Do I need to change auxiliary belt tensioner and idlers? - Alfa Romeo Forum
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(Post Link) post #1 of 7 Old 17-06-19 Thread Starter
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Do I need to change auxiliary belt tensioner and idlers?

I'm doing the timing belt on my 166. It's a 2000 car but it only has 16,000 miles on the clock. Despite the car being driven weekly until 2016 neither of the belts have ever been changed. The car has been parked indoors all it's life so there is no rust anywhere on it. I'm just wondering if I need to change the aux belt only or do I need to change the tensioner and idlers too.

And yes that mileage is correct. 16,319 to be precise.
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I would absolutely change it all.
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Change them.

If they fail they will at least cause a breakdown. There is also a slim chance that a damaged belt could find its way behind the pulley and into the cambelt area which could be catastrophic for the engine.

And you already have it bits to do the cambelt so it won't take any more effort to fit new parts.
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I don`t think there is any need to change the idler and tensioners IF the bearings are alright. It depends however on your experience as to whether you can correctly ascertain that the bearings are still ok . They are sealed so they should still have all the original grease in them but check visually to see if the seals are in fact still ok. The material the seals are made of normally doesn`t deteriorate and as the car has gone through obviously a relatively small number of cycles and well under the change cycle use, merely need a checkover in my opinion as an ex Euro garage proprietor. If I still owned my workshop however and you came in as a customer, out of safety I would change ALL belts , tensioners, idlers and water pump. It is only on my own vehicle that I would reuse , if ok and properly checked.- a considered risk. That cambelt though needs changing, just as a safety precaution and if the car hasn`t had much use I wouldn`t trust the water pump, they do pack up through lack of use as well as a lot of use. They can also give way without audible warning as I found to my cost in a little used re km`s TS of mine.
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All of it. I would change all. Considering how much they are passed their time. Materials deteriorate, grease and lubricants in bearings age and oxidize, losing their protective and lubrication ability.
You'd be doing yourself a favor as well; keeping that side of the engine free of worry for the next three years.
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As long as no grease is leaking from the auxiliary pulleys, they should be ok as I've yet to see an auxiliary pulley become worn with less than 100k mileage.

Changing the auxiliary belt is wise. The properties of the rubber have probably changed and cleaning the pulleys with a wire brush to remove any rubber particles helps minimise the chances of a fluttering noise when the engine is cold.

You didn't say what engine you have but changing the timing belt, coolant pump and all timing belt pulleys seems wise.

If it is a 2.0TS, I'd have a close look at the balance belt pulleys and fit a new balance belt.

If it is a 2.5 V6, the coolant pump impeller is probably plastic.
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(Post Link) post #7 of 7 Old 02-07-19 Thread Starter
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It's a 2.5 V6. We changed the timing belt including pulleys although the bearings felt absolutely perfect in the ones we took out. I'm sure they would have been fine for the handful of miles it will complete over the next 5 years but for the sake of it and some peace of mind, there was no point keeping them. We also did the water pump and changed it for a metal impeller one.

We changed the auxiliary belt only as there was no roughness at all in the pulleys and they have done next to nothing. The car spent it's entire life indoors in an insulated garage so it would be very unusual for them to be rough. The aux belt was after deteriorating alright so glad that we changed that out.

Running nicely now.
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auxiliary , belt , change , idlers , tensioner

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