Expansion Valve Replacement for '66 Factory A/C

316 Views 15 Replies 6 Participants Last post by RJSalucci, 7 d ago

RJSalucci

Discussion Starter · 12 d ago

Hi,

I have an OEM under-dash evaporator core assembly that was parted off of another '66 many years ago. It's in very nice shape for it's age, and after a good flush and overall cleaning, I plan on installing it on my car. My question pertains to the expansion valve though. Should I just go ahead and replace it with a brand new one just to be on the safe side before installing my evap? I don't have any reason to believe that the original is bad. I just don't know how robust these old valves are with age and use, and am wondering if it's generally just a good practice to replace regardless?

Thanks,
Ryan

1 - 16 of 16 Posts

erials

· #2 · 12 d ago

It’s probably not necessary but I’ve always just replaced the valve anytime I’ve had the system empty for flushing. The valves are pretty cheap insurance and there’s not really a good way to flush them. I’ve always used this one and never had any problems.

More Information for UAC EX6012C

i always install a new receiver dryer and flush the condenser, lines and hoses as well. Refrigerant is way too expensive not to get it all right on the first shot.

Reactions: 1

Rhythim

· #3 · 12 d ago

Technically there's supposed to be a slightly different size orifice in the new TXV for use with 134a, so a new one could potentially perform a little better with that refrigerant. In reality I'm not sure how much of a difference it'll make in terms of vent temp, if any, but it certainly isn't going to hurt anything to change it.

It's more of a concern with the newer systems that use an orifice tube type filter at the evaporator because those can get clogged, but still, can't hurt while you're in there, and they're cheap enough to replace.

Reactions: 1

image98

· #4 · 12 d ago (Edited)

I have restored one 65 and two 66 stock evaporators. I always change out the expansion valve along with the drier. Everything else can be flushed and pressure tested. I converted all three to R134, which required new hoses. I also swapped in high efficiency heat exchangers into two of my under dash evaporators.

Reactions: 1

RJSalucci

Discussion Starter · #5 · 10 d ago

Rhythim said:
Technically there's supposed to be a slightly different size orifice in the new TXV for use with 134a, so a new one could potentially perform a little better with that refrigerant. In reality I'm not sure how much of a difference it'll make in terms of vent temp, if any, but it certainly isn't going to hurt anything to change it.

It's more of a concern with the newer systems that use an orifice tube type filter at the evaporator because those can get clogged, but still, can't hurt while you're in there, and they're cheap enough to replace.

RJSalucci

Discussion Starter · #6 · 10 d ago

image98 said:
I have restored one 65 and two 66 stock evaporators. I always change out the expansion valve along with the drier. Everything else can be flushed and pressure tested. I converted all thee to R134, which required new hoses. I also swapped in high efficiency heat exchangers into two of my under dash evaporators.

erials said:
It’s probably not necessary but I’ve always just replaced the valve anytime I’ve had the system empty for flushing. The valves are pretty cheap insurance and there’s not really a good way to flush them. I’ve always used this one and never had any problems.

More Information for UAC EX6012C

i always install a new receiver dryer and flush the condenser, lines and hoses as well. Refrigerant is way too expensive not to get it all right on the first shot.

erials said:
It’s probably not necessary but I’ve always just replaced the valve anytime I’ve had the system empty for flushing. The valves are pretty cheap insurance and there’s not really a good way to flush them. I’ve always used this one and never had any problems.

More Information for UAC EX6012C

i always install a new receiver dryer and flush the condenser, lines and hoses as well. Refrigerant is way too expensive not to get it all right on the first shot.

Yeah, if for some reason the valve goes once I’ve charged it all up, then that would be a huge bummer. Better to just change it now than regret not doing it later.

erials

· #7 · 10 d ago

When you install the valve, of course make sure you have it connected tightly with a light coating of refrigerant oil on the fittings before you tighten. Most important though is to make sure the coil tube / bulb is strapped correctly to the correct evaporator tube. In case you didn’t know it, the temperature of the pipe the sensing coil /bulb is clamped to is what makes the valve operate.

