RangeRovers.net Forum banner

1 - 5 of 5 Posts

·
Premium Member
Joined
·
1,702 Posts
Discussion Starter #1
My scenario is slightly different to the symptoms being reported by Carl and the other recent posters.

Brief history, last year I used an Independent garage and had a new condenser fitted aswell as the little dryer bit that feeds into the bottom of it. It kind of blew cold air and then because the allocated 30 mins of British summer passed by (whilst I was having the work done), I didn't bother with it, until this Summer.

Just been down to Kwik Fit, as they promised not to charge me if there were any problems :pray: .

Apparently the system only had half of the 1.2 (kg, lbs, whatever) recommended weight in gas. They vaccumed and refilled the system, found no leaks - But when the AC is on, whilst the blowers constantly blow fast, the air seems to only blow very cold for about a minute before blowing less cold for a around the same time.

The young lad working on the car seems to think the compressor could potentially be faulty so did not charge me for anything :clap:

You can hear the compressor kick in regularly - Is that the actual problem?
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
1,851 Posts
Hi

The AC system monitors the temperature in the evaporator. If the air going out of the evaporator becomes too cold the ECU assumes that ice is forming on your evaporator and cuts the compressor clutch out until the temperature becomes warmer again. This is the cycling of the compressor that you hear.

In the tropics on my car the compressor cuts out and in twice every minute when the verhicle is stationary. The air out of the vents stays cold.

You have to make sure that the blend flaps are fully on cold air so it does not blend in hot air from your heater.
If it takes long for the temperature to go down after the compressor starts it might be a sign of a weak compressor.

Regards

Jos
 

·
Premium Member
Joined
·
1,702 Posts
Discussion Starter #3
Cheers Jos,

I will try and spend a little time this weekend and ensure the blend motors are not the cause of the temperature fluctuation.
 

·
Premium Member
Joined
·
1,410 Posts
The best way to see if the A/C itself is cooling properly is by monitoring the suction line in the engine compartment (the larger of the 2 lines going to the expansion valve - runs across the top rear of the engine compartment). If the ambient temp is more than 24-25 deg C, it will have condensation or even a light frost on it very quickly when the compressor is running. If it gets very cold quickly every time the compressor kicks in, it's likely not going to be the A/C itself.

I spent several years installing and servicing A/C's a while back, but I never saw a compressor that was not able to provide the necessary pressure and was fine otherwise. Is the compressor making any noises it shouldn't (rattles, etc.)? Compressors that are bad will leak - compressors that are very bad will leak very badly. All this is relatively easy to see with gauges connected to the A/C. If your high side pressures are not high enough, I'd be willing to bet that your expansion valve is heading south before the compressor - this is easy and relatively inexpensive to fix (do not use an OEM LR part). Also, there is oil in the A/C system and when there is a leak, oil will be pushed out too - so examine any 'damp' spots on air conditioning components.

Is the young techs reason for thinking the compressor is bad the temp fluctuation? It could also be that the HEVAC ECU thinks you are going to catch a cold and is blending in warm air as Jos mentioned. Temp sensors (ambient, evap, heater core) would be likely culprits.

The first things I'd look at based on probability are the electronics combined with a slow leak. Half a charge over a years time (0nly 600g!) can be quite difficult to detect. I find it hard to imagine that anyone would only half-fill the system :doh: . Start by very carefully examining all connections that were opened when the condenser and rec/drier were replaced.
 

·
Registered
Joined
·
701 Posts
Make sure that all your connections are tight. I had a fairly bad leak, until I tightened the bolts on the back of the compressor (go figure) and that solved the problem. Mine will go cold, and then not so cold, but that is just the a/c kicking on and off. Check it out in the engine compartment and see if the cold side is getting cold quickly. If it is, then start looking at the possibility of a blend motor failure, or interior temp sensor failure. I would also set the interior temp at the lowest possible setting to see if that makes a difference (not on the "auto setting).
 
1 - 5 of 5 Posts
Top