# Air Conditioning Help **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** civic, honda\ **Created:** [September 22, 2009, 11:25pm UTC](https://community.cartalk.com/t/air-conditioning-help/37013 "2009-09-22T23:25:15Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![tonlun](https://avatars.discourse-cdn.com/v4/letter/t/e68b1a/32.png) [@tonlun](https://community.cartalk.com/u/tonlun)\ **Post date:** [September 22, 2009, 11:25pm UTC](https://community.cartalk.com/t/air-conditioning-help/37013/1 "2009-09-22T23:25:15Z")
How do you tell if the expansion valve is stucked close or open? What kind of pressure reading would that give you? ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [September 23, 2009, 2:27am UTC](https://community.cartalk.com/t/air-conditioning-help/37013/2 "2009-09-23T02:27:02Z")
If the valve is stuck completely closed the high side should be abnormally high and the low side would possibly be showing very low pressure or even a vacuum; depending. What kind of pressures do you have? (and keep in mind that pressures vary based on a number of things.) ---
**Author:** ![tonlun](https://avatars.discourse-cdn.com/v4/letter/t/e68b1a/32.png) [@tonlun](https://community.cartalk.com/u/tonlun)\ **Post date:** [September 23, 2009, 3:37am UTC](https://community.cartalk.com/t/air-conditioning-help/37013/3 "2009-09-23T03:37:03Z")
Ok, let me tell you the whole story of my car. I just purchased a '94 Civic DX 4 door. It has 78K miles and the air conditioner was hardly used because the guy, who used to own it, lived in a beach community. The AC hardly blows cold air. In fact, I think it has a separate problem, the heater valve is not completely closing so that it blows warmer air than ambient temperature. Back to the AC, I recharged it with R134a kit that comes with a small gauge. I recharged it to normal (35psi) on the low side while at 1500 rpm and setting the blower to max. The AC blows cold air but as soon as I ramp up the rpm (2000 and higher), the low side goes down to about 22psi. At even higher rpm, the compressor would disengage. I do not know if this is the cutoff switch kicking in. The cutoff switch is mounted right on the condenser. I do not know what the high pressure reading is because I do not have 2-gauge setup. So I recharge it more hoping that the low side would stay higher than 25 psi. But as I did that, the engine seems to be bogging down close to stalling. Yesterday I bought a 2-gauge setup at Harbor Freight and I hooked it up. The low side read 25 and high side is 150. The higher I crank up the rpm, the lower the low side gets, and the high side would only go to about 200. I also found out that the schreader valve on the low side is leaking. I do not know if the R134a has escaped through the plastic cap so instead of 35 psi, I am getting 25 psi. When I drive it around, the ac blows cold air at idle but once I get going, it seems like the compressor disengages so no cold air. Few questions: does the cutoff switch cuts off at low pressure and high pressure? What makes the compressor disengage at high rpm? Where can I get the schreader valve? Do you think it is the compressor, having too much oil or the expansion valve getting clogged? How much oil is there in a small can of R134a? PS - I also replaced the drier and filled up about 2 can of R134a. Still have the same problem. Thanks.