Air Conditioning Tech Thread.

[mick08]

Yeah its actually a smaller 'extracab', i did have the dualcab when i signed up but thats gone now, and yes the lines i got are 1/2inch & 13/32 or 10mm, will post up those dimensions on monday night, thanks again,MICK

[CrUZida]

....Or is because your system works great when you are driving but struggles when stationary? If that is the case you will proberly find you have a combination of two problems:
....
2. Engine not being reved so not circulating enough gas to remove the neccesary heat. (Ineffeicent Compressor)....

I can vouch for this.
Pretty much every car I've done a 1UZ conversion on, when the system was regassed the temperature of the aircon dropped significantly.
Given that the only thing to have changed is the compressor, it has to be the cause.

Previous engines were 5ME, 5MGE, 1GGZE, and 7MGTE.
In all cases the 1UZ compressor was better.

Moral of the story, if you want cooler aircon, get a newer compressor.

[Z2TT]

No problems I got no worries with discussing all things A/C, could rename it to the A/C Thread as these subjects aren't talked about often.

Cruzida, maybe it could just be those cars were low on gas to begin with, and just needed a regas? Or did you previously try it with bad results?

But you might be righ, the 1uz's (in LS400) maybe Soarer too, had the Denso 10PA20C, largest displacement of the 10PA series so I'm not surprised it made an improvement.

On the subject of putting larger condenser in, remember your increasing your systems total internal volume, so remember you might need slightly more gas in to get peak performance, or gas upto recommended amount and then slowly add refrigerant until you achieve good pressures on the gauges.

Rhyno :

Firewall, I'm meaning to put a plug in there, i forgot to put mine back when fixing my leaks,

Pressures I forgot, was a while ago but I will gas it up soon and check the pressures.

Compressor - was a second hand one, my Soarer has a TXV System so most of the debris get caught in the receiver/drier, found lots of alloy shavings in receiver, and well condenser would be dirty to a certain extent, probably a coat of sludge on it, as the high side outlet port was sludge covered after compressor failure. Other lines from reciever onwards are clean as can be, so pretty much my condenser is dirty inside.

Leaks - Replacement compressor is leaking, 3 months until all gas leaks out, that being said I was basing the performance of when I had it freshly gassed, might get a new denso compressor body and bolt my clutch/pulley to it and interface plate, Ashdown/Ingram sell a brand that do Denso copies/replacements, might look into that.

Line Insulation - Will see what stuff is avaliable. Also the discharge line has a thick foam layer around it, no idea why it serves no purpose as it clearly cant abrade or foul on anything, might remove this, no extreme heat source like exhaust manifold around there either. Might head down to Bunnings surely they will have something.

Condenser - For external cleaning, will see what places like Actrol have, but I'm looking to see what solvents can be used safely to flush internally, something that does not leave a residue behind would be suitable. I had a spare condenser that was mangled, don't remember there being any internal fins I might be wrong.

Fan - I don't mind running it constant, Soarer loves to slurp petrol already so why the hell not.

Pictures - Will get some of Current fan setup, It's a factory one, I will get pics of it's placement, only creates a bit of suction when it's on as it's all the way behind the radiator, plus small fan too. Also will get pics of where the Intercooler is.

[matty12]

most of the 90's toyo stuff still used serpintine condensors. Parrallel flow have two "tanks" and mulitple tubes that run from either tank. Im thinking, and without actually seeing what you have would of thought use would be a serpentine condensor. They are esentially one long tube.

We pay a small fortune for "A/C flush" to flush commodores systems out as the oil level on those is critical, it smells exactlly like shellite, which when used leaves no reside.

[Z2TT]

Why do you use "A/C Flush" in quotes?

Why is the oil level critical on commodores (Any series in particular), do they have bad oil return to the compressor so always need the correct amount of oil in them or some other issue?

Thanks

[CrUZida]

most of the 90's toyo stuff still used serpintine condensors.

You sure dude?
More of the 80's stuff I've played with has been parallel.

[matty12]

my ls400 is, 80 series cruiser is, hilux Ln106, corolla up to ae112, wide body camry sxv20 etc.



