increasingly litigious society 8-(
Mike

Agreed - get another engine. 500 quid for an MPi engine in good nick is certainly possible - to which you'll need to add fitting, but we'd be looking at a 2 hour job, so not too expensive :o)
Rob Bell

This thread was discussed between 05/09/2008 and 12/09/2008

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