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Author Topic: help required 95 2.0 rxe  (Read 8443 times)
jon80y
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« on: July 16, 2007, 03:25:07 am »

i have 2 major probs with my 95 rxe
1 - only high speed on fan motor
2 - a/c pumps warm even though gas high pressure and compressor running

i have read previous threads and am sure i can fix the motor fault now - thanks to those who posted on these threads,

but my air con problem needs addressing , when i swith the a/c controller to low or high a/c the clutch cuts in but there is no cold air, i took the car to a local garage who hooked up to regas and then told me my pressures were fine so gas is not the problem , any ideas please - thanks in advance john
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roy4matra
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« Reply #1 on: July 16, 2007, 11:33:23 am »

i have 2 major probs with my 95 rxe
1 - only high speed on fan motor
2 - a/c pumps warm even though gas high pressure and compressor running

i have read previous threads and am sure i can fix the motor fault now - thanks to those who posted on these threads,

but my air con problem needs addressing , when i swith the a/c controller to low or high a/c the clutch cuts in but there is no cold air, i took the car to a local garage who hooked up to regas and then told me my pressures were fine so gas is not the problem , any ideas please - thanks in advance john

The first problem is the resistor pack has failed and you need to replace it.  The fan will work on it's highest speed as that is a direct feed.  All other (slower) speeds go through the resistor pack.

The second problem is probably linked to the first.  The air con. cannot work (it will not be authorised) without the heater fan working otherwise you would end up with a block of ice!  So replace the resistor pack first and then see if the air con. is working again.  If it still does not work, come back to us at that time.

Roy
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Lennart Sorth
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« Reply #2 on: July 18, 2007, 07:52:01 pm »

The heater-fan resistor was covered in this thread: http://www.matrasport.dk/forum/index.php?topic=247.0

On my J63 the AC stopped working when the connection to the extra radiator fans was bad. As soon as I soreted out the connector (on the fan itself), the AC started workeing again.

PS: I had many different problems with the AC on my 1994 J63, but after replacing a range of valves, hoses and connectors, it finally was working beautifully ... and then I sold the car ?!? :-)

/Lennart
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jon80y
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« Reply #3 on: July 18, 2007, 11:05:49 pm »

The heater-fan resistor was covered in this thread: http://www.matrasport.dk/forum/index.php?topic=247.0

On my J63 the AC stopped working when the connection to the extra radiator fans was bad. As soon as I soreted out the connector (on the fan itself), the AC started workeing again.

PS: I had many different problems with the AC on my 1994 J63, but after replacing a range of valves, hoses and connectors, it finally was working beautifully ... and then I sold the car ?!? :-)

/Lennart

thanks for the reply,  interesting that you mention the rad fans , as these come on when you turn on the a/c switch , i was not sure if this is standard or not , i will be back under the bonnet this weekend and will let you know how i get on - thanks again john
« Last Edit: July 19, 2007, 08:39:34 pm by Lennart Sorth » Logged
roy4matra
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« Reply #4 on: July 19, 2007, 12:58:01 am »


The heater-fan resistor was covered in this thread: http://www.matrasport.dk/forum/index.php?topic=247.0

On my J63 the AC stopped working when the connection to the extra radiator fans was bad. As soon as I soreted out the connector (on the fan itself), the AC started workeing again...

/Lennart

thanks for the reply,  interesting that you mention the rad fans , as these come on when you turn on the a/c switch , i was not sure if this is standard or not , i will be back under the bonnet this weekend and will let you know how i get on - thanks again john

Yes that is correct John.  The radiator fan is two speed and when you turn the air con. on the radiator fan must come on at it's low speed setting.  If this doesn't work for any reason, the air con. is not allowed to work, as Lennart indicated.

Roy
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jon80y
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« Reply #5 on: August 01, 2007, 10:17:53 pm »

thanks for all your help so far, but i still need some advise, i have replaced the fan speed resistor and now have all heater / fan / damper functions running as normal - only problem is - STILL NO A/C ( COLD AIR ) ....... any suggestions please .... thanks in advance ... john
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Lennart Sorth
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« Reply #6 on: August 02, 2007, 12:02:54 am »

STILL NO A/C ( COLD AIR ) ....... any suggestions please .... thanks in advance ... john
you should have two fans on the radiator out front, - my guess is the one isn't getting any juice to operate.
My J63 had this problem, and the aircon (correctly) cut out, as the pressure in the aircon system very quickly became too high, whereby its internal overpressureswitch cut in.

