Aircon not cold - where to start?

[jerrytlr]

OK I don't want to tempt fate, but have had my 95 2.5 DT for a couple of weeks now and done around 1,500 miles with no major issues at all apart from drivers window mech teeth worn (already fixed; easy and cheap). It is a great car and I am, so far at least, very pleased with it. Working EAS is superb.

The only significant problem I have is the aircon is not cold.

I know this could be due to any number of things, but was wondering what you would recommend as the first diagnostic step.

What I know so far is:

- no book symbol, HEVAC display is working fine, so I assume there are no HEVAC fault codes?
- blender seems to work OK, in that it will change air temp from ambient to hot as instructed, just won't blow cold

My immediate thought is leak test/regas, but surely if pressure was low I would be getting a fault code/book symbol?

Is it easy to check to see if compressor is running? That power is getting to the compressor clutch (for example, should there be an audible click when aircon swithed on, or a change in engine revs?)

I don't have RAVE yet btw, been trying to download it but without success (so far), I appreciate the info I need is probably in there, but I would like to make a start on sorting this now, so I would greatly appreciate some pointers re where to start!

Cheers

Jerry

 

[jerrytlr]

I really should do the obvious checks before asking questions on here - trouble is I don't think of them until I'm writing the post!

Just been out to the car and checked; the engine idle speed does change quite noticeably when you switch the aircon on and off - so, is it the ECU doing this, or does it tell me that the compressor is putting load onto the engine as it should?

Over to the experts ;-)

Cheers,

Jerry

 

[Irishrover]

The aircon compressor clutch operation can be seen by looking at the pulley. The compressor shaft is stationary when the compressor clutch is disengaged, the pulley will be freewheeling. You will hear a click, indicating that the clutch has engaged and the compressor shaft can be seen to rotate at the same speed as the pulley.
Secondly, with the aircon temperature set to "Low" and the compressor running, one of the hoses from the compressor should be very hot and the other freezing cold.
Also make sure the Condenser, looks like a radiator, located directly behind the radiator grille and has two electric fans attached, is not choked with muck and leaves etc. Give it a good blast through with a pressure washer to ensure free airflow over the cooling fins.
If that fails, take it to one of the places that do free aircon performance checks on a "No fix-no charge" basis. Kwik Fit used to do it.
The engine speed does drop for a split second when the compressor kicks in but the engine ecu detects this and increases the engine speed to compensate automatically.

 

[The Mad Hat Man]

The aircon compressor clutch operation can be seen by looking at the pulley. The compressor shaft is stationary when the compressor clutch is disengaged, the pulley will be freewheeling. You will hear a click, indicating that the clutch has engaged and the compressor shaft can be seen to rotate at the same speed as the pulley.

Only if there is enough gas (pressure) in there to allow the trimary switch to operate.

It also helps. Jerry, if yu change yo UserCP to show where you are.

 

[bigdel]

Kwik Fit are doing an aircon recharge for 49.99 at the mo. my colleague's aircon went warm after he'd had a minor shunt and they re-gassed it, but didn't charge him cos the accident had put a hole in the heat exchanger or a pipe and the gas wouldn't stay in! could be worth a looksee

 

[jerrytlr]

Only if there is enough gas (pressure) in there to allow the trimary switch to operate.

It also helps. Jerry, if yu change yo UserCP to show where you are.

Good idea - now done! No Kwik Fits near me, sadly.....

So I get the click; the engine speed drops for a moment - so I must have at least enough pressure to get the trimary swith to operate, yes? I will look at the shaft tomorrow in daylight just to be 100% sure the compressor shaft is turning.

Will then feel the pipes and report back....

Please note though - the aircon currently makes NO difference at all, it's not just that it is a bit weak.....

Thanks for all the help so far

Cheers

Jerry

 

[The Mad Hat Man]

If the compressor is kicking in, chances are its just low on gas - Halfrauds sell the kits.

 

[jerrytlr]

If the compressor is kicking in, chances are its just low on gas - Halfrauds sell the kits.

Erm - I thought if the system is low on gas, the trimary switch will prevent the compressor from kicking in? Or is it a case of 'low' versus 'completely empty'?

Cheers

Jerry

 

[The Mad Hat Man]

its how low is "low" - yu normally get about 10% loss every year, so the pressure in the system will slowly degrade. If you have a leak (hole in system) then the chances are yu will have no pressure. My understanding is that if the compressor cuts in, then a significant leak is unlikely, and a top up, will be sufficient.

 

[wammers]

Mad is correct. There maybe enough pressure in the system to allow compressor to come in, but that does not mean there is eough to allow the system to cool properly. Think you need a recharge.

 

[Datatek]

Mine had the same symptoms as yours, it was the condensor failed. Easy DIY to change the condensor then off for a re-gas. I used a cannister from Ebay everyone says don't but it's still working 2 years on. (Ebay is cheaper than Halfrauds and they ain't in France)

 

[jerrytlr]

Mine had the same symptoms as yours, it was the condensor failed. Easy DIY to change the condensor then off for a re-gas. I used a cannister from Ebay everyone says don't but it's still working 2 years on. (Ebay is cheaper than Halfrauds and they ain't in France)

Sorry if this is a bit of a dim question, but how did you know the condensor had failed? was it obviously leaking? Dye?

If it ever stops raining, I will pop out and have a poke around and see if I can spot anything....

Best place to get a replacement condensor without needing a second mortgage??


Cheers,

Jerry

 

[Datatek]

Sorry if this is a bit of a dim question, but how did you know the condensor had failed? was it obviously leaking? Dye?

If it ever stops raining, I will pop out and have a poke around and see if I can spot anything....

Best place to get a replacement condensor without needing a second mortgage??


Cheers,

Jerry

Oil and dye stains on the top left corner of the condensor. Got my replacement off UK Ebay, £79

 

[jerrytlr]

Well it still hasn't stopped raining but I had a quick look anyway - it is very hard to see if the compressor shaft is turning as it is so close to the radiator; however one of the pipes leaving it does get hot so I am pretty sure it is turning OK.

I guess I need to remove the front grill to check the condensor for evidence of leaks, no time to do that now. I did however notice that the two electric fans don't run when the a/c is switched on - should they run all the time that the a/c is on, or are they only switched on when required?

Cheers

Jerry

 

[wammers]

Fans only run when refridgerant is hot. You will have to remove slam panel to check top of condensor.