How often should you change your alternator belt?

[Manuel]

I haven't changed my alternator belt in over five years and over 1000 hours of engine running. It still looks in good nick and there is never much dust from the belt in that area. It was one of the most expensive belts you can buy, made in the USA and I keep a spare. On my engine the belt drives the fresh water pump and the alternator.

Do I say this is a good belt, a proven belt, an a belt to keep or do I say this is an old belt and it must be changed? I check it and tension it on every engine inspection. Would I see problems before it breaks?

Edit: What do the long distance truckers do?

 

[PeterGibbs]

The time to get your spare out is when the edges of the belt start to fray, there are fibrers, not just a little dust around the pulleys. Mine has done over 3k hours over 10 years, yours is a youngster!

It really does help to keep the tension on the belt correct - slack tension and years are whipped off the life! And I assume your alignment is correct...it can drift if the alternator is not quite in line.

PWG

 

[Manuel]

That is very reassuring, thank you! It seems silly to change perfectly good stuff for the sake of it.

 

[Ludd]

I haven't changed my alternator belt in over five years and over 1000 hours of engine running. It still looks in good nick and there is never much dust from the belt in that area. It was one of the most expensive belts you can buy, made in the USA and I keep a spare. On my engine the belt drives the fresh water pump and the alternator.

Do I say this is a good belt, a proven belt, an a belt to keep or do I say this is an old belt and it must be changed? I check it and tension it on every engine inspection. Would I see problems before it breaks?

Edit: What do the long distance truckers do?

As a (thankfully) ex long distance driver(HATE the word trucker,I would point out that a belt on a lorry is run under constantly changing loads/speeds and is MUCH harder worked than in a marine application: even then they last for one heck of along time!!

 

[bobgoode]

Guess it's a balance of cost to change versus inconvenience when it breaks.

Mine is changed each year as part of the service but the old ones show little or no wear in 100...200 hours. I guess I could keep them way way longer and save some pennies.

 

[Billjratt]

As mentioned above, there will be evidence of stress before a well set up belt gives out, however, if it was kinked or forced over a tight pulley during installation, it may suddenly fail. If it's run stress free for a season let it carry on with the good work....

 

[cliff]

Depends also on what engine you have. An engine that uses the belt to drive a coolant pump as well as the alternator should be changed if there is any doubt over its "health" whereas on a pukka marine engine, such as a Bukh, the loss of a belt is of no real immediate problem - the engine will continue to run quite happily regardless - no threat of overheating. OK so you will not be charging the battery banks and may need to conserve electric power until you get round to replacing the belt.

 

[gordmac]

My experience is that when it is done it won't hold it's tension. Many years ago I put a new fan belt on my car as a precaution, it lasted about 60 miles and broke, went into the cam belt and did a fair bit of damage. If it ain't broke, don't mend it!

 

[oldharry]

Many makers recommend replacing any stressed rubber component every five years regardless of wear or use. This includes belts and tyres, on the basis that the rubber will have begun to deteriorate at that age regardless of level of use

This does not mean they may not last a great deal longer. My 12 yr old Renault Van was still running on the original cambelt, and which appeared absolutely fine after only 30k miles. I wondered what all the fuss was about when I took it off, but replaced it anyway.

An indicator of advancing wear on a Vee belt is how far down the Vee the belt is when it is set up. At or near the bottom, it is quite badly worn and needs replacing. Ideally the outer face of the belt should run more or less in line with the outer edge of the pulley it is running in.

The inside face of a plain belt, or the bottom corners of the teeth where they join the main body of the belt, should be stressed backwards to see if there is any sign of cracking. If there is, the belt is on its way out.

 

[TonyS]

Mine failed going north in the Alderney Race about 4 miles before Cap de La Hague. There was wind to just about sail but I was really pleased to find the tools and have the replacement in place and running inside 10 mins - just before it started to get really bumpy. That was 600 hours on a VP 2030 with a Sterling regulator.

 

[pcatterall]

At least once!! What I mean is that if you do it once, you are sure that there are no snags or special ( cut down etc) spanners that you may need and that the spare is really the right size. Keep the trusty old one if its ok.
Hopefully when you need to do it in a hurry there will be nothing to go wrong!!