alternator belts tension etc

[Gripped]

Replaced 3 belts (the twin alternator belts and the air con).

Seemed to go ok - much easier to do from underneath with the undertray removed, as you can see all the gubbins.

But I do now have a whine which increases with revs. Fairly sure it's the alternator belts. I've loosened off the tension, but it still does it. Any ideas?

Also, what is the rule of thumb for belt tension? Twist the belt 90 degrees? or push it down a certain amount?

Thanks in advance !

[knpenny]

does the sound change when you activate the ac, another idea is disconect your alt belts, with engine off get a long screwdriver and put the metal end on the ac compressor:pump put your ear on the handle and spin the pulley and listen for an uneven grinding noise. just encountered a very loud whine noise that you described at my work and it turned out to be ac compressor.
hope this helps

[Gripped]

Hiya - yes I've fiddled with the a/c and loosened off the tension and switched a/c on and off, but doesn't make much difference.

I might have to totally remove a/c belt to be sure, but I'm fairly sure it's the alternator belts.

[knpenny]

suppose the best thing to try is take off ac belt first start it and see if it still makes noise switch off as quickly as possible and then repeat with alt belt if need be that should give you the best indication.

[Gripped]

ta

Any ideas on the tension ? I don't want to do too loose or tight.

[knpenny]

for the ac belt take tension between ac compressor and idle pulley with 10kg force applied if new 7.3-8.5mm if reusing 8.5-9.7mm
for alt belt between oil pump and crank 10kg force applied for new belt 7-7.5mm and reusing 7.5-8.3mm

good luck, to be honest most of the time i use the 90* rule and that usually seems to be fine but in reallity you should never twist a belt and you should use a proper tension guage, Hope this helps

[Gripped]

That does indeed help.

Thanks loads. I've got my overalls on, and the bongo is on the ramps !

At least it's not raining. Yet.

[knpenny]

wish it was the same here in france so i can get the cam belt and both aux belts along with coolant and thermostat whilst fitting coolant alarm done but its been crap.
have fun dude

[Northern Bongolow]

its good practice to clean the V of the pulleys when swapping the belts.
an older V belt is narrower so sits lower in the V, when you put new belts on the belt sits higher in the pulley on the dirty /rusty bit that may not have been used in a while.

[Gripped]

All sorted I think.

Just one question, is there a torque setting for the 17mm bolt for the air con tensioner pulley?

Ta !

[knpenny]

32-46 nm

[Gripped]

Thanks!

I was considering doing it to "FT" but I thought that might be a bit too much for a 17mm nut.