OEM AC question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

36chevy · Yesterday, 05:26 PM

I live in Florida so it gets very hot here and my square is my dailey. I have the orginal AC but running a 5.3 from 2002 siverrado using the 2002 comressor and orginal clutch fan. In the morming or if its raining the AC is very cold. As soon as a get in any traffic the temp starts raising up to 79 degrees which is not comfortable.

Question is if I go electric will the increased cfm cool better and will that help with my ac problem. Also would going with an aluminum radaiter change anything.

Thank you in Advance
Jesse

**hatzie** · Yesterday, 07:51 PM

Electric fans will make it worse.
If the fan clutch is getting weak replace it.
Make sure you have the fan housing in place so the fan draws all of its' air through the cooling pack.
The cooling pack used to have waxed cardboard wings make sure the fan sucks air through the condenser and radiator.

If you have too much oil and any mineral oil floating around in the system it'll negatively affect your cooling.
Did you flush the hoses, evaporator, and condenser? The dryer is loaded with oil so you have to change it.

The R12 orifice valve is too large. It'll work with R134a but it won't cool as well. The Corvette guys use the Ford blue orifice valve.

If your refrigerant charge is too low the evaporator will freeze up. I recently posted a method to charge an R12 system with another refrigerant and not have too much or too little refrigerant be it Hydrocarbon or R134a or HFC152 or ...
https://www.67-72chevytrucks.com/vbo...1&postcount=10

Dead Parrot · Today, 07:50 AM

Other things to check:
Make sure the heat/cold flapper is fully shut. Doesn't take much slop to let a lot of heat escape into the AC side. The heater core is normally hot all the time so the flapper adjustment is important. It is behind the glove box.
Is the vacuum operated door on the passenger side working? That is the one that lets the recirculate feature work. Reusing the already cooled and dried air from the cab helps with cooling. It should be open when you have the AC on "Max AC" or similar. Labeling varies for different years.
Probably a silly question but when the engine swap happened, did the vacuum for the cab controls get connected, including the vacuum ball?

36chevy · Today, 11:32 AM

Very good points. I did change all accessable parts. Fan clutch ,Dryer, orifcae tube, evap flush.

It never occured to me that these systems are made for R12. I replaced the oriface tube with oem part number. Iam going to start with checking the flapper this weekend.

Yes I did remove the vaccume ball.

ALso maybe there is a way to direct more air from the shroud.

Yesterday, 05:26 PM	#1
36chevy Registered User Join Date: Aug 2011 Location: Miami Florida Posts: 57	OEM AC question I live in Florida so it gets very hot here and my square is my dailey. I have the orginal AC but running a 5.3 from 2002 siverrado using the 2002 comressor and orginal clutch fan. In the morming or if its raining the AC is very cold. As soon as a get in any traffic the temp starts raising up to 79 degrees which is not comfortable. Question is if I go electric will the increased cfm cool better and will that help with my ac problem. Also would going with an aluminum radaiter change anything. Thank you in Advance Jesse

Yesterday, 07:51 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,971	Re: OEM AC question Electric fans will make it worse. If the fan clutch is getting weak replace it. Make sure you have the fan housing in place so the fan draws all of its' air through the cooling pack. The cooling pack used to have waxed cardboard wings make sure the fan sucks air through the condenser and radiator. If you have too much oil and any mineral oil floating around in the system it'll negatively affect your cooling. Did you flush the hoses, evaporator, and condenser? The dryer is loaded with oil so you have to change it. The R12 orifice valve is too large. It'll work with R134a but it won't cool as well. The Corvette guys use the Ford blue orifice valve. If your refrigerant charge is too low the evaporator will freeze up. I recently posted a method to charge an R12 system with another refrigerant and not have too much or too little refrigerant be it Hydrocarbon or R134a or HFC152 or ... https://www.67-72chevytrucks.com/vbo...1&postcount=10 __________________ 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.

Today, 07:50 AM	#3
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,573	Re: OEM AC question Other things to check: Make sure the heat/cold flapper is fully shut. Doesn't take much slop to let a lot of heat escape into the AC side. The heater core is normally hot all the time so the flapper adjustment is important. It is behind the glove box. Is the vacuum operated door on the passenger side working? That is the one that lets the recirculate feature work. Reusing the already cooled and dried air from the cab helps with cooling. It should be open when you have the AC on "Max AC" or similar. Labeling varies for different years. Probably a silly question but when the engine swap happened, did the vacuum for the cab controls get connected, including the vacuum ball?

Today, 11:32 AM	#4
36chevy Registered User Join Date: Aug 2011 Location: Miami Florida Posts: 57	Re: OEM AC question Very good points. I did change all accessable parts. Fan clutch ,Dryer, orifcae tube, evap flush. It never occured to me that these systems are made for R12. I replaced the oriface tube with oem part number. Iam going to start with checking the flapper this weekend. Yes I did remove the vaccume ball. ALso maybe there is a way to direct more air from the shroud.



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