How to rinse off UV die on a leaking car a/c system?

Nedavno rp napisa:

I won't.

Yes I fitted the two speed auxiliary fan. Without a/c I only had one, engine driven fan. Now when I turn a/c on, aux fan starts at low.

Could that be the problem? I doubt it can shift much heat at low speed.

Nedavno rp napisa:

No. It should do exactly that. High speed is activated wit the sensor located in radiator (actually there art both low and high speed sensors in the radiator).

I can understand that for the engine coolant temperature but I can't see how it can be expected to cool the a/c system on low. It needs a lot more air for the a/c than for the engine cooling, at least it does on my car, but that's R134a although regardless of refrigerant it still has to get rid of the same amount of heat.

Nedavno Duncan Wood napisa:

I've done some more tests today.

First, I've sprayed some refrigerant at the temperature sensor of the ice preventing switch, and it turned the compressor off. So it is not broken.

Then I removed trim panel at the side of the evaporator where the expansion valve is, set fan to low, and almost closed all vents to minimize airflow around the evaporator. Waited about five minutes, but no sign of icing at the pipes that are visible at the side of the evaporator.

I know that I might have overcharged the system, I'll try again after bleeding some refrigerant out, when I find some spare time.

I have often found that a little esperimentation with the pressure while watching the evap unit is a good way to get things as cool as possible, you don't actually want it to be icing, so if you get to that stage just add a whiff of gas to bring it above icing and it will be fine, till it loses some gas and starts icing, then you know to top it up again.

Mrcheerful

Nedavno rp napisa:

It blows a lot of air on low too. When it gets on high it makes a lot of noise, and it blows a looot of air. I've been watching some US newsgroups, and I remember reading that with a/c on, and in a slow traffic fan almost newer switches on high.

Nedavno Mrcheerful napisa:

Any ideas on how to bleed some refrigerant, and not oil with it? I tried before, and first only refrigerant comes out, but than oil comes out too.

let it settle for an hour or two or overnight, then SLOWLY let a little gas out, the oil should stay in. while the system is running the oil is being blown around with the gas, but when stopped it should stay on the pipework, slow gas flow should leave it there.

Nedavno Mrcheerful napisa:

I tried this, and I just could not get it to blow below 12 C with the fan speed set to low. If I set it to high, it blows ~16 C. Car was in the garage hole day, ambient temperature was 32 C, engine rpm 2000, recirculation on.

The best bet is to go to square one: empty the system, vacuum it for as long as you can, 4 hours is the recommended time, purge the charging hoses of air and fill the system with the right weight of gas.

But fit a new dryer if you didn't last time.

Nedavno Mrcheerful napisa:

I tried this, and it did not work. So I collected the oil in the bottle, and there was about an inch of oil at the bottom of it.

Strange thing is that when I looked more closely it was like oil and water in it, just it was oil at the bottom, ~3/4", and something else at the top ~1/4". It could be UV die, but I am suspecting that a/c shop might have put in the wrong oil (they did put in r134 in instead of r12). And there might be some mineral oil in the system. What do you think? I checked with the UV light and goggles, and stuff at the top does not glow. What do you think, what is this?

Oh, and another thing. If I shake the bottle bubbles come out of it, like in the soda, and it looks like it comes out of the top layer.

BTW there were some debris at the evaporator, but nothing major. It looks to me like it is clean, no dust, or oil, etc. But I cleaned it anyway.

That sounds more like a leak stop fluid.

I found some spare time to continue work on my a/c, so hire is an update.

For those that did not follow this thread from the biginning, I fitted a/c to my '87 BMW 316 from a wrecked car, and I am trying to make it work properly.

I went to the a/c shop, and they filled the system with wrong refrigerant (R-134a), so I decided to continue work myself.

I fitted the correct refrigerant (R-12), but I could not get it to blow lower than ~15 degrees Celsius.

After helpful suggestions from this group, I decided to pull out the evaporator, and flush the system.

Evaporetot was not dirty (Not too much anyway, air could freely move trough it), but it seems that the a/c shop poured some oil in that was not miscible with the mineral oil that was in the system. When it was out it was like oil on the water.

So I flushed, drained oil from the compressor, poured correct amount of mineral oil, changed the dryer, vacuumed the system and filled with R-12 (at the moment I could not find the scale to measure correct amount of refrigerant, so I filled again until there were no bubbles at the sightglass.

And it now works!

Well, sort of :-) At first I thought that nothing changed, it was blowing ~13 C at idle. But when I drove off, it went down to the 7 C. Now compressor is cycling (and it didn't before), and I had pleasant 24 degrees inside with 32 C out.

It looks that combination of higher revs than idle (~2000), and more air cooling condenser is helping.

Anyway I am happy now, thanks to all who helped.