ac not cold enough - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hittinseedz · 08-21-2009, 03:20 PM

i have a 70 c-10 and the ac blows just cold enough to keep you from sweating. the system has a full charge. where should i start first

**leddzepp** · 08-21-2009, 03:30 PM

Check your heater shutoff valve. If it is not closed when the A/C is on, the heater core will get hot, and work against the A/C.

Ryan Hubbard · 08-21-2009, 03:31 PM

Make sure that your heater valve is working and is cutting off the flow of coolant to the heater core. This will cause the air to be heated.

hittinseedz · 08-21-2009, 03:45 PM

the heater hoses are not hooked up

PanelDeland · 08-21-2009, 04:52 PM

So check to see if the door in the unit is moving all the way and sealing.Another cause could be debris in the ductwork.

**leddzepp** · 08-21-2009, 05:22 PM

Check your cowl fresh air vent (under the hood, passenger side firewall) to make sure it is closed when the A/C is on. I will bet this is your problem. If it is open, it is allowing outside air to mix in, and thus robbing you of cold air. Also check to see that the recirc vent (in the cab on the pass side kick panel) is open when the A/C is on, or you will have a huge loss of airflow

68gmsee · 08-21-2009, 07:10 PM

Couple of questions: Has it worked before? And is it an original A/C truck with the old compressor?

Many years ago, I fought a similar problem on another vehicle. Finally, I got tired of messing with it and bought a new compressor and that took care of the problem.

If your compressor is old it may be that it's just not working effeciently. I'd check all of the things mentioned and then you may have to bite the bullet and go the whole way.

**WorkinLonghorn** · 08-21-2009, 07:15 PM

If all of the above checks out,feel the return line going towards the compressor.It should be very cool (40-50 deg.) . If not you could have an overcharge condition or other problems,such as a stuck expansion valve,restricted screen,or maybe the "power element bulb" is loose in it's fit against the evap.outlet tube.The entire length of the of the bulb must me in tight contact or you will get poor cooling.

BCOWANWHEELS · 08-21-2009, 09:32 PM

You might want to wash out the evaporator in the fiberglass housing under the hood. I,ve seen em real dirty this will not cool as good. Did you measure your refridgerant with a scale when charging system

hittinseedz · 08-21-2009, 10:14 PM

thanks for all the replies. i want be able to check everything until sunday. i will post after that.

HuggerCST · 08-21-2009, 10:30 PM

What are your refrigerant pressures on the high and low side? Is it still R-12?
By the way, Welcome!

hittinseedz · 08-23-2009, 12:25 PM

the recirc vent is open. ac has been converted to 134, lowside has 50 psi, how can i tell if the cowl fresh air vent is closed, any pics would be appreciated, thanks

**leddzepp** · 08-23-2009, 12:29 PM

Quote:

Originally Posted by hittinseedz

the recirc vent is open. ac has been converted to 134, lowside has 50 psi, how can i tell if the cowl fresh air vent is closed, any pics would be appreciated, thanks

Look underneath the cowl on the passenger side. The door is controlled by an actuator on the firewall (you will see the setup when you pop the hood) You might need a flashlight to see it in the cowl.

I am at work, and don't have a camera or pic, but I am sure someone else will post one if needed.

hittinseedz · 08-23-2009, 12:47 PM

when u look at it through the cowl it appears to be flat, when i press the actuator it puts it at 45 degree angle, so with it being flat is this the closed position

**leddzepp** · 08-23-2009, 12:54 PM

Quote:

Originally Posted by hittinseedz

when u look at it through the cowl it appears to be flat, when i press the actuator it puts it at 45 degree angle, so with it being flat is this the closed position

yes, that is correct. it needs to be closed when the A/C is on. check to make sure that is the case with the truck running, and a/c on. if that is functioning properly, you could have some dirt/debris in the evap case housing, or an expansion valve problem as described above.

hittinseedz · 08-23-2009, 01:09 PM

ok F.a.v. is closed with ac on and truck running. what do i need to do to clean evap. also how much is a expansion valve. thanks

08-21-2009, 03:20 PM	#1
hittinseedz Registered User Join Date: Aug 2009 Location: houston tx Posts: 17	ac not cold enough i have a 70 c-10 and the ac blows just cold enough to keep you from sweating. the system has a full charge. where should i start first

08-21-2009, 03:30 PM	#2
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: ac not cold enough Check your heater shutoff valve. If it is not closed when the A/C is on, the heater core will get hot, and work against the A/C. __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man

08-21-2009, 03:31 PM	#3
Ryan Hubbard Registered User Join Date: Aug 2007 Location: Mission Viejo, CA Posts: 288	Re: ac not cold enough Make sure that your heater valve is working and is cutting off the flow of coolant to the heater core. This will cause the air to be heated.

