Weird air con issue

[Patrol'n]

Hi all,

I have a weird issue with my air con / cooling system ATM.

I recently found my air con warm, so i had it re-gassed, the mechanic found a leaking valve and replaced it, and advised my fan clutch was faulty, so I've replaced that with a brand new one.

Now I am finding that if I start the engine, and switch on the air con before the engine is up to temperature, it gets progressively warmer, and doesn't seem able to control the temp. I am switching the air con off before the temp needle hits half, so I don't get it too hot. I have found that it quickly comes back to its normal spot at about a quarter. Then I'm able to turn the a/c back on, and it's lovely and cold and the engine temp stays perfectly normal...

I drove several hundred kays last week, with air con, and it didn't overheat once at temp, even crawling over rocks and in soft sand. If I wait for the engine to come up to temp before switching on the a/c, I get no problems at all.

I have never encountered this issue before, despite having owned somewhere around 15 cars prior to this one, any ideas what I should be looking at please? Prior to getting the air con re-gassed, no issues with temp, although the air con had gone warm obviously.

(I should mention, it doesn't use any oil or coolant, makes good power, blows no smoke, leaks no oil, runs smoothly etc).

Thanks blokes, (and ladies if you're reading)

[Potsy]

Hi patrol'n. Is this going by your factory gauge or an aftermarket setup.
Also have you stopped to feel the engine or radiator to see if there is any difference in each instance.
Just a stab in the dark but I previously has a vehicle with very bad earths so if a component that draws a bit from the battery is switched on the factory temp gauge would jump up a little. Pain in the ass at night when I put my headlights on cus it would rise by 1/5 of the gauge.
Although your compressor would be belt driven the thermo fan on your condenser would draw from the battery.
Just a thought and good luck.

[Patrol'n]

Hi Potsy,

Thanks for that mate, it's via the factory gauge, which has seemed very consistent prior to this issue. My air con condenser doesn't have a thermo fan, so I'm not sure if that's the cause, although I am considering installing a thermo on it, and set it up to turn on when the Aircon is on. Still, I imagine the car hasn't had this problem from the factory, so it leads me to think that might just be a bandaid fix that covers some other issue. I'll have to keep looking, I'm considering putting the old fan clutch back on just to see if the problem goes away, might help to prove that's not the problem in any event even if it doesn't fix it...

[mudski]

Hi Potsy,

Thanks for that mate, it's via the factory gauge, which has seemed very consistent prior to this issue. My air con condenser doesn't have a thermo fan, so I'm not sure if that's the cause, although I am considering installing a thermo on it, and set it up to turn on when the Aircon is on. Still, I imagine the car hasn't had this problem from the factory, so it leads me to think that might just be a bandaid fix that covers some other issue. I'll have to keep looking, I'm considering putting the old fan clutch back on just to see if the problem goes away, might help to prove that's not the problem in any event even if it doesn't fix it...

I'm tipping this is the cause. I would have assumed it come out factory with a thermo fan fitted... Crazy not to have a thermo on the condenser IMO. Even if its not the issue.
When your a/c gets warm, how hot is the high pressure hose from the condenser? It should be screaming hot. But it should not be... If you get my drift.
I had similar issues with my a/c, got it regassed, the a/c would be good, then it would cut out and get hot. My a/c guy measured the coolant temp of the a/c gas and it was over double what it was supposed to be. He said all he can do is removed some of the gas to lower the pressure and there for the gas coolant temps will drop and the a/c will kick back it but it may not be as cold. Or, add another thermo to assist the existing one. I got another thermo. Went home removed the grille etc etc and the condenser looked like a sheet of cardboard. Totally blocked from mud and dirt. I spent a bit cleaning it out, fitted the extra thermo anyway, even though I knew i now didn't need too. And the a/c is all good.
So what I'm trying to say I suppose is, because, when your engine is cold, the fan clutch is not running, so there's no extra air flow being drawn through the radiator and condenser. Your motor can handle it but the condenser can't as the a/c coolant is getting to hot, until the engine reaches temp and the clutch fan kicks it to draw the extra air through. Cappish?

