Cambelt EXPLOSION

goatfertility

Do cambelts go boom without warning? What I mean, is would it be possible to do a visual inspection on and old belt. For it to look okay, but due to age just suddenly give way?

Or do cambelts that are goners usually look like goners before they go pop.

Strider590

Cambelts are normally taken out by a worn tensioner, roller or water pump.
The cambelt itself is rarely the source of failure.

Unfortunately when they need changing a lot of people go cheap and just change the belt (which I why I always fit a full kit when I buy a used vehicle).

I have in the past had a full belt kit changed at just 10'000 miles, because I could hear the tensioner wasn't happy.

Tensioners, water pumps and rollers often get rather noisy prior to failure, a bit like a PC fan when it's bearings are worn and it sits there screeching.
Tensioners are by far the most common failure in that system, these will give a grinding or erratic ticking noise (not to be mistaken for the rhythmic ticking of the valve train).

If there is visible oil/water contamination on the cambelt components, this needs to be rectified ASAP, to stop the belt slipping.

Lastly, make sure your looking at the cambelt (this is normally under a plastic cover), the auxilleries (used to be fan) belt drives the alternator, aircon pump, power steering pump and is usually easily visible.

chrisw

It's not usually that dramatic for the damage it does. Mine snapped prematurely at 50mph and the only giveaway was the engine cut out with a gentle metallic tinkling sound as the pistons mashed the valves.

Sometimes you can see the rubber starting to crack around the bottom of the teeth and if you're lucky it will strip a couple of teeth rather than snap.

But generally, it would be foolish to rely on a visual inspection.

Igol

I had a belt go with little warning on an old Rover.
Only indication that it was stripping teeth off the belt was the odd judder like a misfire the day before on a 50 mile commute, next morning I managed to do 25 miles with no issues then it just stopped when the belt gave way.
Car dead and scrapped, since then I swap them before they're due along with the tensioners.
Very much like oil, belts are cheap engines are expensive.

AdrianC

I had a belt go the week before Easter.

It'd been fitted this time last year, about 12k miles ago.
The car was fine on Friday. When SWMBO went outside and started it up on Saturday, she turned it straight off and came back in. "It doesn't sound right". No kidding. It's a diesel, and it was LOUD. So loud that neighbours from several doors away asked what the noise was. Turned out to have jumped a tooth on the crank sprocket - no idea why. The suspicion was the tensioner - it was a full kit from an OEM quality brand.

tedted

what diesel is that then

AdrianC

tedted wrote: »

what diesel is that then

XUD 1.9 turbo, in a ZX.

tedted

when these hit they tend to crack the camshaft caps and break the camshaft ,it seems you have been lucky and maybe just cracked the caps

LandyAndy

AdrianC wrote: »

XUD 1.9 turbo, in a ZX.

I had that engine in a 405. Not exactly the quietest at the best of times. It did 245000 miles without trouble though.

AdrianC

tedted wrote: »

when these hit they tend to crack the camshaft caps and break the camshaft ,it seems you have been lucky and maybe just cracked the caps

Fortunately, it only seems to have jumped one tooth, and nothing went pushy-shovey inside. The belt's been redone, and it's done 5-600 miles since.