They went from those to sub cool parrallel flow condensors for most models.
100 series crusier. yaris, Prado, zze122 corolla, vzn/rzn hilux etc.




Like i said im sure the expensive "a/c flush" is just shellite.
VT onwardsCommodore use a variable displacement pump which has a control valve(similar to a epr) which get oil glugged if theres too much oil in the system which the destrokes tthe pump meaning it doenst pump a thing.

They are a good thing as the compressor doesnt cycle which is great for wear of the pump and emissions etc.

[CrUZida]

Hmmm, maybe I need to look a little closer at mine then

[Z2TT]

matty12, are serpentine flow condensers more efficient than parallel, I'm taking it as the gas has a longer route to take it will keep getting cooled more, or does it not make a difference?

Interesting about the control valve, what is it's function, to control the displacement of the compressor? Are you saying the oil will just block that valve?

Cruzida all the 80's stuff I've seen is Parallel too.

[matty12]

nah the parrallel are more efficient, far closer tube pitch and greater fins per inch to start with.Its quite possible that yours is a parrallel condensor i just havent seen any or really worked on any 80's stuff. Got any pics??

I remember reading some wher though that thers is a pressure drop difference between the two, cant remember exact details and what the results were, will check on monday.You have to remember too that r12 didnt need it too be that effecient compared to R134a and a/c in a vehicle was a treat back then where as everone expect a/c these days to be 100%.

The control valve controls suction pressure to around 28psi which is 0 degress R134a gas temp, if this is maintianed there is no need to turn the compressor of is it wont get any colder than that. It also destrokes the compressor when load comes off, cabin temps get down or its just cold outside. This is a reason why you also cant drop in other gases into this system.Your not supposed to put extra oil into them, they get flooded and cant fuction as they have little holes in them that sample crankcase pressure/suction pressure.

[Rhyno]

Hi again everyone, hope you had a great weekend.

Yeah if you want to remain this thread go for it, we are starting to get away from the thread description...

Z2TT, hmmn if your condensor is dirty inside, then that may be your main problem, besides the lack of air flow from your FMIC and system leak. I just tried googling and searching ebay for a new condensor, nothing popped up, but you may have luck using your chassis code or just trying harder

I would imagine their is no internal fins, this would just create pressure drops in the system. Actrols would be the place to go if you have them locally, and just chat to them about their coil cleaner, AC flush and insulation. Actrol WILL have better insulation than whats available at Bunnings. In regards to whats "AC flush" is made from, at the end of the day if its not shellite and it reacts with something, it will only cost more $$$ and headaches to repair. Just check that the flushing agent you are using is compatabile with the refrigerant you are using.

In regard to the discharge line insulation, looking at the pictures I would assume that insulation is there to prevent it from heating up your suction line. I would reccomend leaving it as the cooler you can keep your suction line the better, and even if you have two bits of insulation touching, the insulation will do a far better job of keeping the hot/cold area's hot/cold respectivly.

There are gains to be had from cooling the liquid line, (line coming from condensor to evap) using the suction line (insulating the two together to achieve sub-cooling).

Z2TT, I reckon the best bet for you mate, is fix that leak first and foremost, that will be having a huge limit on your AC system, like boosting with an empty tank, you have all the right parts to go fast - just none of the important stuff.

While you have the comp out, pull teh condensor out and clean/replace the unit. Use AC flush and coil cleaner, reinstall, change the filter/drier and pressure test, and vac then monitor pressures. May as well clean the radiator and condensor while you have access, to improve air flow/efficency off all the systems, minimising heat being radiated to your condensor.

In conclusion, i think your problem is quite easy to fix, you just have a couple of small issues requiring attention (easier said than done, I know ) but I think that fixing the leak, and cleaning your coils should get you out of trouble, or "hot water"

In regards to the different types of condensor, I have not had much to do with the different types of coils but looking at the design of the two, I would say that the parrell type "looks" more efficent, due to serpintine condensor having its hottest point at the start at the coldest at the end, therefore decreasing the temperture difference/efficency, and the long run of pipework, creating friction (of the gas rubbing on the inside of the pipework). Where as the parrellel runs from left to right, therefore having a greater spread of the hottest part of the condensor achieving greatter efficency. Feel free to shoot up arguments against this!