Also cover it well using the asphalt looking insulation tape.

Reactions: 1

cj428mach

· #8 · 10 d ago

I bought the valve from Rockauto, then added up the efficiency evaporator and all was good. Performs great

Reactions: 1

RJSalucci

Discussion Starter · #9 · 7 d ago (Edited)

Rhythim said:
Technically there's supposed to be a slightly different size orifice in the new TXV for use with 134a, so a new one could potentially perform a little better with that refrigerant. In reality I'm not sure how much of a difference it'll make in terms of vent temp, if any, but it certainly isn't going to hurt anything to change it.

It's more of a concern with the newer systems that use an orifice tube type filter at the evaporator because those can get clogged, but still, can't hurt while you're in there, and they're cheap enough to replace.

I was actually just going to charge it up with R-12 since I still have a lot of it, and since it blows colder anyway. Hopefully the orifice size on the new TXV doesn't get me then if it's sized for R-134a. I'll have to check into that.

RJSalucci

Discussion Starter · #10 · 7 d ago

cj428mach said:
I bought the valve from Rockauto, then added up the efficiency evaporator and all was good. Performs great

RockAuto is an awesome source for parts.

RJSalucci

Discussion Starter · #11 · 7 d ago

erials said:
When you install the valve, of course make sure you have it connected tightly with a light coating of refrigerant oil on the fittings before you tighten. Most important though is to make sure the coil tube / bulb is strapped correctly to the correct evaporator tube. In case you didn’t know it, the temperature of the pipe the sensing coil /bulb is clamped to is what makes the valve operate.

Also cover it well using the asphalt looking insulation tape.

Thanks for the advice. Definitely good information.

RJSalucci

Discussion Starter · #12 · 7 d ago (Edited)

So here's an interesting update. After looking at things a little more closely, I came to realize that what I actually have is a '65 under-dash A/C unit. What had fooled me was the fact that the bezel is painted black (although no camera case texturing). As far as I can tell, there aren't any major differences that would make it incompatible on a '66. The bezel doesn't have the upper lip on it that extends over the top of the fiberglass evap. housing since the '65s had a coin tray in this spot. Unless it's going to look too sloppy not to, I'd rather skip adding the coin tray as I don't want it to be too obvious that I have the wrong year A/C unit on my car (perhaps that's being a bit too picky).

What do you guys think? Is there some reason that I'm not seeing yet why this would actually be a problem? Thanks for all your help so far. I really appreciate the replies I've received on this post so far.

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myfirstcar66

· #13 · 7 d ago

65 type AC was available as a dealer installed option in 1966 and 67. My older son's 66 has dealer installed AC and my younger son's has factory AC. The differences are few but noticeable if you know what to look for.

Reactions: 1

erials

· #14 · 7 d ago

65 model evaporator units had the suction and discharge tube outlets located on the side of the unit while 66 units have the tubes located in the center of the unit. I’ve only worked on 66 models so I’m not sure if the hoses are the same between 65 and 66. This might be something to consider if your evaporator outlets are on the side of the evaporator case.

Reactions: 1

RJSalucci

Discussion Starter · #15 · 7 d ago

myfirstcar66 said:
65 type AC was available as a dealer installed option in 1966 and 67. My older son's 66 has dealer installed AC and my younger son's has factory AC. The differences are few but noticeable if you know what to look for.

Thanks for that tidbit of history there! I definitely did not know that, and makes me feel a little better about having the '65 A/C in there then. I'm a stickler when it comes to keeping everything as historically accurate as possible. So the fact that dealer-installed A/C would've been like that anyway for my car back then is super cool to hear.

Reactions: 1

RJSalucci

Discussion Starter · #16 · 7 d ago

erials said:
65 model evaporator units had the suction and discharge tube outlets located on the side of the unit while 66 units have the tubes located in the center of the unit. I’ve only worked on 66 models so I’m not sure if the hoses are the same between 65 and 66. This might be something to consider if your evaporator outlets are on the side of the evaporator case.

Thanks. that's a really good point, and something that I had not considered. I'll certainly look into that prior to buying my hoses.

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