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90ToyAllTrac
11-03-2010, 07:38 PM
Since my engine swap the AC system has been empty. Havent been driving it a lot yet but was told it might be bad to leave it empty in the long run. I will do the coolant upgrade kit but does it hurt the compressor at all to leave it empty while driving it?

Thanks

KM
11-03-2010, 10:37 PM
If you have a belt on the a/c compressor, you're better off having it full, just so it doesn't break from having no oil.

klapa
11-03-2010, 11:23 PM
The compressor itself will not be turning without freon in the system as the pressure switch would prevent the clutch from engaging - so for that aspect there is no danger of damage.

Yet if you mean by "empty" that the system has been opened to the atmosphere and there is currently air - and thus moisture - in the system I would heartily recommend you have the system re-charged with refrigerant or at the very least evacuated to prevent the moisture from fouling the system.

90ToyAllTrac
11-05-2010, 04:23 AM
So where does this "oil" come from? Does that mean just having freon in the system, properly installed?

klapa
11-07-2010, 08:37 PM
No - there are two types of charges - one is with refrigerant only and the other is a mix of oil and refrigerant. You can also get a charge of oil only.

As I said above - there is a pressure switch in the system that will prevent the compressor clutch from engaging - and thus causing the compressor to operate - if you do not have sufficient refrigerant in the system to make some pressure at ambient temperature. So if you are empty of refrigerant the compressor will not turn and lack of oil would not be an issue.

If the system has already been opened you could just disconnect the hose from the compressor and pour about ~2-4 oz. of the correct type of oil in there - yet probably the compressor already has the oil unless it is a new one.

alltracman78
11-08-2010, 12:04 AM
If you want to keep the system in good shape you're best off getting it in working order, having it vaccumed out, and charged with freon/oil.

You want it in working order because it's more likely to stay in good shape if you regularly run it [even in winter, run for a few minutes every couple of weeks]; circulate the oil and freon, keep the moving parts and seals lubricated.

You want to vacuum it out [and fix any leaks] because moisture can cause corrosion and dust/debris can gum/clog stuff up. If you just recharge you don't remove the moisture/debris.
Just for the record, no system is going to be completely leak free, especially an R12 system holding R34a [134a is a smaller molecule]. No matter what the gas inside will eventually seep out. However, this doesn't mean air/moisture/dust can get in. As long as the big stuff is sealed.

Even if the system isn't working, if you recharge it with oil the oil will still move around in the system a little bit, so it's better than nothing.

90ToyAllTrac
11-08-2010, 01:56 AM
well its a low miles JDM setup so im assuming its tip top and I want to keep it that way, so ill probably have it charged soon. Thanks

90ToyAllTrac
11-10-2010, 06:53 PM
The shop just told me that if they install the upgrade kit, that the new valve or whatever sticks up and will not be able to close the hood. They said someone at the dealer either told them this or confirmed it. Sounds retarded to me.

klapa
11-11-2010, 01:45 AM
Sounds kind of retarded to me too!

I went through all this stuff in excruciating detail this last summer. My GT A/C was completely inop and needed a new compressor. The local shop here wanted like $1k to fix it, so I figured either I would do it or just sweat,

My GT already had the "valves" I think you are talking about - the fittings for R-134 instead of the original R-12. These have different threads.

For the high pressure side the fitting is on the dryer - which is located on the driver side of the condenser. For the low pressure side the fitting is on a manifold a little aft of the center of the engine bay on the passenger side. Either way - any shop should have the proper fittings to retrofit your car.

If you would like - I could take photos of my own fittings tomorrow and post them up for you.

Myself - I would not recommend a conversion to R-134 as I don't think it will cool well in your car - as it did not in mine. I would just suck it up and buy some R-12 off eBay if I had it to do all over again.

Just my two cents.

93CelicaConv is the guy around here that really knows all about this A/C stuff.

