A/c Compressor Fail

[Ben565]

Hi all,

On a recent trip to Scotland I pulled over at the services and saw what looked like steam coming from the front grille, no warning lights on the dash and it wasnt overheating so I assumed it was just condensation from the A/C

A day or so later when overtaking a nasty rattling sound came from the engine bay at around 4,000 rpm. Didnt sound good but the car was driving fine at lower revs.

I headed straight for the nearest Toyota dealer, their technician came out revved the engine up and replicated the rattling sound. He immidiatly switched the engine off, got out and said, thats your A/C compressor gone for a game of soldiers. I asked if this would have anything to do with the steam coming from the front grille. He bent down to take a look and said, Ohh yes! .... Big hole in the radiator.

Apparently the Avensis has a multi layered radiator? anyway a stone has gone through the A/C part, causing the gas to escape, running the system dry. Because of course I had been driving around with the climate control on, totally unaware all the gas was happily evaporating away.

The technician advised me to turn the climate control off and I should be fine to continue driving. I checked in with my local dealership when I got back who seemed to think replacing the Rad and regassing would fix the problem. This was their initial asessment but based on what I told them about the rattling sound they couldnt guarantee the compressor wasnt also damaged. They quoted £2,000 to repair.

I contacted a local A/C specialist who told me they could recon the compressor, and that I would also need a new rad, drier unit, the system needed flushing of any contaminates, and then regassing. £750

Thing is though, shouldnt the A/C system have a low pressure switch that disables the compressor if the gas run low, thus preventing any damage?

why would it make that nasty rattling sound at high revs if it was disabled by the low pressure switch?

Can I get away with just replacing the rad and regassing?

[Joseph M.]

Hi Ben,

Unlike many other cars/models, the Avensis AC compressor is not clutchable i.e. it turns with the engine all the time whether the AC is on or off. The compressor has a plastic coupling in its drive mechanism which breaks should the compressor get jammed so that the compressor gets disengaged from the pulley and the engine can still turn. The compressor gets lubricated by the gas itself which has an oil content in it. If the gas escapes the compressor may get starved of oil leading to damage. What you can try is remove the pulley V-belt and turn the compressor pulley, see if it's still engaged and if yes whether you feel any noticeable resistance or scraping / hear noises. Perhaps other members have other ideas??

[Ben565]

Thanks Joseph

Judging by the length of time I was driving it with the climate control on, and the noise it was making I would suspect the compressor has gone.

[t-spiritpete]

Thanks Joseph

Judging by the length of time I was driving it with the climate control on, and the noise it was making I would suspect the compressor has gone.

You could always just fit a belt from an Avensis without aircon and bypass the compressor altogether and you wont need to change the damaged radiator either, it all depends on your personal requirements. These belts are readily available from Toyota or factors.

Pete.

[Ben565]

It's running fine at the moment, no noises or anything so long as I don't put the A/C on. Just wondering if there was a chance of a low pressure switch having saved the compressor but it appears not.

[Druid Boy]

Ah, saving the compressor would mean not selling replacement parts and that, boys and girls, is where the profits are. Hence no switch.

Too cynical for a Friday night?

Oh well.

[Ben565]

Diesel engines chuck out loads of sooty black gunk right? how about we fit this valve, that recirculates that crappy dirty sooty sht back into the intake. That'll make it run bad so it produces even more dirty black stuff which, gets sucked back into the intake, which makes it even worse... eventually it'll clog the whole works up so much it blows the head gasket. Just to be sure though we won't include the cleaning of this valve in any kind of service schedule. What a jolly jape that will be on our poor unsuspecting customers. Hey! we could even fit them a new engine and still not bother to clean the tubes out, thus blowing the new motor in record time.

Moi cynical? :)

Seriously tho, in what boardroom meeting did they all sit down and think that was a good idea?

[Druid Boy]

Ah, I used to call these ideas "SOGI's". Senior Officers' Good Ideas. Basically they find out about some great bit of technology (or an idea), they like it, their friends like it, they only consider it in isolation rather than considering the whole system and they implement it basking in the glory of their success. Think transport industry boffins saving the planet by reducing exhaust emissions on motorway journeys rather than investing in city centre infrastructure schemes to keep traffic moving or actually get the public transport system working. Mad stuff like monorails alongside dual carriageways, so you can park your car and actually get to where you need to on public transport.

Hmm, I think I need to drink more.