P38A Aircon won’t blow cold

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Datatek said:
Not so, there are things called fans to propel air through the aircon condenser and RAD and there are also a pair of fans in the cab heater unit to propel cool air into the cab.:cool:
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Yes, but it always seems to take longer if you're stationary.
Ie. Start engine, set air to max cold it's not going to blow cold straight away, it might take a minute or 2. If the car is moving that's more air than fans can shift so will get cooler a bit quicker
 
kermit_rr said:
Yes, but it always seems to take longer if you're stationary.
Ie. Start engine, set air to max cold it's not going to blow cold straight away, it might take a minute or 2. If the car is moving that's more air than fans can shift so will get cooler a bit quicker
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Low engine revs mean that the compressor is not functioning at full capacity. Of course it takes some time for the system to generate cold air in the cab from starting the engine, the latent heat in the pipes and heat exchanger has to be removed. I find mine works fine in traffic jams when the car is stationary.
 
Datatek said:
Low engine revs mean that the compressor is not functioning at full capacity. Of course it takes some time for the system to generate cold air in the cab from starting the engine, the latent heat in the pipes and heat exchanger has to be removed. I find mine works fine in traffic jams when the car is stationary.
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Hadn't thought about engine revs!! I feel silly now
 
Alright quick follow up for anyone interested.

The mechanic did a vacuum pressure test for leaks but couldn't find any. They said the gas was quite low, enough to get the compressor going but not enough to make things cold. So they regassed it and put some dye in to assist in future diagnoses of any leaks.
They also said the compressor itself sounded like it was on its way out so they gave it a little oil.

Anyway with just the regas we're ice cold!! :D:D
So I'll look at replacing the compressor at some point before it completely fails but I'm otherwise very happy at the outcome and have cold air in time for the Australian summer :)
 
enjoi said:
Alright quick follow up for anyone interested.

The mechanic did a vacuum pressure test for leaks but couldn't find any. They said the gas was quite low, enough to get the compressor going but not enough to make things cold. So they regassed it and put some dye in to assist in future diagnoses of any leaks.
They also said the compressor itself sounded like it was on its way out so they gave it a little oil.

Anyway with just the regas we're ice cold!! :D:D
So I'll look at replacing the compressor at some point before it completely fails but I'm otherwise very happy at the outcome and have cold air in time for the Australian summer :)
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Nice one. Thrills or should that be chills all the way:D:D
 
As a suggestion, I would not look to replace the compressor unless it actually fails. Run the air-con at least once a week to keep the seals working and circulate the oil. As you say, they have put tracer dye in the system so if the pressure fades then they can see where the leak is. A tiny pinhole leak might take a week or more to affect the cooling, but if the pressure falls then the compressor clutch will not engage - there is an over-pressure / under-pressure dual switch in the system.
 
P38 Monkey said:
As a suggestion, I would not look to replace the compressor unless it actually fails. Run the air-con at least once a week to keep the seals working and circulate the oil. As you say, they have put tracer dye in the system so if the pressure fades then they can see where the leak is. A tiny pinhole leak might take a week or more to affect the cooling, but if the pressure falls then the compressor clutch will not engage - there is an over-pressure / under-pressure dual switch in the system.
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Run the aircon all the time especially in winter to keep the electronics dry
 
Datatek said:
Run the aircon all the time especially in winter to keep the electronics dry
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I absolutely agree with that approach.
Question: in previous (less sophisticated) cars I would just put the heating on full and switch the air-con on, but how do I do that with the P38's climate control system? Easy enough to turn the air-con off, but how do you force it to stay on without freezing your butt off?
 
P38 Monkey said:
I absolutely agree with that approach.
Question: in previous (less sophisticated) cars I would just put the heating on full and switch the air-con on, but how do I do that with the P38's climate control system? Easy enough to turn the air-con off, but how do you force it to stay on without freezing your butt off?
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If you press the program button on the hvac panel it puts it in to ultimate demist mode which has aircon on to dry the front screen as well as heating but will only stay on for 10mins.
 
As long as you leave the aircon switched on (i.e. red light off), it is working regardless of heat setting. The HEVAC ECU measures evap & heater temperature and adjusts the flaps as required. Hence dry air, either hot or cold.
 
pwood999 said:
As long as you leave the aircon switched on (i.e. red light off), it is working regardless of heat setting. The HEVAC ECU measures evap & heater temperature and adjusts the flaps as required. Hence dry air, either hot or cold.
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As above. In addition I always run mine on manual as the random changes of blower speed and temperature on auto annoy me.
 
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