Air Conditioning Tech Thread.

[CrUZida]

If it cools a lot better when you are moving, then airflow is your issue.
You need bigger fans.

[matty12]

theres many issues that cold cause that issue, air flow, worn compressor and also lowish gas charge can also do it. Unfortunatly to diagnose the issue you need gauges on it.

[TERRA Operative]

It is all stock except for the thicker radiator behind the condenser. The fans are stock, so I'll double check the AC fan is running.
My old Levin was fine, which is what was making me think it might be a gas issue.

It does get cold when moving, bit only cool when stationary.

[matty12]

When its idling is coolish pour some water over the entire condesor and see if that makes it any better

[TERRA Operative]

I'll give it a go this weekend, I'll also check all the other obvious things I can think of.

I've already cleaned the evaporator with some spray stuff and I recently installed a new fan as mine was a bit dodgy (I broke the original one when I dropped it while cleaning it, then chose the dodgy fan of the two I had first time around) so the airflow across the coil is fine now.

[dnegative]

Don't use compressed air, when mixed with oil it can cause an explosion, just like how you don't put oil on the threads of an oxy set.

Air compressor is set at 100psi so even if I dumped all of that in, its not enough to cause problems. Biggest issue would be moisture so nitrogen would be the perfect thing to use, dont think I have fittings to go from the regulator to whatever the fill valve uses though Might be a good idea to get one made though.

Machine at work is getting re-gassed tomorrow so I'll park the car next to it and my auto elec mate can do two for the price of one. Hasn't been able to knock the bottle off from his workshop so this is good timing.

[Z2TT]

Plan of attack on that Levin if you want to make it cool better

- Do your fans come on as soon as you Turn the A/C On? If not Bridge or Cut (Depending on car) the Wires on the pressure switch to make the fans run all the time and this will make it cool better.

- Regas will help and check for leaks before Regas aswell, if some refrigerant has leaked out this will contribute to performance decrease

- Switch to Hychill refrigerant and New Reciever/Drier before Regas.

- Make sure you are using Recycle mode and Not Fresh.

- Expansion Valve can be faulty and this can also cause problems a new one can help in some cases.

- Check that heater tap is not leaking, this will decrease a/c performance.

When A/C Is running touch the Discharge line off the Compressor and it should be very hot, if not the compressor output may be weak but there is no definitive way of testing it's flow that I know of,
anybody know any rule of thumb?

[maccac__1590]

just watch its not the hi/lo compressor cut out switch^^

[TERRA Operative]

Plan of attack on that Levin if you want to make it cool better

- Do your fans come on as soon as you Turn the A/C On? If not Bridge or Cut (Depending on car) the Wires on the pressure switch to make the fans run all the time and this will make it cool better.

- Regas will help and check for leaks before Regas aswell, if some refrigerant has leaked out this will contribute to performance decrease

- Switch to Hychill refrigerant and New Reciever/Drier before Regas.

- Make sure you are using Recycle mode and Not Fresh.

- Expansion Valve can be faulty and this can also cause problems a new one can help in some cases.

- Check that heater tap is not leaking, this will decrease a/c performance.

When A/C Is running touch the Discharge line off the Compressor and it should be very hot, if not the compressor output may be weak but there is no definitive way of testing it's flow that I know of,
anybody know any rule of thumb?

Just had a quick look.

- Yep, fan comes on straight away.

- I'm thinking if I do regas, I'll try out the Hychill stuff.

- Yeah, it is cooler on recirc. I use fresh when the cabin is hot (outside air is cooler) then switch to recirc.

- I'll try this as a last resort. It means pulling the dash out to get the aircon ducts apart.

- I'll check this too, but there is also a flap in the duct work so the air completely bypasses the heater core when it's set to cool anyway.

All the pipes get hot and cold as they should within 30 seconds of turning it on, so it seems like it's doing its thing.
It may be to spec, and it's just me being pedantic, but I reckon Hychill will help. I assume it's safe to use in an R134a system (well a stock system built in 1993 at least)?

Anyone know where I can get this stuff in Brisbane?

[dnegative]

Put a thermometer in the vent and see how cold it is?
Call your local Bursons as they are a distributor, they should be able to put you onto someone who does hychill.

[matty12]

Hychill won't make your a/c any colder, the output temp is controled by the thermosister it will still cut out at 6c or what ever whether you run r12, r134a lpg or any other gas you could use. It may be cheaper if your system is on old r12. Beware but probably won't be of any concern to you, no OE manufacturer will warranty any new compressor on anything but the gas its designed to run one, the are concerns of hychill/er12/ hydrocarbon gas cooking comps but I can see why people use it.

[Z2TT]

That depends IF the temperature is already reaching the temperature that the thermostat is pre-set to cycle at or that the Climate Control unit is set to cut out the compressor at. Hychill/Hydrocarbons being a more efficient refrigerant it makes sense why it will make your A/C blow colder and reach thermostatic cutout quicker, If the car doesn't have any underlying problems that bottleneck the performance of the system it will make it perform better.

Those concerns of Hychill/Hydrocarbons cooking compressors is propaganda and nobody has proven it happens because they cant. A certain organization in Queensland came up with these lies in a newsletter where they put in big bold letters, stating that apparently even Denso themselves put out this info, it was later found that the person who said this at Denso was totally discredited for his claims by the company. Never the less, they did not care to edit that newsletter or release a statement to clear up the wrong information. Because of these incorrect statements with no evidence to back them up, the Internet and forums are filled with hearsay and scare claims of failed compressors and I bet 95% of these people have not done any tests or research.