This is just my opinion from "looking" at the two pics.

Matty 12, interesting you say that the comp in the como's never turns off; is this true for when the system is turned off or malfunctioning? Might explain why those things have such bad fuel econermy.

Kind Regards,

Ryan

[Z2TT]

Hi Guys,

Rhyno - Yes I will try to give some attention to the condenser if I can, first of all I will fix the leak and install the thermo fan, if I'm happy with the performance I'll leave it at that.

Actually I was talking about the discharge line being insulated not the liquid line (I didnt get a picture of my discharge)........ the actual outlet line from my compressor is insulated in a foam about 3-4mm thick, no Idea why it seems to serve no function as it cant abrade on anything.

About the Commodore A/C Turning off, Well it depends which ones, systems were different across the commodores of different gens. on the VS the compressor indeed does shut off once evaporator temperature reaches around 2 degrees or so, most likely controlled by a thermo switch. If in case it's not turning off, either the thermo switch is faulty, or the system is not able to get temps so low to reach thermal cutout.

VT Onwards like mentioned have a valve similar function to an EPR, so that would be able to regulate the suction pressure and also it has a variable displacement compressor.... so that removes the need for clutch cycling.

[dnegative]

I recently got the AC in my AW11 up and running again, used a reman compressor with new orings and dryer. I understand that the original system was designed for R12 and because I've charged it up with R134a its not going to be as cold/efficient.

As is stands, it cools the car sufficiently that driving around in 40c heat should be a somewhat pleasant experience but its not icy cold like other cars (even the old work hilux is freezing). Is this due to system limitations (having to run piping so far), gas choice or something else? I notice that the lines under the car ice up so something gets fucking cold

[Rhyno]

Rhyno - Yes I will try to give some attention to the condenser if I can, first of all I will fix the leak and install the thermo fan, if I'm happy with the performance I'll leave it at that.

Actually I was talking about the discharge line being insulated not the liquid line (I didnt get a picture of my discharge)........ the actual outlet line from my compressor is insulated in a foam about 3-4mm thick, no Idea why it seems to serve no function as it cant abrade on anything.

Hey Z2TT, I was surggesting that the existing fan may be ok, given that your condensor is not struggling to remove heat, due to the heat sinks around it. Just trying to save you $$$ and weight, always a good thing!

In regards to the insulation of the discharge - leave it. Its stopping the heat gettin to the suction line. I was only mentioning subcooling the liquid line, just in case it was helpful

Hey Dnegative - is the condensor mounted at the front? When you installed the new comp did you flush the rest of the system? Did the system get a pressure/vac test?

My gut feeling is that you have one of three problems that will cause your suction line to ice up:

1 Your system is leaking refrigerant, and therefore freezing up the suction line, not the evaporator, as because there is not pressure difference at the TXV, so the refrigerant is only fully evaporating at the suction port (not good, can %^%# compressors real fast, as you are not far off from compressing liquid)

2 Your TXV is malfunctioning and allowing too much refrigerant to pass through the evap.

3 Your evaporator inlet is jammed with gunk, and not getting enough airflow across the coil to adequatly cool the car, and hence icing your evaporator and suction lines.

Any infomation you can give on this will be helpful towards a more accurate diagnosis. Do you have the part number of the comp perhaps? Maybe its more efficent...

Catch you tommorow,

Ryan

[dnegative]

I can only assume it was ice as it was white but it was on one of the hoses coming off the compressor before the insulation started (inch or two), the line at the front near the dryer just gets really cold but doesnt ice up. I didn't do the gassing, auto elec did and he said it was all good. Held vac for 30mins, condenser is at the front.

I just compared mine to an xtrail, mine was very cold but the dirty nissan was icy cold.

3 Your evaporator inlet is jammed with gunk, and not getting enough airflow across the coil to adequatly cool the car, and hence icing your evaporator and suction lines.

That's quite possible, I used to have minimal airflow going across the radiator and condenser due to the JDM plate holder not working for ADM plates and I just stuck the plate smack bang in the middle. Never had issues with the car running hot so I never had any need to change it until 20mins ago when I thought about it. Couldnt see any white frost on the connector after the test but it could of still been there just clear.