Dumb question-Will larger condenser improve performance

[Matt-In-AZ]

This is my first question on the forum, and probably a dumb one. In general, will installing an oversize condenser that will hold more R-134 improve the system's performance? The ambient temperatures here that cause issues tend to be over 110 degrees F. My question also applies, maybe, to R1234yf systems.
Thanks from the new guy.

No signature file yet, but I'm in west Phoenix, AZ.

[bohica2xo]

A larger condenser can help some systems. A more efficient one can as well. A lot depends on the vehicle you are talking about.

[Matt-In-AZ]

I have two vehicles in mind.
The first is a 1996 Dodge Diesel Club cab 4x4. It uses R-134 and currently puts out about 45 degree air from the center vent at an ambient 109F, when I have a 12 inch aftermarket electric pusher fan in front of the condenser turned on. The system was completely rebuilt two years ago.

The second is a 2017 Subaru outback that uses R-1234yf. When moving at 35 mph, it puts out 42 degree air from the center vent at an ambient 109F. But when idling at lights or waiting, that creeps up to 60 degrees, then 80 degrees. Also, when on multiple errands, it won't temperatures from the center vent won't drop below 90 F until it gets driven for about 10 minutes at 35 mph.

I suspect that the problem with the Subaru may be something different, since it has been slowly developing. I don't have a manifold gauge set for R-1234yf yet, so I can't comment on pressures.

[bohica2xo]

The Dodge is probably due for a new fan clutch. They wear out, and while the engine does not overheat the rest of the heat exchangers suffer. The fact that you need an added fan kind of points that way.

The Subaru is a little more complicated. First, pull the DTC's It could simply be low on charge, or have other issues

If you see a B1641 or B1642 It may be the refrigerant flow sensor. This in mounted on the compressor, and can be replaced. Subaru does not sell it, and will gladly sell you a $1000 compressor. This is a problem with the TSE14 compressors used on some Toyota cars as well as the Subaru. There are aftermarket sensors available

[Cusser]

Disclaimer: I'm NOT a professional AC mechanic, I'm a retired industrial chemist. But I know some, and have lived in Phoenix 5 decades, but now split my time between Phoenix and Prescott area.

109F ambient is common for summer in Phoenix, today and tomorrow are forecast for 115F, but cooler than the 119F hit several times in July. Parking in sunlight will cause your seats, dashboard, etc., to heat up to like 150F, and that heat must be removed to feel cool.

In general, will installing an oversize condenser that will hold more R-134 improve the system's performance? The ambient temperatures here that cause issues tend to be over 110 degrees F.

Adding a larger condenser so the system could contain additional refrigerant will not improve performance, the amount of liquid refrigerant getting through the expansion valve or orifice tube is metered. I would guess that only if the condenser is not capable of cooling the high pressure refrigerant gas to liquid that such larger condenser would help.

I have two vehicles in mind.
The first is a 1996 Dodge Diesel Club cab 4x4. It uses R-134 and currently puts out about 45 degree air from the center vent at an ambient 109F, when I have a 12 inch aftermarket electric pusher fan in front of the condenser turned on. The system was completely rebuilt two years ago.

This looks to have pretty good performance. 45 degrees from center vent is considered good performance. I do agree about the fan clutch though; I have had to replace the fan clutch in my three small trucks about every six years, replaced all three last year. I did not have any engine cooling issues at that time on any.

The second is a 2017 Subaru outback that uses R-1234yf. When moving at 35 mph, it puts out 42 degree air from the center vent at an ambient 109F. But when idling at lights or waiting, that creeps up to 60 degrees, then 80 degrees. Also, when on multiple errands, it won't temperatures from the center vent won't drop below 90 F until it gets driven for about 10 minutes at 35 mph.

I suspect that the problem with the Subaru may be something different, since it has been slowly developing. I don't have a manifold gauge set for R-1234yf yet, so I can't comment on pressures.

Your 42 degree air from the center vent at an ambient 109F when moving hints to me that your Subaru system is fine when there's sufficient air flow over your condenser, and moving along makes a ram effect through the condenser. But when idling/city that air flow must come from the Subaru's electric fans, so I lean towards an air flow issue over the condenser; tough to cool anything when the air temperature 3 feet above the road is 130F or more !!! Of course make sure there's no insects/debris covering the front of the condenser, but make sure that ALL the electric fans are operational when the AC is switched on. And make sure all the fan shrouding is in place. My daughter lives in Phoenix and has a 2013 Subaru Forester (R134a) and doesn't complain about the AC when she drives around, so I don't think it's an endemic Subaru issue

I'd also visually check that the compressor drive plate (the center section of the compressor) is turning at the same rate as the drive belt and outer rim of the AC clutch (called AC clutch magnetic engagement). Is it possible that the Subaru is low on refrigerant due to typical seepage through the compressor seal since 2017? Yes. But 1234yf is quite expensive, and even if you had 1234yf gauge set, pressures only give a hint at refrigerant amount; the only real way is to have the 1234yf recovered and weighed using a quite-expensive machine.

Since you're in west Phoenix and I'm half-time in NE Phoenix, I cannot suggest a shop near you. But if you don't have an independent ASE-certified shop near you that you like, I would suggest choosing one near you from this Phoenix list, he vets them pretty good:
https://salemboysauto.com/marksalem/bes ... &subType=M


25th Street Automotive
4112 North 25th Street
Phoenix, AZ 85016
Major Cross Streets: 25th Street and Indian School
Hours: M-F 7 am to 5:30 pm
602-955-2637

Action Auto Repair
2618 W Deer Valley Rd
Phoenix, AZ 85027
Major Cross Streets: West of I-17 on the North side of Deer Valley Rd.
Hours: M-F 7am to 5pm
623-582-2982

Blackwell Automotive
15440 N 40th St
Phoenix, AZ 85032
Major Cross Streets: 40th Street and GreenWay
Hours: M-F 7:30am to 6:pm
602-992-5478

Curt's Auto Repair
2222 W Bell Rd
Phoenix, AZ 85023
Major Cross Streets: 1-17 and Bell Rd
Hours: M-F 8:00am - 5:30pm
602-588-2878

Larry Harkers Auto Repair
3845 West Indian School
Phoenix, AZ 85019
Major Cross Streets: 38th Ave and Indian School
Hours: M-F 7:30 am to 5:30 pm
602-278-5558

Martin's Auto Repair
3636 North 16th Street
Phoenix, AZ 85016
Major Cross Streets: 2 blocks south of Indian School Road on 16th Street
Hours: 7:00AM - 5:30PM
602-266-5755

[Tim]

These guys were good and were just around the corner when we had the West Side Facility.

Larry Harkers Auto Repair

[Matt-In-AZ]

I miss your west side facility, by the way. Many years ago, you were able to fab up a hang-on kit for my mom's 1974 AMC Hornet. The car was 20 years old the, and the kit could freeze out the passengers--so to speak.

I had Oscar Munroy make up an immense radiator and the system was great.

[Tim]

My second car was an AMC Hornet after I got the CJ5 taken away from me.

In my defense, what did they think would happen when you give a 16-year-old a Cj5 with a small block Chevy in it?