08-21-2009, 03:45 PM	#4
hittinseedz Registered User Join Date: Aug 2009 Location: houston tx Posts: 17	Re: ac not cold enough the heater hoses are not hooked up

08-21-2009, 04:52 PM	#5
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: ac not cold enough So check to see if the door in the unit is moving all the way and sealing.Another cause could be debris in the ductwork. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

08-21-2009, 05:22 PM	#6
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,996	Re: ac not cold enough Check your cowl fresh air vent (under the hood, passenger side firewall) to make sure it is closed when the A/C is on. I will bet this is your problem. If it is open, it is allowing outside air to mix in, and thus robbing you of cold air. Also check to see that the recirc vent (in the cab on the pass side kick panel) is open when the A/C is on, or you will have a huge loss of airflow __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man Last edited by leddzepp; 08-21-2009 at 05:26 PM.

08-21-2009, 07:10 PM	#7
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: ac not cold enough Couple of questions: Has it worked before? And is it an original A/C truck with the old compressor? Many years ago, I fought a similar problem on another vehicle. Finally, I got tired of messing with it and bought a new compressor and that took care of the problem. If your compressor is old it may be that it's just not working effeciently. I'd check all of the things mentioned and then you may have to bite the bullet and go the whole way.

08-21-2009, 07:15 PM	#8
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,861	Re: ac not cold enough If all of the above checks out,feel the return line going towards the compressor.It should be very cool (40-50 deg.) . If not you could have an overcharge condition or other problems,such as a stuck expansion valve,restricted screen,or maybe the "power element bulb" is loose in it's fit against the evap.outlet tube.The entire length of the of the bulb must me in tight contact or you will get poor cooling. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, 2nd owner, Work-Truck supreme. Best $300 I ever spent.

08-21-2009, 09:32 PM	#9
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: ac not cold enough You might want to wash out the evaporator in the fiberglass housing under the hood. I,ve seen em real dirty this will not cool as good. Did you measure your refridgerant with a scale when charging system __________________ I BELIEVE IN JOHN 3:16

08-21-2009, 10:14 PM	#10
hittinseedz Registered User Join Date: Aug 2009 Location: houston tx Posts: 17	Re: ac not cold enough thanks for all the replies. i want be able to check everything until sunday. i will post after that.

08-21-2009, 10:30 PM	#11
HuggerCST Registered User Join Date: Jul 2001 Location: North Louisiana Posts: 4,501	Re: ac not cold enough What are your refrigerant pressures on the high and low side? Is it still R-12? By the way, Welcome! __________________ Wynne 70 CST short fleet Hugger orange & white, 350/350, ps, pb, air, tilt, tach/vac/speedwarning, original buckets, AM/FM, oak bed floor, shoulder belts, 3.5"/5.5" drop, 20" American Racing VN425s. Build thread 53 Chevy shortbed 69 Camaro Click here to subscribe Chevy GMC International Truck Club Louisiana Charter Member http://www.louisianaclassictruckclub.com Last edited by HuggerCST; 08-21-2009 at 10:31 PM.

08-23-2009, 12:25 PM	#12
hittinseedz Registered User Join Date: Aug 2009 Location: houston tx Posts: 17	Re: ac not cold enough the recirc vent is open. ac has been converted to 134, lowside has 50 psi, how can i tell if the cowl fresh air vent is closed, any pics would be appreciated, thanks

08-23-2009, 12:47 PM	#14
hittinseedz Registered User Join Date: Aug 2009 Location: houston tx Posts: 17	Re: ac not cold enough when u look at it through the cowl it appears to be flat, when i press the actuator it puts it at 45 degree angle, so with it being flat is this the closed position

08-23-2009, 01:09 PM	#16
hittinseedz Registered User Join Date: Aug 2009 Location: houston tx Posts: 17	Re: ac not cold enough ok F.a.v. is closed with ac on and truck running. what do i need to do to clean evap. also how much is a expansion valve. thanks



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