The reason why I might not have done it before it the pressure in the a/c system would have been much lower due to less gas so less heat is drawn through the condenser. Now you have a full system it can't. So does this guy who filled the a/c system know how much he needed to put in? Probably a hard question to answer but the guy I used said its a common mistake to a/c people to over fill the system too which will cause this.

Food for thought.

[threedogs]

when putting in Air con gas you put the cylinder on a set of scales and put say 780grams of gas in it.
That should be written in the service manual,
My BIL would get you to sit in the car with the air con on and tell him when it was cold.
He did this to save gas.
But it should be weighed , these days I would think ppl "GUESS" the amount pumped in too much
or too little. Wrong IMO

[Patrol'n]

Thanks for that gents, I just had a chat to a mechanic I know through family, he reckons half way on the factory gauge is perfectly normal / ok for my car, just that it doesn't get anywhere near that warm without the aircon on due to less load, heat etc.
He suggested that I leave the aircon on longer, even if the temp does get to half, and see if it gets back under control by itself.
So i might try that this arvo, and see... (Still paranoid about warping the head though, never had a car of 80"s / 90's vintage before that would run that warm. (Suppose I could get a cooler thermostat)
Where do others temperature gauges sit in summer with the air con going on a hot day? Does half way sound safe enough?
I'm still fitting the thermo fan, going to try and get to auto one or super cheao this arvo after work for a fan. I'm thiking of wiring it to come on automatically with the A/C, has anyone else done this? I'm thinking there may be a relay in the engine bay I could use, rather than the switch wire in the dash? Or should I just wire it to runn all the time? I cant be bothered with a manual switch to operate, had that in cars in the past, PITA if you forget

[the evil twin]

I agree with the opinions above.

It is very unusual not to have a fan on the Condensor.
I haven't owned an RB30 Patrol but my Skyline had one (well two actually after a minor bingle meant the first was now mounted inside the Condensor) so maybe the Patrol did come ex-factory without.

Every other Patrol variant I have seen, owned or worked on has a Condensor Fan and it should come on as soon as you select the A/C on.
I reckon if that was the case you wouldn't see the symptoms you are describing now the system is fully gassed up and that your BIL is right and the gauge would stabilise at/around it's normal spot.

[Patrol'n]

Ok so I've fitted and wired up a thermo fan for the condenser, so if tomorrow is warm I'll get to see if it works, fingers crossed!

[Patrol'n]

Job done, held temp fine. Thanks all who responded! :-)

[mudski]

Great to see.

[liftlid]

Thanks for that gents, I just had a chat to a mechanic I know through family, he reckons half way on the factory gauge is perfectly normal / ok for my car, just that it doesn't get anywhere near that warm without the aircon on due to less load, heat etc. He suggested that I leave the aircon on longer, even if the temp does get to half, and see if it gets back under control by itself. So i might try that this arvo, and see... (Still paranoid about warping the head though, never had a car of 80"s / 90's vintage before that would run that warm. (Suppose I could get a cooler thermostat) Where do others temperature gauges sit in summer with the air con going on a hot day? Does half way sound safe enough? I'm still fitting the thermo fan, going to try and get to auto one or super cheao this arvo after work for a fan. I'm thiking of wiring it to come on automatically with the A/C, has anyone else done this? I'm thinking there may be a relay in the engine bay I could use, rather than the switch wire in the dash? Or should I just wire it to runn all the time? I cant be bothered with a manual switch to operate, had that in cars in the past, PITA if you forget
The thermo is switched on from the receiver dryer when the gas gets hot enough , mine failed a few years ago so it's bridged out and runs whenever the AC is on now.

[Patrol'n]

The thermo is switched on from the receiver dryer when the gas gets hot enough , mine failed a few years ago so it's bridged out and runs whenever the AC is on now.

Yep, I've wired it that way too, its' switch wire to the relay is wired to the switched power for the air con, like yours, mine comes on with the air con, works brilliantly.

[Fozzee63]

Awsome outcome good job