What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

A/C Charging

bigred88

bigred88

1/2 ton status
Joined
Feb 11, 2008
Posts
738
Reaction score
232
Location
Divide, Colorado
My A/C has been blowing a little warm this summer, so I bought one of those DIY freon/gauge all in one things from Autozone. I had the system converted to r134 3 years ago (the right way- just about everything replaced), and I haven't touched it since- it's never needed recharged. Well, I hooked up the bottle and the gauge to the low side, A/C on max, following the instructions, and the gauge was reading 60psi. It's 105 degrees outside. According to the instructions on the bottle, that means the system is full (well, slightly overfull). According to some websites, the system is overcharged right now, if I'm reading them correctly. But other websites sound like the pressure should be up over 100. How can it be overfilled if I've never opened it up? And if it hasn't lost refrigerant, why would the inside temperature have dropped off slowly, just as if it had been slowly dropping freon?

Honestly, I'm a little confused. What I've read says the low pressure side is constant, regardless of temperature, and the high side changes with temp. But the bottle I bought only hooks up to low side, and it's recommendation does change with temp. Not a lot, but some. I don't know A/C systems at all. I picked up a book a few weeks ago, but haven't gotten very far in, just been too busy. I was gonna do this right and buy manifold gauges and everything, but I'm sick of the heat and don't want to go that far without knowing what I'm doing.

I put a thermometer in the dash vent, and it's blowing about 78*. From what I've been able to figure out, a full and properly functioning system should blow about 40* colder than that.

I'm new to the whole A/C charging thing, so just go ahead and assume you're talking to a moron with any replies. Except, yes, I know all the safety stuff- eye pro, gloves, don't be an idiot... I've got those things down. Thanks for any help or guidance.
 
Thanks for the link. Shows how much I know about A/C, I didn't even know there were different types of condensers.

I just looked at the condenser- I'm sure it could stand to be rinsed off, but it didn't look bad. Now I'm going to try and figure out what kind it is, just to know.
 
if your in that much heat all the time possible best to add a fan to push air over the condensor when low speed or stoped. makes a diffrence
 
Sounds like your head pressure is too high. That will cause the low side to read high and give you warm air.
Get some degreaser or soap and clean the condenser and regular radiator good with a hose.
Just a small amount of grease or bug guts will decrease the cooling ability of the system.
Also check your air flow. If you have a clutch fan, give it the spin test and also look for any oil leakage.
Just because the truck is not running hot, does not mean that your fan is doing its job.

If cleaning it up, and checking the fan does not help, then you may have to take it to a place with full gauges.
If it cools better when running on the highway, then its probably a condenser thing.
You could have a problem with the orifice tube, but they usually stop up, not open up.
Also make sure you do not have a blend door or control problem. It might be letting some air come in through the heater core.
 
Thanks for the replies. I'll go ahead and clean the condenser and radiator, see it it makes a difference. And check the fan clutch.

The temps aren't usually this high, we've just been up over 100 for a week now. Kind of strange, I think. This is only my second summer here, so I don't know, maybe it is normal.
 
not the norm for STL... it's just been hot as hell in the mid west so far this summer...
 
If you use a hose, do not use a nozzle. High pressure will probably bend the fins and worsen the airflow. Just use a hose without any attachments.
 
Yep, it may just be that everything is working as well as it can. If you don't have the parallel type condenser, it might just be that the outside temp has reached the point where it cannot dump the heat fast enough.

Its possible that it has been marginal all the time, but just is not up to the requirements when it gets really hot.
Air conditioning systems are just heat pumps.
They move the heat out of the passenger compartment and dump it to the outside air.
If they cannot get rid of it, then you get warm air coming back.
 
Well, mine's definitely not a serpentine or parallel flow. I'm having trouble finding a good description or picture of a piccolo, or how to tell one apart from a tube and fin, but mine's definitely one of those two. So maybe the r134 conversion wasn't done completely right... oh well. That's what happens when you don't know your stuff and just trust someone else to do it right.

It may be that it's just always been marginal. I had it done when I was in Colorado, and barely ever needed it there, and then I didn't need it much in California, either. The last time I was in this kind of heat I was driving through Arizona, Nevada, and southern California and my blower motor went out, so it's still better than 110* with no AC.
 
Hottest summer i remember here in the STL, anyways at around 100 your truck should still blow colder than 78. If cleaning the condenser doesnt work, my dads supercharged Sub had a similar problem and it was his mech fan clutch. He put a heavy duty one on it and a elec aux fan also and it works fine now. Now if it doesnt cool off at highway speeds where your mech/elec/any fan isnt operating anyways then there is another problem with the system, and id lean towards the blend doors...
 
Well, I finally cleaned the condenser today. It really wasn't very dirty, and by the time I was done it was late and cooling off, so we'll see if it made a difference.

I also checked the blend door, and found the tab on the very front door/valve of the whole heater core housing assembly broken. When I change from max ac to normal ac to bi-lev to vent, or what ever, the distribution between floor vents and dash vents doesn't change, and I'm getting a lot more air out of the floor vents than the dash ones. However, if I put it on defrost, it does start coming out of those vents, and it doesn't come out of them on any other settings. I don't remember it always being this way, and I think this may be the problem, unless someone can tell me it's always that way and I have crappy memory (very possible). Changing the temperature setting seems to work properly- if I set it to hot, it blows hot, and cools off as soon as I move it to cold. The exploded diagram in my manual is crap, so that didn't help me much, and I can't even figure out how it is supposed to operate based on it. From what I gather, there are actually 3 different doors/valves in the whole assembly? At least that's what I got from the service manual. I have no idea which controls which. I need to search online, just haven't gotten around to it. If anyone knows a good link that would save me a little time, I'd appreciate it.
 
Yeah, make sure the blend door is sealing up. That last thing you want is some of your air passing over the heater core.
 
Whatever I did, it cooled it off for the time being. It froze me out yesterday morning, and mostly kept up on a very warm afternoon- not quite where I think it should be, but considerably better. I still need to figure out how to fix it right though.

Then it wouldn't start this morning. Nice.:rolleyes: Never done that before though, so I think I can take once in the 5+ years I've been driving it every day.
 
You must log in or register to reply here.

Latest Posts

Top Bottom