if you have the stuff its not that hard, fix leak vac it down turn some ***** and valves and fill it until the psi is right, its nice to have a set a gauges cause than you can get adapters to check freon in all sorts of things, even your home ac assuming it is also r134a

 

I'll try to get Norfolknova to check this thread, he seems to know A/C systems well.

 

automotive AC certification is only around $50. the systems are not that complicated either.
a good vacuum pump will run you between $100 and $200, and a manifold set is under $100
same with a sniffer, between $100 and $200
my vacuum pump, OTC sniffer, and MAC manifold set cost a total of $175. i bought the manifold set and pump 4 months old slightly used from a shop going out of business, and the sniffer new on sale from amazon.com for $75.
i buy freon bulk online from lenz distrubiting in Fla for $55 per case when i buy 5 cases.

i maintain 14 vehicles, so i use 2-3 cases per year on average.

 

With ou tknow what the high pressure side is doing every one is simply speculating. Even a cheap set of auto a/c gages would be better than not knowing what the high side is doing.

One of the first things I tell the young sailors when I am teaching them is start with the basics.

Make sure your condenser is clean, spray it with some degreaser and hose it off.

Make sure your evap is clean, these trucks did not come with cabin air filters, When they are run in the fresh air mode dirt and leaves can get caught up in the evap.

If you are only running 25 psi then you are more than likely low, R134a should run 35 psi on the suction side. 35 psi will give you a an evap temp of 40 degrees and with a good clean evap an air temp of 55 degrees. If you run below 25 psi you will start to freeze moisture on your evap, thats why the lp switch is set there.

Clean your condenser and get a set of gages then take running readings. High pressure, low pressure, outside air temp, air coming out of the vent temp. With those we can tell better what is going on

matt

 

Another check you can do with out a high pressure gage is this.

First thing in the morning hook up your low side pressure gage. Also get accurate reading of out side air temp. Tell me what the gage reading is, it needs to be pretty accurate, You can use these two readings to determine if you have air in the system.

Here is a PTR chart for R134a. Once you get your ambient temp look at the PTR chart for that temperature, then see what the corresponding Pressure is. If the gage pressure is higher than the PTR temp then you have air in the system and will need to have it recovered , find the leak, fix the leak, evacuate, and charge.

Here is a link to a PTR chart
Pressure - Temperature Chart for HFC-134a

Matt

 

Thanks for the input Matt, and don't worry, I won't be chasing you around every time something A/C related comes up.

 

Feel free to ask any A/C questions when ever you need to, I just have a lot going on with work and my side business, so i don't always have a chance to get on the forums and read all of the posts, but if you shoot me a PM I will see it on the email and know I need to come look

matt

 

Yeah, I dont do enough a/c work to justify spending 400 on the tools.


norfolknova thanks for the help. I'll see if I can get some numbers before I go to work

 

Just remember, a couple times getting work done at a shop on the A/C system and you might as well have bought the tools yourself. I use this justification on all sorts of specialty tools because in the long run its cheaper, and my tool collection grows as a bonus.

Not to mention the satisfaction of being self sufficient.

 

That's my line of thought ^ . If I hadn't bought the pitman arm extractor the first time I would have regretted it the other 3 times the seal has crapped out.

 

agreed here too.
the tools paid for themselves and saved me money the first time out.

 

Pretty sure I got it fixed.

Took it to a shop up the road to check pressures. He said everything looked good. 50low 250? high.

Anyway. checked the temp at the inlet of the condesensor and it was 49*

He was thinking blend door issue. Well i did have all that apart when I redid the truck last fall. Anyway. with a slight adjustment of the cable at the control **** and I have 56* at an idle. I need to go for a ride

 

sounds like you got a handle on it.
besides checking the blend door for full closing, check the inside/outside air door too. if it hangs open a bit you will get some outside air in when on max AC and it will not cool as well.

 

While you you have the blend door fixed, not all is right with your system still, 50 low/250 high is wayyyyyy wayyyyyy too high. You are running pressures like you are using R404A and not R134a. I would say you do have some air in the system, or a serious overcharge of refrigerant.
You air in the truck will actually be colder if you can get the pressures down where they need to be at 35 low/ 150-180 high. Your high side will vary depending on outside air temp because it is an air cooled condenser.

Let me know if you have any other questions

matt

 

agreed . i missed the high pressure readings. those reading would only be appropriate if it was around 110 degrees outside temperature.