I'm back again, and this time I need help with some stuff related to A/C.

First of all, I'm trying to refill the system with R134a. It was still holding a small amount of pressure when I checked the fitting on the condenser, and all the hoses look brand new, so I'm guessing it just hasn't been charged since it was stored ten years ago. Is there a proper procedure for this, or do I just pop an adapter on the condenser fitting and plug an R134a refill can into it? I'd rather the compressor didn't spontaneously explode just because I'm an idiot.

Secondly, I'd like to find a fan switch that turns on at around 200 degrees and has the original electrical connector, as I don't like hacking up wiring if it isn't necessary. I'd also like to not cook the motor with the original switch; I've just been using the A/C switch to turn the fan on since I bought the car but that's getting annoying.

 

First of all, you need to know what's in the system already. R12 or R134A. They take different oils. You should probably replace the receiver/ dryer too, as the original r12 dessicant isn't compatible with 134.

 

R12 oil and R134a refrigerant are incompatible. The oil turns into a waxy substance and blocks everything.

I've written up MULTIPLE times how to do this. Search my userID and the phrase "orifice tube", and you'll find it repeated many times over. Basically it invloves replacing the compressor, accumulator/dryer, orifice tube, EVERY O-ring, and EVERY piece of rubber line; flushing out the metal parts to be re-used (lines and heat exchangers); making SURE the cooling system works properly, especially the radiator fan; cleaning the evaporator of leaves and bugs and whatnot; and how to fill with oil, evacuate, and refill the system afterwards.

I wish the mods would make one of them a sticky, or combine a couple and make one big one. Or better yet, have me write it up all at once, and use that instead of piecing together old posts.

For the fan switch, there's nothing wrong with the original. Worked fine in 1984, works fine today. (the identity of the part, that is; assuming that your particular one "works" of course...) There's no particular reason to replace it with anything else. Nothing is going to "cook" your motor with that one, any more than with any other.

 

Not going to cook the motor? When it turns on at 240 degrees?! The engine's so hot it's misfiring by that point, so yes, I'd say there's something very much wrong with it. Other than that, thanks - it's still got the R-12 sticker on the dryer, so I'll assume it still had R-12 in it. Hopefully I can find someone to refill it with R-12, I don't have the money to replace the entire A/C system right now.

 

:shrug:

Turns on at 230 some-odd degrees. WELL below the boiling point. Worked fine in 1984. No reason it won't work just as well in 2020.

Not going to comment on "misfire"; that sounds like some whole other matter, completely unrelated in any way to running at the correct factory temperature.

Good luck with that. Not "impossible" exactly, but rather unlikely, in 2020. And of course, good luck the next time too, when it all leaks out, from not tearing it down and fixing all the leeeeeeks. After all, there used to be some refrigerant in there; if it's not in there anymore, it went ... somewhere somehow.

 

It misfires when it gets that hot because it's boiling the fuel in the bowl. Same thing happened to my Slant 6 when it got too hot. More of a Washington problem because our gas is awful. And I'd prefer to keep the engine as cool as I can to prevent the oil from sludging up, especially around the edges of the valve covers (which has already started to happen).

 

Update: A/C components are waaaayyy cheaper than I thought they were. New set, including everything you listed as 'needs replacing,' is on the way now. Only thing I couldn't find was a condenser from a decent brand so hopefully mine's in decent shape. Like I said, there was still a little pressure in the system, so I don't think it's been holed.

 

That's probably OK; condensers most often can be cleaned up and re-used. The things that happen to them the most are leaks from punctures like road debris and whatnot, and ones from corrosion. If yours doesn't have either of those it should work fine.

To keep the fuel from boiling in the bowl: most often, it's not the carb that's getting hot; it's the fuel pump. Make sure there's a gasket between the blockoff plate thing and the block, and between the pump and blockoff plate. You can even add an extra in one or both places to help out. Or even go hog-wild: https://www.summitracing.com/parts/ctr-85-000 And of course, BE CERTAIN that the return is working properly; without that, fuel dead-heads in the pump, and can get REAL hot in there. It's critical to keep it circulating.

 

Bold of you to assume the previous owner even hooked the return up!

 

Hey, I would never ***-u-me ANYTHING!!! Which is why I mentioned it.

If s/he didn't, then that's more likely to be the first thing you can do to fix the heat-related problem that will make an impact, rather than mess with the cooling system.

