air con compressor not working...options?

[bigbird]

My 156 S/W 2.4 JTD air con problem has been narrowed down to a malfunctioning compressor, which has been estimatd at £400 plus VAT plus fitting and regassing, so probably £600 or thereabouts. Ouch. There's still an outside chance that it's electrical, and one more examination at the auto electrician's to see if that's the case, but I'm not holding out much hope.

Does anyone have much experience in this area? I'm wondering whether, to save pennies, it's worthwhile trying to source a compressor from a breakers, or is this the kind of part that's likely to be fairly goosed if it's 2nd hand?

My garage said that when they checked for parts, there were 6 different part numbers for different compressors relating to the 156, so it might be hard to narrow down which one is right for my 2004 2.4JTD. Is that true, or is there some way to identify for sure for the purposes of sourcing parts from breakers?

Any recommendations?

Cheers

Iain

[fg53ume]

have you had it regassed? if there empty the compressor will not operate.

could you not put power directly to the plug on compressor and see if the electro magnet works?

[bigbird]

I've had it regassed, and it's not losing any pressure over several weeks. The air con experts said they managed to get thecompressor to kick in once, and tested "most" of the elecrics around it, but their assessment was that the compressor is goosed.

Would a 2nd hand compressor be a good buy (and where's good to find one?), or am I asking for more trouble by pursuuing a used piece of kit like this?

[PETR0LHEAD]

I have a certain amount of personal experience with air con systems due to my time as a jap importer, and only once, (and my own bloomin car!) have i known a totally goosed compressor, and that was leaking so appeared quite obviously as the fault.

exactly as FG suggests, if you put a (heavy Duty) power supply to the compressor positive and earth terminal, straight off the battery in substantial cable, see if the clutch on the end pulls in, and drops out instantly upon connection / disconnection.

this is bypassing the switches, sensors, and relays in the rest of the circuit, so is only testing the compressor clutch itself.

also as FG suggests, the regas.

you may not know to what level it was topped up, but if the chap managed to get it to kick in once, and never again, it sounds typically like the pressure is still low.

the compressor will only throw the clutch in with sufficient pressure and quantity of gas, and if it kicked in whilst being topped up, because you have to do it with the system running with a demand for cold air, then never again, it does sound like the compressor and clutch do work, but then the pressure/quanity level has dropped to below the neccessary to continue to do this once it had moved beyond the comporessor itself.

i know you state you have no leaks, and it has helf pressure over time, but do you know at what pressure?

finally, as i stated at the top, i have only ever known one totally goosed compressor, but, that was on my K reg 300zx, so it already many years older than yours will be, and coming from Japan, very likely had much harder use too, although having said that, most aircon issues tend to arise in this country because folk only think to use it 3 days a year for a blast of cold air on those balmy freak weather days we get.

aircon systems that are sat idle are begging for a breakdown, as the gas also contains lubricant and sealant to preserve the integrity of the systems internals, o'rings, pipework and the compressor itself, and quality gas also contains a visible flourescent to help identify even small external leaks. they should be used all year round.

even if you prove your compressor is Tatered, you can get rebuild kits, new clutch sections etc etc if you search the ole interweb long enough, and they will be precisely for your model and serial number unit, most likely from the states, but still very much cheaper than a new unit, even if you have to pay a local engineer to assist in doing it.

failing that, a replacement used compressor from someone such as Autolusso, or any other reputable breaker should be a good buy and come some sort of guarantee and test that it works, but i don't know what they'll charge for it.

finally, particular to the alfa's, the relays concerned in front of the battery often get tired, and their position often mean the connections get green and far from perfect. I'd swap a relay over for a known one and check that and the connections, and meter for the correct trigger signal from the actual control panel too, i.e. when you hit the air con button, the relay should recieve its trigger to throw over, this can be heard, felt, and measured with a voltmemter, so you can rule out any control panel faults pretty quickly.

good luck

shrew

[bigbird]

A very happy conclusion to my air-con woes...my alfa specialist had originally (after a regas didn't help) suggested a new compressor (expensive!), but when quizzed about the chances of it still being electrrical (cheaper!), he suggested taking it to the local auto-electricians, which I did. They did waffle on about two different models, one which is a control panel and operates from "wave form" signals, and the other via more predictable relaysand 12 volts. He also hypothesised about previous investigations trying to put 12 volts across a compressor which expects a low voltage waveform and blowing it, which wasn't what I wanted to hear.

All investigations done, it turns out to be what the invoice puts as "open circuit in fusebox", which my cynical mind considers as a blown fuse, or maybe I'm being harsh. Now my air-con is blowing nice and cold again, and suspiciously, my 12 volt power from the cigarette lighter is working once again!

So, given that buying, fitting and regassing a new compresor would have been around £600 new, and the "blown fuse" cost me an hour's labour plus VAT at £47, I've gotta be pretty happy, although I'm still thinking how close I was to following advice to spend £600 on a new compressor which wouldn't have solved the problem, and having 3 different attempts by air-con specialists and alfa specialists not being able to highlight a fusebox issue...hmmm.

Big thanks to shrew and fg for the helpful encouragement, as I don't think I would have had the confidence to question the original suggestion from my garage without some solid backup such as I got from shrew!

bring on the sunshine!!
Cheers
Iain

[PETR0LHEAD]

glad you got it sorted mate

bloomin fuse eh!

enjoy it, but now its all freshly gassed etc, never leave it idol, even if you dont need it, run it for a while once a week, or whenever you think about it.

odd i know, but using it, will save it!

cheers chap

glad you found it useful somehow.

shrew

[keithyboy]

My A/C dumped all its gas in about April but went unnoticed until June because the weather wasn't very warm. It took me until this week to get a new hose on there. My mate spent 2 hours vacuuming the system out and refilling it but the long spell of inactivity doesn't seem to have done it any good. It's gas-tight but the compressor isn't doing much.