Timing belt broke after 50k miles?!

Have a 2000 Mazda Protege ES with 150k on it.

Have taken meticulous care of it and had the timing belt changed at 100k by Mazda dealer I bought the vehicle new from.

Friday night it stopped dead in its tracks and it sounds like the current timing belt has broken!!

Is there any kind of warranty on timing belts? is it

50k failure out of ordinary?1
Reply to
me
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That's a question to take up with the dealer who did the work. The first thing for the dealer to determine is whether the timing belt broke.

Reply to
John S.

It seems inappropriate to bitch about a broken timing belt when you haven't properly disgnosed the problem yet.

Reply to
zzyzzx

It's being diagnosed as we speak....and who says I was "bitching"?

Lets just assume it is the timing belt..... so is 50k a bit short on its life?

Reply to
me

Depends on the car. On the '82 Ford Escort it would have been a miracle if you could have got 50k on a timing belt.

--scott

Reply to
Scott Dorsey

The belt is generally guaranteed for the change interval. All the other stuff that broke when the belt broke is not. I don't know your vehicle so I can't speak with authority but the Gates web site shows the belt should be changed every 60k (non california) and the engine is not an interference engine so you won't have bent valves to deal with.

Some water pumps are driven off the timing belt and there is almost always a tensioner or two in there that can fail so until you have someone pull it apart there isn't any way to know what happened.

Steve B.

Reply to
Steve B.

Whether someone considers it to be "a bit short on it's life" is irrelevant.

Again, have you determined that this is a broken timing belt. And have asked the dealer how long parts that they install are warranted for. Those are questions that you will not get straight answers to on an internet discussion forum.

Reply to
John S.

You certainly wont, and you wont get them from some dealerships EITHER.

50 k (miles, I assume) is a bit less than one would expect. You are darn lucky that, if this turns out to be a snapped belt, you dont have an interference engine.
Reply to
HLS

You work with strange dealerships. The legitimate dealerships I deal with provide a very legible disclosure of how long replacement parts are warranted for. But the real point here is that the original poster should first determine what the problem is. He hasn't determined that the belt broke, but just seems to be fishing for attention.

Reply to
John S.

You work with strange dealerships. The legitimate dealerships I deal with provide a very legible disclosure of how long replacement parts are warranted for. But the real point here is that the original poster should first determine what the problem is. He hasn't determined that the belt broke, but just seems to be fishing for attention.

====

First of all, what's an "interference engine"? I've never heard that term before.

Secondly, I'm puzzled by some people's reluctance to answer the OP's question: "Is 50K a short lifetime for a timing belt?". It's immaterial whether he's established whather this is the cause of his problem - and in his followup he even said "Lets just assume it is the timing belt".

I'd say that if the replacement interval for routinely replacing the timing belt is X thousand miles and the replacement belt fails within that time, someone should be held liable - whether it's the manufacturer (defective part), garage who fitted it (defective workmanship) or car maker (incorrect service interval specified).

On a related note, I'd like to know how a garage can examine my fan-belt (well, alternator and power-steering belt) amongst other things at a service, and mark it as "visually checked - OK", and yet the belt breaks one week later... Surely the reason for visually checking a belt is to detect imminent failure *before* it happens, to avoid stranding me in the middle of nowhere late at night, requiring me to be towed home. To add insult to injury, the replaced belt broke one month later because there had been undiagnosed damage to the crankshaft pulley that hadn't been picked up when the belt and idler pulley were replaced :-( The garage reluctantly made a goodwill payment of a mere 20 - less than a tenth of the cost of the belt replacement.

Reply to
Mortimer

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The manufacturer has a specified change interval. The belt itself should last at least that long. The things the belt is turning can fail and take out a perfectly good belt long before it is scheduled to be replaced.

Again, it depends on why the belt failed. If the water pump is driven off the timing belt and fails it will tear up the belt. Same with the tensioner. The cam could even quit turning... Most of the belt manufacturers limit their liability to the cost of the belt.

Belts often look "good" and fail. That is why belts have a prescribed change interval. Yours is a perfect case of "something else failed". In your case the belt probably did look fine, the crankshaft pulley was damaged and chewed hell out of the old belt pretty quickly. The new belt lasted a bit longer just because it was new before the same damaged pulley got it. A damaged crank pulley is a pretty rare thing so the shop didn't notice the damage (on some cars you can hardly even see the crank pulley from above). Crappy situation but it happens.

Steve B.

Reply to
Steve B.

Ah. I'd never heard that term before. I see the difference:

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has diagrams which show how for a non-interference engine, the valves and piston never occupy the same space whereas for an interference engine they overlap though never at the same time! I'd thought that *all* engines were interference type.