One of the main reasonings that was put behind this myth of cooking compressors is that apparently Hydrocarbons have poor oil return because they use 1/3 of the Charge by WEIGHT of R134a, the fact is that 1 Liter (Talking in VOLUME) of R134a weighs much more than 1 Liter of Hychill, which is why pretty much a similar amount of Hychill by volume goes in the system in reality, it just happens to weigh much less. The same concept goes if I had a garbage can which to fill up takes 20kg of Concrete, but only 1kg of Hay yet the same volume is used to fill it up.

I have ran Hychill in my own cars Nissan Pulsar, VS Commodore, Toyota Soarer 1G-GTE and 1JZ-GTE, Celsior, Falcon and spanning through Diesel Kiki, Zexel, Denso, Sanden compressor brands and 6 different Compressors overall. In many years none have failed due to the refrigerant that was in it and no Seal Leakages. I did a Check from time to time and all the compressors when taken out had a good amount of oil in. 2 of these compressors I ended up taking apart to inspect the internals for any wear. The oil was clean and all surfaces were in good condition.

Some of the claims that come of compressor failures caused by HC's are when a car comes into a workshop with a low refrigerant charge due to a leak causing refrigerant (and oil of unknown amount) to escape. The shop then fixes the leak (sometimes not) and then performs a recharge with Hychill, by this age the compressor is low on oil and had worn out from previously running with low oil charge. Once the compressor fails Hydrocarbons are to blame.... never mind the fact that the car had been leaking oil to begin with and had done some 272,000 odd KM's already. Other times with many cars the compressor has not turned on for years, which causes a shaft seal leakage and this is where people jump to conclusions.

The next claim is that Hychill should not be used as the system was not designed for it, and with that logic we should not be using 98RON fuel in cars that call for 91 or any aftermarket type of Brake pad compound that performs better and stops faster, than factory OEM pads.
Some older cars that had less efficient serpentine flow condensers, when retrofitted to R134a would often perform sub standard especially on 35+ Degree ambient days where they would normally work great with R12,
and with Hychill too, so if anything R134a in many cases is a refrigerant that the system was not designed to work on even after retrofit.

Hychill has lower head pressures in lots of cases than R134a, is more efficient and very miscible with oil and does not react with moisture or oil present to form byproducts so there is no reason why it would cause A/C Compressor failures. In 20 Years of history of HC Use in Cars, nobody has put toward any logical explanation or made a statement to the ACCC proving this. In the case of the people that put these lies out in a newsletter for millions of people to read, when asked to make a statement under oath, they went silent.



Your vent temperature are going to change day to day, with fan speed and recycle/fresh mode, so what may appear not to be good enough might be OK.

With both front doors open and windows down, put your car on the 2nd Lowest fan speed from the fastest and hold the revs at about 1500rpm, and on Recycle Mode, What does the Vent temp settle at?
And also what was the ambient temperature and also humidity of that day so we can get some Idea.

In Queensland, hydrocarbon refrigerant is not allowed to be installed in A/C Systems.

[allencr]

Don't they have a sight gauge on the hi line or dryer/accumulator any more? It's always the FIRST thing to look at!

[TERRA Operative]

Your vent temperature are going to change day to day, with fan speed and recycle/fresh mode, so what may appear not to be good enough might be OK.

With both front doors open and windows down, put your car on the 2nd Lowest fan speed from the fastest and hold the revs at about 1500rpm, and on Recycle Mode, What does the Vent temp settle at?
And also what was the ambient temperature and also humidity of that day so we can get some Idea.

In Queensland, hydrocarbon refrigerant is not allowed to be installed in A/C Systems.

I'll get some gear and give it a test (my bro is an engineer for commercial HVAC).
Getting it gassed with Hychill is easy. A 3 hour drive to northern NSW will have it sorted.


Anyone know an aircon place in Byron Bay that will refill with this stuff???

[matty12]

Don't they have a sight gauge on the hi line or dryer/accumulator any more? It's always the FIRST thing to look at!

Sight glass is not realy a reliable thing on r134a unless its a later model system using a sub cool condensor which then its partly charged by using the sight glass. Terra's being a 93 coluld be on either from th factory.

Z2TT, it realy depends on the system on whether one gas is going to work over the other. Since holdens are my bread and butter I'll use those as example(although it will all be japlish to most guys here). Old r12 system(70's) use realy inefficent condensors and evap and run low suction pressure to make them work, in that case the r134a could possible not work but also alot of the parts or old and not available anymore so updating to new designs are generally required anyway. VN and VP were on the change over but used the same style of heat exchangers and both work fine, infact the vs's use the same style of serpinetine evap. Ive never had issues with changing them to 134a. Late model VT onwards i would be (but haven't tried) concerned with using a colder gas than 134a, they run so close to frezzing that running a gas that was colder at the same pressure would more than likey freeze the evap. They run around 28psi which is zero degree gas temp, you will in the workshop get 2 degrees out of the vent . Ive had them with failed control valves and the suction will drop to 25 psi and they freeze.

I havent used a hydrocarbon gas since the late 90's early 00's, we used to use FR12 which was the "gun" back then. We had systems that also would not operate on that stuff when retrofit to it from r12, bung in r134a in it worked straight away so nothing a perfect fix for all. As i dont use and therefore have never go into any depth with but there was issue with blends as the would evaporate at different rate and seperate and not work. It was describe to me by pouring two differnt liquids down a hot widscreen one would have evaporatded before it got to the bottom the other would have not.