My description is probably fairly poor. It sounds kinda lumpy/pulsing to me:
Tapping.. well that's coming from the right hand cylinder head, tappets I guess. Not sure what, if anything, I can do about that.
Sounds fine to me except for the tappet. I suspect you've got one with the sunken insert as it sounds exactly the same as my mates did when he had that problem. Did you check them before putting them back?
I did, they looked OK to my untrained eye. I believe they weren't in the affected range either, from memory.
Perhaps this is just gems vs Thor then. I'll have to find someone else with a Thor to listen to I guess.
Flipping back to ac, checked back of hevac and getting a healthy 12+ volts on the clutch engage line. Lo and behold, clutch has engaged as it should.
Still not getting anything anywhere near cold in the cabin though, even after 5 minutes. I don't really get how the compressor can be running but the vents aren't chilling, unless the compressor is barely working?
It may just be too low on gas to perform properly, but high enough the pressure switch hasn't stopped it running.
I'd say go to Halfords and take advantage of the no improvement no charge thing. It's something along the lines of if they can't get it at least 1c lower, there is no charge. They should recover the refrigerant, vacuum it down and refill it. Admittedly with an automated machine but still - short of finding a proper A/C place that do it manually its the next best thing.
Just my two penneth. I messed about with my a/c and discovered a hole in the condenser. Top left corner as you look at front. Everything was working and the air did seem a little colder but maybe that was just in the mind. I fixed the hole then it held a vacuum. Regassed and bobs yer uncle.
If he has the usual condenser hole, there will be no gas, and the compressor shouldn't run at all. The fact that it is and the discharge line is getting hot suggests it is compressing something. Took a look at a friend's Polo at work today, and it is doing the same thing.. discharge is very hot, but there is no cooling effect and the suction line is ambient. It's got a leak, but it hasn't yet lost quite enough to trip the low pressure cut off.
It's under this magical 'warranty' thing though, being 18 months old, so what looks to be a leak on the condenser will be VW's problem.
My clutch was engaging and I had a hole in the condenser. When they first put it on the vacuum, it wouldn't hold one. I fixed the leak and then took it back. When they put it back on, it held a vacuum and then they recovered some refrigerant. Reckoned it could have gotten air locked which accounted for some refrigerant in it despite having the hole.
Re pressure, I took it to an air con specialist I know last week as part of this diagnosis process and he reckoned the pressure was OK on both low and high pressure sides, with it not running. The clutch wasn't playing ball at the time so that's as far as we went.
The air lock suggestion is intriguing. That would account for all the symptoms seen thus far. Is that something anyone else has come across?
But was it vacuum tested first?
The machine at my local place is automated. It does a 5 minute vacuum test, then after that does a 20 minute or so refrigerant recovery and leak test, then finally injects new refrigerant. If it doesn't pass the vacuum test, it wont go any further.
Mine didn't vacuum first time and I didn't know where to begin looking for a leak. The guy bypassed the vacuum test and injected 100g of refrigerant. Straight away we could hear it was leaking and where from. Top left of condenser.
This is what happened with mine.
If the clutch engaged with a hole in the condenser, then either someone has screwed around with the wiring, or the pressure switch responsible is faulty. There cannot be refrigerant under pressure in an open system bar vapours in the lines. The pressure switches are on the high side of the system, where there will be zero pressure above atmosphere.
Back to OP though, you may have a blocked expansion device in the evaporator, though if you did, I would expect the pressure to build up very quickly to the point the high pressure cut off stops the compressor running. If the clutch is now not engaging though I'd still say its just losing gas at a rate the low pressure has stopped it running. I'd take a look if you weren't at the wrong end of the country :)
Have it recovered, have a nitrogen test done at 3-400psi (simulating high side operating pressure throughout), then if that passes the soapy water spray test on everything accessible and the pressure doesn't drop after leaving it some time, have it charged up correctly to the plated charge. A vacuum test can pull small leaks closed, especially on perishable seals like the o-rings.
Thanks Sloth, that sounds like a sensible way to go with the aircon.
Sloth wrote:
There cannot be refrigerant under pressure in an open system bar vapours in the lines. The pressure switches are on the high side of the system, where there will be zero pressure above atmosphere.
Like I say, when I took it in, it wouldn't hold vacuum, so they injected 100g of refrigerant. When I fixed the leak and took it back, it held vacuum and then they recovered more refrigerant than they'd put in and were puzzled. They surmised an airlock.
Well lots has happened since last year, but my new issue is a failed MOT due to emissions (high CO) :(
Wondering if a fuel treatment and/or ragging will fix it. Its been laid up for over a month so that probably hasn't helped either.
It might - new air filter may also help somewhat, Is it on petrol or LPG? (I'd suspect petrol?). It may be a sign of a failed cat or lambda sensor, worth checking what the fuel trims are showing if you can see them at all?
Petrol, still haven't sorted the LPG on it :(
I've not seen it yet, just checked the MOT status online and saw the failure.
Filter isn't that bad, but could probably get one today. Will plug nanocom in when I get back and see if it'll talk to the engine ecu at all.
What happened with this project?
Looked interesting!
H