The fans on the radiator (and more precisely the AC condenser, which is mounted ahead of the radiator) should be running as soon as the AC is turned on. I can't remember precisely, but maybe only the one of them is linked to the AC.

On my J63 (1994) it was simply the connectors on the fan motors themselves that had corroded (hey, here we go again :-) )

/Lennart
« Last Edit: August 05, 2007, 04:20:43 pm by Lennart Sorth » Logged

Lennart.Sorth@matrasport.dk
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roy4matra
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« Reply #7 on: August 03, 2007, 09:36:44 pm »

thanks for all your help so far, but i still need some advise, i have replaced the fan speed resistor and now have all heater / fan / damper functions running as normal - only problem is - STILL NO A/C ( COLD AIR ) ....... any suggestions please .... thanks in advance ... john

O.K. if the internal heater fan is now working on all speeds, and you must have the fan at least on position one; and the fan on the radiator switches on when you activate the air con. then can you hear a loud click from the air con. compressor pulley when you switch the air con. on?  This is the electro-magnetic clutch engaging.  When the air con. is not switched on the air con. pulley free wheels and the pump is not driven.  When you switch the air con. on, it should engage and drive the pump (compressor).

If it is not engaging then you will need to find out why or get the system checked.  If you can hear it engage and you still get no cool air, then it suggests there is either too little gas, or the compressor is not working properly.  You will need to get the system gas checked and refilled if low.  Air con. systems are supposed to be refilled every four years as there is always a slight leakage.  However, if there is no gas it should be checked for major leaks, repaired as necessary, and then refilled.

Roy
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jon80y
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« Reply #8 on: August 05, 2007, 01:10:35 am »

thanks again to all for your input,

to clarify - a/c still pumps warm, 
(overview)
all fan speeds now work ( resistor replaced )
both primary condensor fans cut in and run when a/c is switched on
clutch on a/c pump cuts in and runs when a/c switched on
all relays on a/c circuit replaced
gas pressure on riser and return checked - all ok

i am now looking at either
1 - the condensor could be shot
2 - the pump could be shot
3 - the a/c temp regulator could be giving incorect reading

the only problenm is they all mean strip out replace and re-gas - this also means a big bill........that is unless someone can come up with another possible cause.... thanks again john
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roy4matra
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« Reply #9 on: August 05, 2007, 10:43:24 am »

thanks again to all for your input,

to clarify - a/c still pumps warm, 
(overview)
all fan speeds now work ( resistor replaced )
both primary condensor fans cut in and run when a/c is switched on
clutch on a/c pump cuts in and runs when a/c switched on
all relays on a/c circuit replaced
gas pressure on riser and return checked - all ok

i am now looking at either
1 - the condensor could be shot
2 - the pump could be shot
3 - the a/c temp regulator could be giving incorect reading

the only problenm is they all mean strip out replace and re-gas - this also means a big bill........that is unless someone can come up with another possible cause.... thanks again john

From the above I have to say it is looking like the air con. compressor pump is U/S. :-)

Roy
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jon80y
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« Reply #10 on: August 05, 2007, 02:18:21 pm »

thanks roy, forgot to mention that the pump is active, the top pipe gets hot within seconds of turning a/c on, so high pressure, heated gas/oil is making it as far as the condenser .

as for what is happening with the system after that , is proving to be a guessing game, ...... i think it might be time to call  in at the local garage again for some more " oh ... ahh ... now this is gonna cost ya mate..! "

Either way if i lay out on a second hand pump from my local breaker ( 3 Espace to choose from ) i could end up with the same fault  and re gassing charge....

cheers john
« Last Edit: August 06, 2007, 05:00:35 pm by Lennart Sorth » Logged
roy4matra
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« Reply #11 on: August 06, 2007, 04:17:18 pm »

thanks roy, forgot to mention that the pump is active, thge top pipe gets hot within seconds of turning a/c on, so high pressure, heated gas/oil is making it as far as the condensor.

