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[Richard A]

Went today to have the air con system re-charged, all went well ie no leaks, however the pump will not kick-in to suck the required weight of gas.
Apparently about 180 grams is pressure fed, then the pump sucks the rest up to 500/600 grams. The engine as it should changes revs as air con is switched on and off, all fuses are fine, I have checked K22 (white) Aircon coolant pump relay and K60 (green) Aircon compressor relay, both seem fine. Any ideas please, or is it the pump ?  
regards
richard a

[Kevin Wood]

Is the clutch on the front of the aircon pump pulling in? (do the 3 little cylinders on the front of the pulley start rotating?)

Was the pump running before the gas was evacuated?

There's a pressure switch that will inhibit the pump below a certain high side pressure, IIRC, so maybe the charge in the system hasn't reached the required pressure or the pressure switch is fubar.

Kevin

[Marks DTM Calib]

Might need a bit more than that weight to get the low side pressure above the trigger threashold, they should be monitoring the low side pressure.

As for the sucking the rest in, not sure how thats ever gonna happen!

What you normally do is discharge the system, vac it out for 30 mins or so and then deliver a set weight of gas, about 1Kg in the case of the Omega. Then fire the engine up and check the high and low side pressures.

Did they vac and check the system or just dump a load of gas in?

[Richard A]

Hello Kevin, thanks for the info, 1) Should the 3 little cylinders rotate and when. 2) Not sure now if the pump was running. 3) Can the pressure switch stick and where is it.
regards
richard a

[Richard A]

Hi Mark, they did discharged the system, then two types of additive were put in (lubricants I think), then a 150 grams load was used, engine started, air con on "low", but the pump would not click in. He said call back tomorrow and they would contect the car to some type of electronic gizmo (not a "tech 2") for the cost of £65 to help find the problem, then plus £45 for the recharge, plus the cost of sorting out.
regards
richard a

[dbug]

Hi
They should vacuum out the system then check for leaks by holding vacuum for 20 - 30 mins.  Should then put in additives (lub oil for compressor + u/v dye to show up any subsequent leakage).  Then add 960gm (? i think thats right amount) of gas.  Then fire up engine, run a/c, check cold + hi/low pressures. Job done.

If a/c compressor breaked - normally a stuck clutch.  You can check this by pulling elec connector plug off compressor & putting 12v directly across the 2 pins on the comp - ensuring correct polarity!  If clutch ok you will hear it pull in with a loud click - if breaked silence!

Hope this helps

[Richard A]

Thanks "dbug", yes that is what went on (your weight maybe a bit high). Update: the aircon compressor pulley rotating ok, but the front plate is still, can rotated by hand without a problem.
regards
richard a

[Richard A]

Could someone describe how and when the clutch cuts in and out on the aircon pump.
many thanks
richard a

[Marks DTM Calib]

Thanks "dbug", yes that is what went on (your weight maybe a bit high). Update: the aircon compressor pulley rotating ok, but the front plate is still, can rotated by hand without a problem.
regards
richard a

No, that weight is spot on.....check the label on your slam panel!

Ok, the aircon clutch will only cut in if the low side presure is above 30 or so PSi and trips out again if the high pressure trip kicks in (about 400psi on the high side).

So, you need a minimum amount of gas to get the low side switch to allow the clutch to engage.

Its worth checking the wires to the trips etc and also the fuses in the engine relay box.

Did they confirm if there was any gas in it before the discharge?

[Richard A]

Thanks, yes there was gas in the system. Which fuse in the engine bay, cheched relays, I think.
regards
richard a

[Richard A]

sorry, where are the trips !

[Richard A]

Mark, thanks for your time. Just checked, taken out all the fuses in relay bay, all ok, changed rad some months ago are the sensors near by ?, could I of disturbed the connectors ? were do I check. The £45 regas could start to climb to £200 + unless this can be solved.
regards
richard a

[MutantCav]

I have a good aircon compressor pump here off a 98 3.0 v6 if you do need it...wont cost an arm and a leg either!

[Marks DTM Calib]

Mark, thanks for your time. Just checked, taken out all the fuses in relay bay, all ok, changed rad some months ago are the sensors near by ?, could I of disturbed the connectors ? were do I check. The £45 regas could start to climb to £200 + unless this can be solved.
regards
richard a

When you changed the rad, did you get ALL the connectors on the passenger end of the rad back in properly, including the very lowest one?

[Richard A]

Hi Mark, I think so, why what is it todo with the aircon ?
regards
richard a