1997 C2500 - little cooling from A/C

[kc2kth]

So my wife and I get in my '97 C2500 yesterday for what ended up being a 6 hour drive, and no A/C. Or so little cooling from it we were better off with the windows open.

I figured simple solution, get a can to recharge it. So I go out this morning, truck is running, A/C on max, connect mt can of R134 with the built in gauge to the low pressure port to measure pressure. But I don't have constant pressure here.

There is a device connected to the main belt that is directly below that low pressure port. The compressor I assume? Anyhow, this is cycling on and off every few seconds - maybe every 10 seconds. On, then off, then on again. As it cycles, my pressure gauge on the can of R134a is moving from "green" (need to recharge the system) to well into "yellow" (more than enough pressure, do not add).

What am I seeing here folks? Thanks in advance.

[kc2kth]

Just read an article that mentions measuring pressure at the low pressure port while the engine is off. I tried that and the gauge goes all the way to the red zone - well above any "safe" or "charged" areas on the gauge.

[taillight]

You sound like you are low on R134A But I have heard of all kinds of problems with these add on kits. Find someone with a set of guages or rent a set at an auto parts store. Or better yet call around and find a place that will do this for a reasonable price. If you have a problem that small can can blow up.

[MT-2500]

Originally Posted by kc2kth

Just read an article that mentions measuring pressure at the low pressure port while the engine is off. I tried that and the gauge goes all the way to the red zone - well above any "safe" or "charged" areas on the gauge.

Pitch that Wal mart recharge death kit.



With compressor running or jumpered to get it to run post back you low and high side readings at idle and at 2K.

With a ac recharging gauge set.
Like one of these.

http://www.ackits.com/merchant.mvc?S...erantGaugeSets
http://www.ackits.com/merchant.mvc?S...ory_Co de=DIY



Low side should be close to 30 lbs.
If it is dropping under 25 lbs the switch will cycle or shut off compressor.

Wal Mart DEATH KITS

You cannot properly and safely recharge an air condition system with them.

The one side stop and go gauge does not tell you what your system is doing or is over charged or undercharged.
A overcharged or malfunction air condition system can reach over 500 lbs of pressure.
Enough to blow up that can or system and freeze you at first and the burn you or blind you and if any propane /butane in there blow and light you up.

The stop leak crap and who knows what kind of oil in the kits there will stop your system for sure.
Just like pouring super glue in it.
And some kits even contain freon with a butane mixer.
Good for a big blast.

If you are going to do it do it right and safe.
Here is what you need to start with.
http://www.ackits.com/merchant.mvc?S...erantGaugeSets

In the older days you could just throw in a can and go.
But over the years just adding freon is getting harder to do.
Newer systems have to have the correct amount of freon down to the ounces.
Most will need pumped down and vacuumed down and the right and amount of oil and a set amount freon charge installed to get the air to cool right and the system to last.
If an air condition is low there is usually a leak that needs fixed and also a lose of lubricating oil from system.
Also air and moisture enters a low system
If you are going to try to do it get the proper type air condition gauge set with the low and high side gauges.
Hook up the gauges and get a reading with compressor running at idle and at 2000 rpm on the high and low side.
Post back pressure reading and we can help you.
MT