 

I mean, this is the same guy who managed to wire the $20 head unit he bought in with 14 different wire-twisties and the ignition hot wire soldered to the chassis ground, declined replacing the $11 front sway bar links, and replaced the shift cable bushing on the transmission side with balled-up duct tape to save a few cents.

 

Sounds like you're in for a long, interesting ride.

A wonderful example of why "hack on the cooling system" is NOT the right answer for "PO got his p****-pullers into everything and BOTCHED everything he even got close to whether he touched it or not".

Certain parts of these cars work REAL GOOD just like they came from GM. Not ALL of course; you'll get real tired of getting your a$$ whupped at traffic lights by Kia minivans and stuff like that for example; but the cooling system, electrical system, and lots of other things, work JUST FINE in original trim.

 

I did end up finding a switch that turns the fan on at 212, with the OE connector. I do have a Cold Case radiator/dual fan kit that I was planning on putting in after the built 700R4, but I may forego the fan kit and keep the stock shroud (hopefully with a better fan motor). There's currently very little wiring dickery going on in the engine bay and I'd kinda hate to cut it up for no reason.

 

I wouldn't care about the original connector. I installed a fan switch from Painless Wiring that turns on at 195 and off at 185. Uses 2 female spade connectors...

 

I do care, though. Having already owned one project car in which the P.O.s "didn't care," I can safely say that it was an absolute electrical nightmare. Granted, I'd do a better job than they did, but there's no sense in hacking up a harness if there are any other options.

 

Changing the connector on the fan switch wiring is hardly an "electrical nightmare", and if you do it right, nothing would be hacked up. The wiring on my thirdgen is NOT hacked up, and I have a fan switch that doesn't wait until 222 degrees to kick the fan on...

 

Greeting from Boston:
I am following sofakingdom's instructions on my 88 RS Camaro doing all the replacing and flushing with a new AC Delco compressor.
But, I need greater detail in replacing and fitting that little orifice tube. I am not certain I am putting it in deep enough and the top tab may be folding over creating a restriction. Both sides become equal at 90 psi when compressor is not running but the high side does not move up and low side does go down to 40 when compressor is turned on.
Before charging I put about 3 oz of pag 100 into the tube where the orifice tub inserts (also 3 in the new compressor). I'm assuming the oil is not creating a restriction. So, is what is the proper way to fit the orifice tub into the crimped tube.
pmmBoston

 

There's really nothing magical about it. It just kinda pushes down in there. Its O-ring should slide into the line and provide a certain amount of resistance, but nothing irresistible. (assuming of course, that it has a bit of PAG oil on it) There should be maybe around ¼" or so left exposed when done. Not enough to grab with your fingers, but easy to get with needlenose.

If you look down into the line that goes onto it, you'll see that there's nothing in there that will interfere with the "tab" feature. If you look down into the evap input, where it goes into, you'll see that it's a bit larger at the entrance, to accept the tube; then necks down a bit to keep it from going in too far.

If it was blocked, you'd get REAL high pressure on the high side and REAL low on the low side, IMMEDIATELY, when the compressor comes on, and no cooling. It should cycle back off within just a few seconds. If it's not doing that, then it's not blocked.

90psi not running on both sides is about right for a low-mid 80s ambient temp. The pressure will stabilize on both sides at the equilibrium vapor pressure of the refrigerant, and so will vary according to outside temp. The vapor pressure is just a hair higher than the temp in °F, in the range we'd usually be working in.

Pouring oil into the evap isn't a real good idea, but what's done is done. It's better to pour it into the accumulator/dryer. And besides it's much easier. But it'll eventually sort itself out.

Failure to build pressure on the high side at the same time as failure to reduce pressure on the low side can be caused by either lack of restriction by the orifice tube (such as, if it's stuck wide open, or if the O-ring is missing, or the whole thing got left out) or bad compressor.

 

Sofakingdom: Thanks for very prompt reply with the great info. I guess there is no blockage as I do not get real high pressure or real low pressure immediately.
I'm not certain if I am getting any cycling. From 90 psi the low goes down to say 40 when the compressor is on and sort of sits there. The high does creep up but there is not much in terms of cycling. I am also dealing with a very cheap set of snap on r134a adapters and the red one is barely depressing the Schrader valve on the high side. Got great Yellow Jacket manifold gages but the cheapest adapters.
Thanks again.

 

Right, well, looks like I'm waiting until I replace the A/C to do the fan switch, as the drier pretty much HAS to be off to get to the switch. What an idiotic place for a heat-sensitive component with a plastic connector.