Air con makes car rattle

[Brian L]

Next thing to sort out is a rattle from the exhaust that happens when the air con is on, the air con pump turns off and on when switched on, there is a slight rattle from the pump like the bearing is going but anyone any ideas why the engine starts to vibrate more causing the exhaust to go psycho, does the air con need regassed or the the pump replaced?

Any ideas much appreciated

 

[Ben Stratford]

Perhaps the rpm's drop slightly when turned on causing an increase in vibration due to resonance or something?

 

[clivehorridge]

I have (and I think most will have) on the 80 series, an idle-up so that as the pump kicks in, the revs will be lifted a 100 rpm or so to compensate for the extra load.

Presuming this only happens when idling, not when you're driving?

 

[silvercruiser]

Does it sound like this?

 

[silvercruiser]

I have watched my aircon closely today (thanks Frank) and when engaged i can see the pulley start to wobble on the compressor (not much wobble but just enough to see by eye) and that is enough to make the engine feel a bit lumpy. so maybe yours is the same. Its worth a look.

 

[Chris]

Was that the pump Joe or the tensioner? It's a cheap little bearing in there and if over tensioned doesn't last long. Bad news if it's the pump. You can get replacements quite cheaply. Someone posted a link a while back. I need one too. My overland 80 pump is leaking badly.

 

[silvercruiser]

Its the Pump Chris. all is fine until the magnetic clutch pulls in and then you can see the wobble so the thrust bearing in the pump is on its way out. i did think about replacing the bearing but the whole lot needs to be split then i need new seal etc, so im looking at a new pump for ease really.
on my lc120 you cant over tension it as its sprung loaded.

 

[Brian L]

I'am getting this noise a bit but the exhaust has starting rattling as well, sounds like there's a stone in it(maybe there is!!) will have to get under and get a look.... could part of the reason be that there is a leak in the system and when there isn't much gas left the system starts to struggle as it has nothing to pump around thus creating vibration, just a thought, going to get an aircon service soon

 

[Brian L]

well I found the problem, it was a split in the exhaust in the tail pipe, just where it bends over the top of the rear axle, it split that much on opposite sides they rattled together, new tail pipe I reckon!!