AC overhaul - Compressor upgrade? Condensor?

I just Ordered the Small Pulley 210cc four seasons p/n 88947. I guess I need to grab a smaller serpentine belt too.

I have Several Condensors on the way so I can try out fitment.

OSC 4721
OSC 4544
OSC 4295

The Condensor currently on the suburban is a DENSO 4770865

I have recently read siccussion on Serpentine versus parallel flow condensors. The OSC lists all three above as serpentine. The Denso does not specify. Can you tell just by looking? Is a parallel flow really that much better than a Serpentine?

BowhunterBrown said:

I just Ordered the Small Pulley 210cc four seasons p/n 88947. I guess I need to grab a smaller serpentine belt too.

I have Several Condensors on the way so I can try out fitment.

OSC 4721
OSC 4544
OSC 4295

The Condensor currently on the suburban is a DENSO 4770865

I have recently read siccussion on Serpentine versus parallel flow condensors. The OSC lists all three above as serpentine. The Denso does not specify. Can you tell just by looking. Is a parallel flow really that much better than a Serpentine?

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Parallel flow really is that much better. The parallel flows have a kind of round manifold on each end. The better ones are microtube parallel flow and they are about 3/4" thick. The 2 OSC 4721s I have ordered have been microtube parallel flow.

This is a microtube parallel flow. When you look at the round manifolds on the end, you can tell where plugs were welded to them internally. There are about 5-6 tubes per pass and it is IIRC this one is a 5 pass.



Here is an internal diagram from Classic Auto Air.



When I was setting up the 1987 I was actually hunting an even more efficient subcooling design with a receiver dryer tank on the end, but I could not find one with suitable dimensions and R12 SAE threaded connections. They were all the later style o'ring flange with a retaining bolt.

I wish the aftermarket would wake up and make a larger version of this condeners. It is unfortunately only 12" x 21". This unit is a microtube parallel flow subcooling design with a built in liquid tank receiver dryer. Seperating the gas from the liquid and further cooling the liquid refrigerant by the last pass provides a noticeable efficiency increase by ensuring the expansion device is only getting liquid refrigerant to expand into cool atomized boiling liquid. FWIW if I were manufacturing condensers this would be the only way I built one for any application. The added desicant would also effectively double the moisture handling capability of the system.

L31MaxExpress said:

I wish the aftermarket would wake up and make a larger version of this condeners. It is unfortunately only 12" x 21". This unit is a microtube parallel flow subcooling design with a built in liquid tank receiver dryer. Seperating the gas from the liquid and further cooling the liquid refrigerant by the last pass provides a noticeable efficiency increase by ensuring the expansion device is only getting liquid refrigerant to expand into cool atomized boiling liquid.

Click to expand...

Thanks for explaining that design. I've seen that style on some Toyotas we own and wondered. I didn't realize the tank on the end served as gas-liquid separator to feed liquid into the last pass.

1998_K1500_Sub said:

Thanks for explaining that design. I've seen that style on some Toyotas we own and wondered. I didn't realize the tank on the end served as gas-liquid separator to feed liquid into the last pass.

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Nissan uses the same design and they work great. The condenser on the 2011 Pathfinder and the 2019 Titan are huge compared to some other vehicles.

The Pathfinder has a 25" x 21" subcooling parallel flow condenser and both an electric puller fan and clutch fan. It has always cooled well.

The 2019 Titan has the coldest factory a/c system I have ever witnessed. It will cool mid 30s at idle on a 110F day. EV fan clutch, large clutch fan, subcooling style microtube parallel flow condenser that has a 31.5" x 25" core, and it is an expansion valve H-block setup with R1234YF. People claim the R1234YF does not cool as well as even R134a, but that factory Nissan system cools better than several properly functioning R12 systems I have worked on over the years. I find myself knocking off recirculation and warming the temperature blend knob after a few miles.

L31MaxExpress said:

I wish the aftermarket would wake up and make a larger version of this condeners. It is unfortunately only 12" x 21". This unit is a microtube parallel flow subcooling design with a built in liquid tank receiver dryer. Seperating the gas from the liquid and further cooling the liquid refrigerant by the last pass provides a noticeable efficiency increase by ensuring the expansion device is only getting liquid refrigerant to expand into cool atomized boiling liquid. FWIW if I were manufacturing condensers this would be the only way I built one for any application. The added desicant would also effectively double the moisture handling capability of the system.

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Click to expand...

Thanks for the great info. I went out and checked a spare Denso condensor I have ( damaged in shipping) and it is definitely serpentine. Same one as on the suburban right now. So I imagine I will experience some noticeable gains in chill out factor when I get this larger under driven compressor on combined with a larger parallel flow condensor .

It's odd the OSC parts description says serpentine, but the product image looks like parallel flow. I will see when they show up on the doorstep.

High Side Port

On another note, I will be replacing the high side port this next go around. I did not replace it with this last winters overhaul (didn't realize you could remove it) and I suspect it might have tiniest of leaks. I can just barely hear a hiss of pressure when I remove plastic cap.

My question is do I install GM part with black rubber ball valve, or do I install the Dorman part with standard schrader valve?

Note, I even picked up the proper socket for the job. Mastercool 98234

LOW SIDE PORT

Just thought I would ad some helpful info for those come across this thread, instead of just asking questions.

I had a pretty good leak out of low side port. You could see and hear the leak, which I did not catch the first or second round of evacuation refill. The thing with a leaky port is that it is easily missed with a simple vacuum leak test.

The good news is that I learned you don't have to evacuate the system to replace the shrader valve. This nifty tool allows you to replace valve without loosing refrigerant.

BowhunterBrown said:

My question is do I install GM part with black rubber ball valve, or do I install the Dorman part with standard schrader valve?

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I didn't know they made such a thing

The GM parts are inexpensive, I think I last paid $6 for one. The Dorman w/ replaceable valve may be more reliable (?) and easier to service, when/if service is necessary. Read on...

BowhunterBrown said:

The good news is that I learned you don't have to evacuate the system to replace the shrader valve. This nifty tool allows you to replace valve without loosing refrigerant.

Click to expand...

I wonder if that tool would work on the replacement high-side service fitting that you showed in the prior post.

My take: Keep the service fittings capped when not in use and inspect/clean the service fittings before making connections. Dirt that may get lodged in the valve (or in the refrigerant for that matter) will not be your friend. Tight caps on the fittings provide another barrier to leakage.

BowhunterBrown said:

Thanks for the great info. I went out and checked a spare Denso condensor I have ( damaged in shipping) and it is definitely serpentine. Same one as on the suburban right now. So imagine I will experience some noticeable gains in chill out factor when I get this larger under driven compressor on combined with a larger parallel flow condensor .

It's odd the OSC parts description says serpentine, but the product image looks like parallel flow. I will see when they show up on the doorstep.

Click to expand...

That one is a serpentine model. The 4721s I have received are exactly like the Rock Auto stock image. Parallel flow 34" wide core. With supply chain issues, who knows what they are shipping now. They are selling the same condenser made wrong everywhere for the 80s gas G-vans and a actual tube and fin style for the diesels. That is why I retrofitted a Peterbilt application replacement parallel flow into it.

This was the "Verified Fit" stupidity I ran across on the G-Van. Replacement parts have become a bad joke now. I communicated with Spectra, Agility and Four Seasons and nobody followed through with the issue.