90ToyAllTrac
11-11-2010, 03:40 AM
They said its the valve that goes on the line that goes over the shock tower is too tall. Yeah, Im gonna figure out another option.

alltracman78
11-11-2010, 04:24 AM
When an AC system is retrofitted to 134a they thread larger fittings on top of the ones that are already on your car. There are threaded caps that screw onto these fittings to keep crap out of the valve inside the fitting.
When it's all installed the new cover on the low pressure line [right by the pwr steering reservoir] sit's really high.
You can try to bend the AC line down a little bit but you might end up breaking a cap [they're plastic] now and then. The shop isn't full of shit [or retarded].

alltracman78
11-11-2010, 04:25 AM
R12 will probably do a better job of cooling, but unless you buy a vacuum pump and vacuum your system out yourself most shops won't service yours.
Though if they do retrofits they should have a machine for R12.

klapa
11-13-2010, 02:38 AM
When an AC system is retrofitted to 134a they thread larger fittings on top of the ones that are already on your car. There are threaded caps that screw onto these fittings to keep crap out of the valve inside the fitting.
When it's all installed the new cover on the low pressure line [right by the pwr steering reservoir] sit's really high.
You can try to bend the AC line down a little bit but you might end up breaking a cap [they're plastic] now and then. The shop isn't full of shit [or retarded].

I take some pics of my GT tomorrow as I need to be working on it anyway. The low side fitting near the shock tower would be the problem as the high side is well below the hood on the dryer - though mine is no problem and has the R134 fittings.


R12 will probably do a better job of cooling, but unless you buy a vacuum pump and vacuum your system out yourself most shops won't service yours.
Though if they do retrofits they should have a machine for R12.

Quite the contrary - most shops would jump at the chance to service an R-12 system if it had R-12 remaining - as they not only charge you to recover the R-12 they then sell the very valuable R-12.

I read up allot on this on may forums and did find that in fact the R-124 is fine for conversion of trucks or cars which have large condensers - but for small sport cars like we have the R-134 will never do a proper job of cooling. Added to that - the R-134 has much higher high side pressures and temperatures and stresses you system sealing much more than R-12.

In addition to the above the oil used for R-134 (PAG oil) is completely incompatible with the oil used for R-12 (mineral oil) - mixing the two will result in your system becoming gummed up and useless in a year or two unless you remove EVERY component - condenser, dryer, evaporator,compressor, and completely drain them of the old oil.

Whatever you do you MUST have the system evacuated completely to remove the moisture - this is a MUST.

alltracman78
11-21-2010, 05:33 AM
Quite the contrary - most shops would jump at the chance to service an R-12 system if it had R-12 remaining - as they not only charge you to recover the R-12 they then sell the very valuable R-12.
If the shop has a machine for R12 they shouldn't have a problem doing it.
If they don't have a machine for R12 they won't touch it because they won't want to contaminate thier machine. R12 might be worth money, but it's worthless mixed with R134a.

So, as I already said, unless a shop has a dedicated machine for R12 they won't want to touch the car.


In addition to the above the oil used for R-134 (PAG oil) is completely incompatible with the oil used for R-12 (mineral oil) - mixing the two will result in your system becoming gummed up and useless in a year or two unless you remove EVERY component - condenser, dryer, evaporator,compressor, and completely drain them of the old oil.

Whatever you do you MUST have the system evacuated completely to remove the moisture - this is a MUST.
Wrong. You obviously don't understand.
When you vaccum out an AC system you theoretically remove all water in the system. Creating a vacuum inside the system causes the moisture [WATER, not oil] to boil out.
You do not and cannot remove all the oil. Even after recovering and vaccuming the entire system it is still coated with oil inside.
If what you said was true every single retrofit would be gummed up. Even if you remove EVERY part from the system and drain it [which doesn't happen], there is still residual oil left inside. The ONLY way to completely remove the oil is to remove all the parts and flush each one out separately. So, every single retro fit that has been done has mixed varying amounts of the two oils together.
Mixing large amounts of the two oils is a bad idea. Small amounts of one added to large[r] amounts of the other is fine. The residue left inside the system won't cause problems.

Please don't tell me I'm wrong when you obviously don't know much about it.

Flux
11-25-2010, 01:33 AM
Im trying to delete my A/C, since my condenser is smashed now.
Is this valve in red, the low pressure valve to drain the system?

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*-Not mine, but its the only pic i could find with the valve in sight...
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http://img718.imageshack.us/img718/3876/cbay11.jpg