Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Richard A on 06 May 2008, 14:45:05
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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
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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
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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?
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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
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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
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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
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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
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Could someone describe how and when the clutch cuts in and out on the aircon pump.
many thanks
richard a
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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?
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Thanks, yes there was gas in the system. Which fuse in the engine bay, cheched relays, I think.
regards
richard a
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sorry, where are the trips !
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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
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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!
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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?
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Hi Mark, I think so, why what is it todo with the aircon ?
regards
richard a
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Hello Chris, I maybe back to ask the price, thanks for the offer.
regards
richard a
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Hi Mark, I think so, why what is it todo with the aircon ?
regards
richard a
If not correctly connected it will stop the pump engaging.
It provides the path to 0v for the low side of the pump and opens if the rad temp gets to high (the heat produced by the aircon heats the evaporator in front of the radiator up and hence lowers the cooling capacity of the rad by pre-heating the cooling air)
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O' sh1t, didn't understand, will check in the morning, what happens if the unit is not working, will the connector still carry the single to the aircon pump ?
regards
richard a
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I think the key here is that the 150g charge they have added (where did that figure come from?) is not likely to bring the pressure up high enough to bring the pump into operation. They should be able to monitor the low side and high side pressures with the air con kit they have connected. As Mark says, until the low side is relatively close to the fully charged pressure the system will be completely disabled. Not sure what electronic gizmos will tell them. Tech 2 or equivalent will not tell them anything. It's the 2 pressures and the volume of refrigerant added that are important.
Kevin
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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 gas weight is correct for 98 2.5 V6 Elite!! Also 155gm lub oil required. Irrespective if enough lo pressure to allow clutch on compressor to engage, if clutch f*cked (seized) it will never engage. It costs no money to check whether it is seized! If seized the first thing u must do is replace it b4 doing anything else which may cost otherwise any cost u incur could be wasted. Check it out as my previous reply. Note the compressor is an rsol to swap out - i know i've done one.
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Bad news for you .. perhaps .. :(
The compressor on mine went, contaminated the whole system, caused the expansion valve to fail open, and partially blocked the filter/dryer... :(
Local air con shop did a reasonable job .. but the total bill was just over £900 ... :(
Major expense was a full system flush to get all the crap out and I saw what was in the pipes before they started .... horrible dark grey viscous gunge which if you rubbed a drop between your fingers you could feel the metallic particles .. it felt like fine valve grinding paste.. ..
Followed by a Compressor, Expansion valve, filter dryer + labour to change ..
:(
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Bad news for you .. perhaps .. :(
The compressor on mine went, contaminated the whole system, caused the expansion valve to fail open, and partially blocked the filter/dryer... :(
Local air con shop did a reasonable job .. but the total bill was just over £900 ... :(
Major expense was a full system flush to get all the crap out and I saw what was in the pipes before they started .... horrible dark grey viscous gunge which if you rubbed a drop between your fingers you could feel the metallic particles .. it felt like fine valve grinding paste.. ..
Followed by a Compressor, Expansion valve, filter dryer + labour to change ..
:(
:o :o
2nd user compressor - £30, +£45 to vac system, check for leaks and gasup/lubricate etc - A/C :y :y :y
U were very unlucky :( :(
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I don't think a normal vac would have shifted the crap, so agreed to the flush .. seemed a tad daft to fit new parts to a contaminated system. :(
I went for the "full monty" repair as I've only just bought the car (January) with the intention of keeping it along time ... at least it now has a 2 year warranty on the air con system !!!
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did they change the condensor?
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did they change the condensor?
Nope .. they said the flush would clean it sufficiently ... :-/
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you cant effectively clean a condensor,but you have a 2 year guarentee therefore it will be their problem if you have a problem :)
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the only condensor you can really clean is a serpentine condensor,practically obsolete for 30 years
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you cant effectively clean a condensor,but you have a 2 year guarentee therefore it will be their problem if you have a problem :)
I'm guessing if it lasts 2 years it'll last longer .. ie .. any failure wil occur quickly ??
At least I hope thats the way it works ..... :-/ :-/
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believe me if anything is going to happen as a result of not changing the condensor, it will happen well within 2 years.
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Was going to say £30 for the compressor second hand +p&p
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Chris, we dont have any evidence to say the compressor is faulty.
The a/c guy should have had a gauge set connected when they started to re-fill, as the low side pressure rises to 30 psi then you would hear the low pressure cut-out switch click. After that the compressor clutch should pull-in and the drive plate start to rotate.
You then add more gas, checking that the low side regulates correctly at 30 psi and that the high-side rises normally. Full fill is 960 grammes.
Static pressure (compressor not running and system cool) is around 75 psi. The gas cylinder pressure is much higher than this so the compressor does not 'suck' in the refrigerant.
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True matchless we dont yet...but always nice to know the option is there if we find out the guy needs it? :)
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Thanks "Matchless", they did use a gauge set but did not hear the low pressure cut-out switch click, drive plate not rotating (can be turned freely by hand).
Just going to check connector as suggested by Mark.
regards
richard a
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But did they see 30+ psi on the low side before condemning it??
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But did they see 30+ psi on the low side before condemning it??
This is the key. They seem to have assumed 150g of refrigerant will be enough without checking pressures.
Kevin
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Matchless and Kevin, this is real service, thanks. Sorry don't know if they checked for 30psi, can I get the clutch to engage ie can I press any combo of switchs, all fuses and relays are fine but will look at connectors in the next hour, any other things to check ? Problem is I can't remember the last time I saw the plate rotating.
regards
richard a
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Matchless and Kevin, this is real service, thanks. Sorry don't know if they checked for 30psi, can I get the clutch to engage ie can I press any combo of switchs, all fuses and relays are fine but will look at connectors in the next hour, any other things to check ? Problem is I can't remember the last time I saw the plate rotating.
regards
richard a
As i've said previous replies this post - check compressor clutch operation b4 spending money!!
Check as follows - 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!
Free & takes 10 mins ;)
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Thanks "dbug", the car is on the drive of my house not on a ram, to access the pump from the top of the engine is err "tight", will give it a go.
regards
richard a