Interestingly the belt split lengthways, with only half the width breaking in two. So the belt didn't just fall off into the road and was still there to be examined when I stopped the car. The ridges that engage with the crank, alternator and power steering pulleys had tiny cracks across them every millimetre or so, as if the rubber had perished. It was the idler pulley rather than the crank pulley which was damaged on the first occasion: it looked as if it had shifted sideways on its shaft and scraped against the engine housing.

Mind you, as far as I know, the belt had never previously been changed at a service - and the car had done 120 K miles. I wonder if it should have been replaced every so often.

Yes. When it happened the second time, I'd driven a long way the day before without any problem, then within a mileor so of setting off on a long journey the next day there was a clattering chugging noise (I thought there was a tractor behind me!). This seemed to get worse whenever I came off the power. I limped back home again, with the ignition light occasionally flashing on (a sure sign that the belt had problems) and as I turned into the drive, the noise became much louder. The belt was intact but looked as if it was covered in very viscous oil - my first thought was than the crank pulley bearing had gone and engine oil was leaking out, which would have been expensive! It seems that the viscous black goo was molten rubber from the belt.

A nice little bill - an extra 250 that I hadn't bargained for, on top of the previous bill for this amount when the belt failed the first time.

As a matter of interest, while the belt is off before it is replaced, how easy is it to tell whether the crank pulley is damaged? Would it wobble from side to side on its shaft? I'm assuming that the ridged surface of the pulley was undamaged because surely a garage would spot that as they were fitting the new belt, even if they didn't notice that the pulley was loose on its shaft.

Reply to
Mortimer

In my narrow minded way of thinking no normal street engine should have a timing belt and be of an interference design. Unfortunately nobody asked me when they designed them so I guess my opinion doesn't really matter :-)

The belt probably should have been replaced before that mileage but if the idler pulley failed it wouldn't have mattered... It would eat the new belt too. The ridges can be cracked and the belt still be good. If any of the ridges come off or you see wear anywhere else on the belt it needs to go. Usually a tensioner will make noise before it fails but not always.

It depends on how the crank pulley failed. On most cars that I have dealt with the crank pulley is bolted very very well to the crank shaft A failure of that pulley is pretty dang rare though the harmonic balance is behind it / part of it on some cars and those do fail more often Do you know what piece of the pulley actually broke? On lots of cars you can just see / feel enough of the crank pulley from the top to loop the new belt around it so I don't know how easy it would have been to spot the problem on yours before it happened.

Steve B.

Reply to
Steve B.

Ah, so it's acceptible to have a belt where the longitudinal ridges have cracks at closely-spaced intervals all the way round the belt? OK. It looked as if it was badly perished, but maybe it was still serviceable.

Unfortunately I didn't get to see the crank pulley after it had been removed. While it was in situ, most of it was hidden by the belt, in a very narrow gap between the engine block and the body of the car. There wasn't enough space for me to get my arm in to feel down to the bottom of the engine to reach the crank pulley.

When the engine was running, when I first looked after I got the car home, the pulley appeared to be wobbling side-to-side on its shaft instead of running true to the shaft as it does now.

Reply to
Mortimer

Given the limited amount of information the original poster knows about his car it is literally impossible for anyone to say whether 50k miles or 50 miles is a reasonable life. We do not know what the recommended change level is. Nor do we know whether another component failed and took out the belt. And finally, and most importantly we do not even know if the belt is broken. The OP doesn't know either.

Reply to
John S.

Ok thanks for that info. I didn't "think" it was an interference engine.... but wasn't 100 percent sure. Phew glad it isn't!!

It is a 2000 Mazda Protege ES car

True....should know more tomorrow after mechanic has diagnoses it.... but even he thought it was the timing belt

Reply to
me

I hope that turns out to be all it is!! Please let us know after you get it fixed.. I'm very interested to know if something broke the belt or if it was just a bad belt.

Steve B,

Reply to
Steve B.

Here's a decent guide with pictures:

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Steve B.

Reply to
Steve B.

Thanks for that. My belt was like the "acceptible" picture at the top right of the first page, though with even more frequent cracks.

So it looks as if the belt itself was OK and it was a pulley that destroyed the belt.

Reply to
Mortimer

It was the belt tensioner

Apparently it bound up or something causing the belt to jump a tooth.

The mechanic replaced everything including the belt even tho he said timing belt didn't look too bad. I agreed abt changing the timing belt as well since he might as well with the engine all apart and the belt having 50k on it.

Thank God it wasn't an interference engine!

Reply to
me

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