cam belt tensioner

Hi all, bit of advice for a mechanical novice please!

I've just serviced and MOT'd the supe and it failed on the dreaded emissions. After doing a diagnostic they sorted out the connections on the lambda sensor which sorted it right out.

However, the mechanic who did it said he spotted a mark on the cam belt (which was changed a year ago at about 55,000miles) that suggested the tensioner wasn't quite right and might not have been changed with the belt.

Should it be usual for a garage to change the tensioner as a matter of course when doing the cam belt? I didn't ask them to change it (as I didn't know anything about it) and would like to know if I can go over and throw a strop at them or not!

As I understand it it's pretty major if the tensioner breaks. Therefore should I get it changed if it looks like a problem now?

the mechanic who did it said he spotted a mark on the cam belt (which was changed a year ago at about 55,000miles) that suggested the tensioner wasn't quite right

Should it be usual for a garage to change the tensioner as a matter of course when doing the cam belt?

As I understand it it's pretty major if the tensioner breaks.

Therefore should I get it changed if it looks like a problem now?

It depends on what he means by a "mark". The spine of the belt gets marked after a few minutes normal running due to the way it passes over certain pulleys.

Why was he in around the timing belt anyway when the problem was with the O2 sensor(s), am I missing something?

Its good practice to change the tensioner at the belt change but not all fitters will do it without it being requested.

Many thanks for the advice!

Why was he in around the timing belt anyway when the problem was with the O2 sensor(s), am I missing something?

He was looking at the belt as wanted to check the plugs so the cover came off and he saw the belt too. Basically he was investigating all the options for it running too rich.

After the diagnostic was run it pointed to the O2 sensor reading incorrectly so he sorted out the connections which solved the issue! Briliant - no big bill for me!!

Re the cam belt tensioner he did say that it prob wont be a prob as it's not making any noises but to keep an eye on it. To be honest I'll prob get it changed (and a new belt too I guess) as I don't want it letting go and giving me a hhuuuuugggeee bill!

Re the cam belt tensioner he did say that it prob wont be a prob as it's not making any noises but to keep an eye on it. To be honest I'll prob get it changed (and a new belt too I guess) as I don't want it letting go and giving me a hhuuuuugggeee bill!

If you're doing that I'd also advise to look at your crank pulley whilst you're at it. The tensioner normally starts squeaking before it lets go and doesn't fail in a catastrophic manner (iirc) that the crank pulley can do if the outer ring separates at speed (can damage belt, radiator, fan etc)

IIRC tensioner is about £120, pulley about £170-180?

Never heard of anyone having a catastrophic incident or major damage from the tensioner failing, but if it does really slack yes it could be an issue.

Sorry, you're talking about cam belt? I thought you were talking about aux belt! Ignore me if you're talking about cam belt.

EDIT: BTW your engine is non collisional. A cam belt breaking will not destroy the engine, just normally means you'll need a new cam belt and get the timing sorted. I think the cam belt is actually cheaper than the aux belt too.

Re the cam belt tensioner he did say that it prob wont be a prob as it's not making any noises but to keep an eye on it. To be honest I'll prob get it changed (and a new belt too I guess) as I don't want it letting go and giving me a hhuuuuugggeee bill!

I can't see how you can 'keep an eye' on the cam belt tensioner, its not exactly easy to see!? I would've had it changed at the same time as the cam belt was.