Well you said previously the gas pressure had been checked.  If someone has taken high and low pressure readings when the system is running these will tell whether the problem is simply low gas or the compressor not working correctly, etc.  Someone who knows air con. systems properly can tell a lot from reading the gauges and how they react, how quickly the pressure rises, what are the upper and lower limits, etc.  Too much gas can be just as bad as too little.

Personally I wouldn't use a dealer, certainly in the U.K. unless you know they really have someone who really knows air con. systems fully.  Most dealer personnel only have a rudimentary knowledge and most if not all garages don't have inert gas to check for leaks - which means they test systems by putting air con. gas in!  So if it is suspected to have a leak, they are polluting the atmosphere knowingly.

An air con. specialist should be much better, but ask a few questions and see how they reply.  Ask what they use to check for leaks - there are 'sniffers', and ultra violet light with dyes in the gas, as two examples, but ask what inert gas they use to check a system and if they can't give a satisfactory answer, or show you the gas cylinder, ask why you should use them!  (the answer should be nitrogen)

The condenser is just a heat exchanger and if it is airtight, which it must be if the gas is still in the system, then the hot high pressure fluid from the compressor is cooled by the airflow through the matrix, and then it stored and dried in the accumulator.  When it passes through the orifice, it drops in pressure and expands and passes through the evaporator inside the car, and as air is blown over the evaporator by the heater fan it is cooled, since the fluid changing to gas takes heat from its surroundings i.e. in the evaporator.  The low pressure hot gas now returns to the compressor where it gets compressed back to a fluid and the cycle starts again.

If you say the pressures are fine, and the fans are working, I don't see why it is not working.  So that suggests to me that the pressures are not actually what they should be, or the compressor is not circulating the gas correctly.  If the system has been open to atmosphere at any time during its life for just 2 hours, the system has been compromised and the dryer is probably U/S, since it will become saturated with moisture from the atmosphere in just that short a time.  This is why any air con. joint that is opened must be sealed immediately.  Again garages often never do it, as they don't understand the importance, and simply leave the pump or pipes open!  Fatal.

A blockage could stop circulation but it will cause the pressures to be wrong.  If the compressor is faulty it should cause incorrect pressures.  If the gas is low or high, it will cause incorrect pressures.  If the orifice is not working in some way, it should cause incorrect pressures.  So you see, if the system is air tight and hasn't leaked, then the two pressure readings taken whilst the system is supposed to be working should indicate where the fault lies.

It's not a case of guesswork.  The correct diagnosis leads you to the correct conclusion.

Roy
« Last Edit: August 06, 2007, 04:21:26 pm by roy4matra » Logged

jon80y
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« Reply #12 on: August 06, 2007, 10:56:42 pm »

hi roy, thanks again for the info,
spoke to the guys (today) that checked gas when i started on the quest for an icy blast !!!! ...

they have told me that as the system was on shut down ( due to fan speed resistor ) the initial readings were probably wrong, and they will check for me to see if now generating high and low pressure at each end of the cycle.

if no change is shown then they beleive the pump is not working correctly.

does this sound correct asumption ? -  thanking you in advance  - john
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roy4matra
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« Reply #13 on: August 07, 2007, 07:40:22 am »

hi roy, thanks again for the info,
spoke to the guys (today) that checked gas when i started on the quest for an icy blast !!!! ...

they have told me that as the system was on shut down ( due to fan speed resistor ) the initial readings were probably wrong, and they will check for me to see if now generating high and low pressure at each end of the cycle.

if no change is shown then they believe the pump is not working correctly.

does this sound correct assumption ? -  thanking you in advance  - john

Yes, that would be right John.  When the high and low pressures are the same or almost the same it indicates the compressor has failed, if there is gas in the system.

Roy
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jon80y
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« Reply #14 on: August 07, 2007, 10:53:32 pm »

hi, back again !!.

can you please tell me, when removeing the compressor is there any way to keep the system charged during replacement to avoid re gassing charges, or will i loose all gas / oil if i remove the pipes from the compressor.  - cheers john
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