GQ - Air Conditioning Issues

[dieseldude]

Can anyone please comment on why my aircon is playing up?

It works fine when the truck is cold and is consistent until the truck starts to heat up. At this point, it appears to cut out. Then, periodically, it comes on for a short time and then cuts out again.

This is really frustrating!

I had the system regassed and serviced last summer. I seem to think that if the system needed a regas again, it would just simply start getting warmer over time, not come on really cold and then cut out all of a sudden before coming back on again.

Any ideas?

Much appreciated

[dieseldude]

Do these systems have thermostats?

If so, are they dependent on the outside air temp?

I know that it appears to work really well (or a lot easier) when the outside temp is cooler. (such as night time/ early morning).

When it is hot outside, it really struggles to cool anything. Not the inside of the car as such, but the air that comes from the vents doesn't appear to be able to get cold....

Any ideas?

[MyGQ]

Does your engine temp rise to or above 3/4? if so thats your problem, they usually cut out when they get too hot.

I had the same problem with mine. it was working great when cold but after the engine got hot it cut out, though my problem was a seized Thermo fan on the front of the A/C unit and was not cooling properlly the gas, so it was just rising the temp of the engine.

[blade828]

sorry to ask another question in your thread but since were talking about air cons... how many revs does your engine rev up when you turn your a/c on (anyone)? mine goes up by around 400 revs, doesnt blow out cold air. seems a bit to high revs.

[MyGQ]

Mine drops revs when i put mine on, dunno why

[suzy]

Can anyone please comment on why my aircon is playing up?

It works fine when the truck is cold and is consistent until the truck starts to heat up. At this point, it appears to cut out. Then, periodically, it comes on for a short time and then cuts out again.

This is really frustrating!

I had the system regassed and serviced last summer. I seem to think that if the system needed a regas again, it would just simply start getting warmer over time, not come on really cold and then cut out all of a sudden before coming back on again.

Any ideas?

Much appreciated

I'm not the best when it comes to car a/c's so i'll give it a go.

First check that the fan comes on in front of the condensor?
you said when it heats up it cuts out,maybe the fan isn't comig on and it is getting to hot.

as the air gets colder coming out of your vents the condensor will be heating up at the same time you might not be able to get rid of the heat.

You said it was regassed?
did they find a leak or just regass it?
Normally if an aircon needs gas it's because it's leaked out.

It may be over charged causing high pressure cut out.

start the car and open the bonnet and turn th a/c on and watch the pipes,if they frost a little then just go moisty it's alright.
if it frost up heaps there's a little problem
maybe a gass leakage?
Could be youe TX valve playing up.


hope this helps

[dieseldude]

Excellent replies!

I'll open the bonnet and sight a few things and try to come back with a more thorough answer or problem.

I know that the engine pretty much never gets to 3/4 temperature, so I doubt it is cutting out due to this.

Although, the fan in front of the condensor not working may be a reason why it is only working when cold.

Thanks again.

I'll investigate and come back with my findings!

[snowy365]

Always be carefull with this so called re-gassing that goes on...Theres a lot of scum bags ripping people off out there.

With your rpm, it should increase for a moment prior to the compressor building up head pressure and slowing down the motor again.

If the compressor cuts in and out constantly it would usually be caused by the low pressure switch cutting it out i.e low on gas.

There are 2 pipes connected to the compressor, the larger of the 2 will be cool if not condensating if the gas charge is near normal...use this as a guide.

It is worth while checking if the heater valve and heater bypass flap are working properly.

Hope this answers a few questions.

[CB0569]

Just a quick question.
At the firewall you have 2 pipes 1 thick and 1 thin.The thin one should either be cold or have condensation on it.This will tell you if the A/C is functioning correctly.

IF COLD WITH A/C ON:
You could have a hot air from the heater fighting against it(eg cold + hot air = warm)

IF WARM WITH A/C ON:
This means that it COULD be low on gas.Other things that will cause this can be a)High pressure switch could be cutting it out and once the high pressure reduces it will cut back in or b)Thermostat could be out of adjustment.

Try these first and see how you go.
As far as my rpm goes it idles at 750 normally then with A/C on it goes to 850.

Cant tell without finding out what motor you have.
Regards
Craig