I changed the auxiliary belt recently as a precaution but have noticed a bit of movement on the idler pulley. Does anyone have a pulley available which could be examined for the bearing size please?.,…(usually stamped on the bearing casing).
Given the price of bearings against the price of a pulley it must be worth replacement musn’t it?
I’d imagine a bearing being cheaper than the whole pulley.
You don’t mention which model you have.
2006 NC 2.0 L
Pretty sure all nc models use same idler pulley.
https://www.mx5parts.co.uk/alternator-belt-idler-pulley-mk3-35-p-2297.html
Make sure it is the bearing that has gone.
A lot of the earlier MK3 cars had issue with the plastic bearing housing on the idler pulley. Bearing fine but wear/collapse of the housing causing excess movement and noise.
Suggest you take a closer look at yours as may require the complete unit.
Thank you… I wasn’t aware of that possible issue.
Yes, something like this has happened with other makes of car as well. My old Vectra had a recall because of the possibility of the plastic rollers in the cambelt idlers separating from their bearings, and they reduced the recommended mileage and time between changes, partly because of this.
Remember also that some plastics, especially nylon, can absorb oil and other solvents and swell up, and in the case of the idlers maybe enough to crack the roller off the hub (as happened with some of our very expensive industrial film equipment back in the 1970s and 1980s).