Air con pump – noisy

[CanhamCan]

The air con pump is noisy on my ’02 110hdi 406 and the car ‘shudders’ to a halt when the engine is switched off. The noise disappears above tickover and when the engine is warmed up and strangely seems to be less when the air-con is switched on.

Am I looking at getting the pump replaced or is there something I can have a look at first?

Thanks in advance for any help,
Chris.

[Welly]

There's a few things to check here, firstly if the a/c pump is noisy (sort of grumbly) then the system is low on gas - the compressor is 'scavenging' and it won't be long before it's shut off by the ECU to save wear. You will hear a noise which will rise and fall in line with engine revs, and stop once you turn off the a/c.

A metallic clicking/tapping sound from the same area (especially on cold starts) is normally the bottom pulley failing. This can go away when warmed up but eventually (and quite quickly) it will turn nasty in that the noise will be so bad you won't feel like driving it far. Also look for a brownish dust around the bottom pulley area and look for shards of shiny metal flakes etc - all signs that the pulley is giving up.

The engine shuddering on shut-down is most likely the rear lower engine mount (there's lots on here about that) but basically they are rubbish and let the engine move far too much - eventually fracturing the exhaust flexi and CAT section so turns sour very quickly (mine even tore through the IC hose at the same time).

[leestudd30]

My picasso shudders when turned off as well. Is it an expensive job labour wise replacing the mount, seen a new mount on ebay for £13.

[CanhamCan]

There's a few things to check here, firstly if the a/c pump is noisy (sort of grumbly) then the system is low on gas - the compressor is 'scavenging' and it won't be long before it's shut off by the ECU to save wear. You will hear a noise which will rise and fall in line with engine revs, and stop once you turn off the a/c.

A metallic clicking/tapping sound from the same area (especially on cold starts) is normally the bottom pulley failing. This can go away when warmed up but eventually (and quite quickly) it will turn nasty in that the noise will be so bad you won't feel like driving it far. Also look for a brownish dust around the bottom pulley area and look for shards of shiny metal flakes etc - all signs that the pulley is giving up.

The engine shuddering on shut-down is most likely the rear lower engine mount (there's lots on here about that) but basically they are rubbish and let the engine move far too much - eventually fracturing the exhaust flexi and CAT section so turns sour very quickly (mine even tore through the IC hose at the same time).

Thanks Welly, The bottom (composite) pully failed last year and I changed it along with the aux belt and tensioner then, will check the gas though (made up a DIY stethoscope to check where the noise was coming from.) Better check out the rear lower engine mount before things get expensive, something to do at the weekend - ho-hum.

[jonsowman]

Could be the air con clutch? Mine rattles sometimes when off but shuts up when the air con is engaged.

[grasmere59]

Have you checked the alternator clutch pulley,that can give strange effects when it seizes up.

[CanhamCan]

Could be the air con clutch? Mine rattles sometimes when off but shuts up when the air con is engaged.

It certainly quietens down when the air con is on.

[CanhamCan]

Have you checked the alternator clutch pulley,that can give strange effects when it seizes up.

Had a listen to all the pulleys through my homemade stethoscope - copper pipe and hose pipe - and apart from the air con pump everything was nice and quiet. Amazing what you can listen to with such a simple tool, spent a good 20 mins listening to all sorts of stuff whiring around (simple tool for a simple tool )

[gumby6371]

Lee,

To answer your question about the lower mount bush it can be done without removing the mount but it's fiddly, you need to cut out the old mount with various pointy and sharp objects then 'persuade' the new bush in with some sort of improvised press.
I did see a vid on you tube where a guy had made a small puller out of an old scissor jack and various sized sockets which could do the job but you might want to put the new bush in the freezer over night and use plenty of grease to make the job easier.

Other than that it's drive shaft off and run the whole thing down to a friendly garage with a press.

[mjb]

To answer your question about the lower mount bush it can be done without removing the mount but it's fiddly, you need to cut out the old mount with various pointy and sharp objects then 'persuade' the new bush in with some sort of improvised press.
I did see a vid on you tube where a guy had made a small puller out of an old scissor jack and various sized sockets which could do the job but you might want to put the new bush in the freezer over night and use plenty of grease to make the job easier.

I did some calculations before changing the mrs' bottom mount, and worked out that freezing it from 20c ambient to -30c only gives around 2mm shrinkage on the circumference, which is around 0.05mm shrinkage on the diameter - really not worth it for this job (not to mention the steel returns to ambient temperature *very* quickly...)

To get the old one out, I slapped the bracket in a vice, cut the rubber, cut the steel band, then attacked the (corroded in place) band with a hammer and screwdriver until I could rip it out. To get the new one in, I smeared the bracket and mount with washing up liquid, then just pressed it in with the vice which was a hell of a lot easier than the first time I tried the job using nuts, bolts, and scrap wood.

Unless you've already got a tried-and-tested portable botch-press rigged up, I can't see it being quicker or easier to do it in situ

As an aside, the bi-product of removing the driveshaft is you need to drain and re-fill the gearbox oil. The gearchange action on the Mrs' car is vastly improved as a result!