1994 Suburban K2500 AC

1998_K1500_Sub

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I removed the old rear TXV. The in-line screen was full of metal. So, I’m obviously replacing it. I can’t seem to locate a new part with the corresponding part number. So, I ordered one from rock auto. UAC part # EX7420PC.

I received the new part in the mail today. The new part does not have the in line screen. If I use the new part (the one without the inline screen), am I going to run into problems?

Your thoughts!?

IMHO having a TXV w/o a screen is like having an orifice tube w/o a screen... any debris that might still be floating around in the system (no matter how well you flushed) could lodge and affect the operation.

I would look for a TXV that has a screen. That's just me. (edit: I looked on RockAuto and I couldn't find one pictured with a screen.)

It's probably poor practice to clean the old TXV, e.g., using Brakleen or other. The mechanism within likely can't be assured to be free of debris, even if the screen is cleared.

Maybe others will weigh-in on this.
 
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Sawlty

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This is my problem. The GM original equipment unit specific to my 94, is nothing like the piece that I removed from the rear AC. Part number on the valve that was removed is #52459601.

GM #52406098 is the recommended replacement part. It has different inlet and outlet lengths AND a totally different thermal wire.
All units that I have seen with rear temperature controls use a straight wire.

Short of calling the Chevy parts desk, I don’t know what to do. I’m probably not going to find an AC specialist at the parts desk.
 

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Sawlty

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I did call the local parts desk. Said part was discontinued many years ago and his system doesn’t list a recommended replacement!

Hmm

I believe I’m going with the aftermarket TXV without the screen.

I’m no expert, but if the nonserviceable screen is clogged up it will cause a restriction and won’t allow the rear system to operate properly. Likewise, if there is no screen and orifice in the TXV is clogged, it will also cause a restriction.

I have both parts in hand. If the “no screen” version gives me fits, I’ll evacuate, replace, and recharge.

Any thoughts on this anyone?

Thanks.
 
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1998_K1500_Sub

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GM #52406098 is the recommended replacement part. It has different inlet and outlet lengths AND a totally different thermal wire.
All units that I have seen with rear temperature controls use a straight wire.

Your model's a 1994, right? It was R-134a from the factory.

RockAuto shows that part (52406098) as applicable from 1996-1999. I might assume this part would function in your R-134a system, but there might have been dimensional changes made to the TXV between 1994 and 1996. The question is whether it will fit.

Note that TXV 52406098 comes with its own aluminum extension pipe. I wonder if that pipe is dimensionally different from that on your 1994 to accommodate the differing size of the later-year's TXV.

The curlicue temperature sensor is, yes, different than the "straight wire", but that TXV comes with an appropriate stainless steel clip that affixes that curlicue nicely to the suction pipe of the evaporator. You should be OK there. I used that style of TXV on my 1998; I'm pretty sure my 1998 came with a curlicue TXV as OE.

RockAuto lists evaporator GM GENUINE 156794 {52464036, 15-6794} for 1994-1999. So, the same size evaporator fits all R-134a years.

So those are my random thoughts. I'm tired and not focused tonight.

FYI, I'll be away through tomorrow and part of Saturday, so I won't be addressing many / any posts on GMT400.
 

1998_K1500_Sub

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I’m no expert, but if the nonserviceable screen is clogged up it will cause a restriction and won’t allow the rear system to operate properly. Likewise, if there is no screen and orifice in the TXV is clogged, it will also cause a restriction.

IMHO it would take less debris to impair the TXV valve (i.e., TXV w/o a screen) than it would to plug the screen.

But that's just my gut feeling.
 

Sawlty

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Your model's a 1994, right? It was R-134a from the factory.

RockAuto shows that part (52406098) as applicable from 1996-1999. I might assume this part would function in your R-134a system, but there might have been dimensional changes made to the TXV between 1994 and 1996. The question is whether it will fit.

Note that TXV 52406098 comes with its own aluminum extension pipe. I wonder if that pipe is dimensionally different from that on your 1994 to accommodate the differing size of the later-year's TXV.

The curlicue temperature sensor is, yes, different than the "straight wire", but that TXV comes with an appropriate stainless steel clip that affixes that curlicue nicely to the suction pipe of the evaporator. You should be OK there. I used that style of TXV on my 1998; I'm pretty sure my 1998 came with a curlicue TXV as OE.

RockAuto lists evaporator GM GENUINE 156794 {52464036, 15-6794} for 1994-1999. So, the same size evaporator fits all R-134a years.

So those are my random thoughts. I'm tired and not focused tonight.

FYI, I'll be away through tomorrow and part of Saturday, so I won't be addressing many / any posts on GMT400.
Yes. 1994.
 

Sawlty

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Yes. The new unit does come with new line. I’ll have to compare them to see if it is different from the original. I hope they are the same because I have been unable to break either of the fittings loose that reside under the rear unit. I’m hoping that I do not have to replace this piece. If I damage it, there is no original replacement. I’ll have to get an aftermarket kit.

Out of curiosity, you say you used a TXV with the curlicue? Does your rear air have temperature control?

Thanks a million for sharing your knowledge. It is greatly appreciated!!
 

Sawlty

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Sifting thru YouTube tonight and ran across this video. Of course it’s for a late model 2500, but still rear air.

I think I’m m going with the no screen version of the TXV.

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Read the blue note in his hand at 0:48!!

Maybe this is a sign from the Suburban Gods!!
 

1998_K1500_Sub

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Out of curiosity, you say you used a TXV with the curlicue? Does your rear air have temperature control?

Thanks a million for sharing your knowledge. It is greatly appreciated!!

Mine has the curlicue.

I do have front and rear heat. The only "temperature control" I have is manual, via a dial control... one dial for the rear, another for the front.
 

1998_K1500_Sub

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Read the blue note in his hand at 0:48!!
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I'm not sure why they make that statement. They didn't back it up with a reason, written on that card.

The OEM put a filter in the system for some reason.
 
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