CRD - Rattling sound at idle only when AC is on

[mike_nofx]

When its idling with AC off it all sounds normal, as soon as the AC is turned on there is a noisy rattle coming from somewhere near the engine. I'm yet to pinpoint it. I'm hoping someone can tell me if this is normal, or if its a common issue?

I know my description is quite vague, I could get a recording of it if necessary with AC on and off to hear the difference.

Thanks for any advice

[samft]

I believe the electric fan comes on when the AC is turned on.

Mine squeeked instead of rattled for a while when i switched on AC

[Von Depner]

Willing to bet you need a new serpentine belt tensioner. I had a similar issue and replaced mine and all noise gone. Contact MidnightMod's for a new one he is by far the cheapest in Oz. $375. for kit tensioner and new belt.

[MidnightMods]

Was about to say its most likely the serpentine tensioner, how many km's on it?

When the car is running, get someone to turn the air con on and off, while you stand over the engine bay and watch the serpentine tensioner, its the tensioner on the fan belt on the drivers side, you can see it from other the car as well. If this is moving more then 2-3 mm when air con is on and off then its starting to fail. Common problem as the parts life span is around 70,000-110,000km in most cases

[MRGC]

Agree with midnightmods.


, [____],
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[mike_nofx]

Ah ok thanks very much guys. Will check the tensioner.
Has 167k km

[RLT]

Originally Posted by MidnightMods

Was about to say its most likely the serpentine tensioner, how many km's on it?

When the car is running, get someone to turn the air con on and off, while you stand over the engine bay and watch the serpentine tensioner, its the tensioner on the fan belt on the drivers side, you can see it from other the car as well. If this is moving more then 2-3 mm when air con is on and off then its starting to fail. Common problem as the parts life span is around 70,000-110,000km in most cases

Yeah mine went about 65,000 miles (104,000Km)
Mechanic who replaced the Timing belt & water pump (VM parts) said that they can go anytime and it did 2000 miles later.