AC Condensor Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Nodnarb76 · 05-28-2019, 05:28 PM

When I did my LS swap, I installed a new compressor, receiver dryer, orfice tube, and accumulator. For the past 3 years when my AC is on it will blow cool, then warm a little, then cool etc...

I converted it to R134 already, should I replace the condenser with a parallel flow condenser? I have heard to do that once it is converted to R134.

**hatzie** · 05-28-2019, 07:43 PM

What're your pressures running at what vent and ambient temps?

Did you flush out all the old oil? The old mineral oil left in the system can slosh around and inhibit thermal transfer.

Dead Parrot · 05-29-2019, 12:04 AM

It is normal for the compressor to cycle on and off. Keeps the cold side from freezing up.

Also possible that you have either too much or too little refrigerant. 134 is less tolerant of improper refrigerant amounts compared to R12.

Some systems have a thermostatically controlled on/off anti-freeze switch in addition to the too low and too high pressure switches. If you have one of these, sometimes you can adjust it cooler while still not freezing up the system.

05-28-2019, 05:28 PM	#1
Nodnarb76 Registered User Join Date: May 2013 Location: Mississippi Posts: 501	AC Condensor Question When I did my LS swap, I installed a new compressor, receiver dryer, orfice tube, and accumulator. For the past 3 years when my AC is on it will blow cool, then warm a little, then cool etc... I converted it to R134 already, should I replace the condenser with a parallel flow condenser? I have heard to do that once it is converted to R134. __________________ 1987 R20 Suburban LQ4/4L80e swap: http://67-72chevytrucks.com/vboard/s...d.php?t=693824

05-28-2019, 07:43 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: AC Condensor Question What're your pressures running at what vent and ambient temps? Did you flush out all the old oil? The old mineral oil left in the system can slosh around and inhibit thermal transfer. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

05-29-2019, 12:04 AM	#3
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,611	Re: AC Condensor Question It is normal for the compressor to cycle on and off. Keeps the cold side from freezing up. Also possible that you have either too much or too little refrigerant. 134 is less tolerant of improper refrigerant amounts compared to R12. Some systems have a thermostatically controlled on/off anti-freeze switch in addition to the too low and too high pressure switches. If you have one of these, sometimes you can adjust it cooler while still not freezing up the system.

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