speyguy

I did a A/C search and read thru all 14 pages. My A/C is not blowing cold so I bought a low side gauge/recharge hose and checked it. It just continually cycles between 25psi and 65psi in a 7 second interval. Just like clock work, the gauge drops to 25psi and builds back up to 65psi over 7 seconds, the compressor clicks and starts the cycle all over again.

Suggestions??

Do I need to buy a seperate gauge to check the high side? It appears to be a larger fitting.

Also, it did not seem to take a charge from a fresh can of the R134. I have read to keep the can upright so as to get gas only and not liquid, and also to heat the can and turn it upside down. Which is correct?

oldblues

hi
i have a a/c prob also!

mine will cool to 60 DEG when i first turn it on then it gradualy will warm up to 80 deg and stay there ????
i noticed the condenser get prety warm/ hot all over ????
i have a new belt and a new made iin china fan clutch ?
in my opinion it does not seam to move much air and reving the engine does not seem to increase the fan speed much ????
first diesel so i dont know nuttin bout it !

we need help here boys .
i have some gages so i guess i need to hook them up and see whats up ?
what shoult hhe readings be at what temp ?
how cold should the air be at the vent ?
thank you !!

clutch1

not sure how the temp is there but you really need to see both sides of the system to check properly high and low your compresor could be cycling for many reasons. you only want gas to go into the compressor gas goes to the top.you can warm the can but not to warm.

clutch1

all depending on the condition of your system. say its 90 ambient temp your high side might be somwhere around 240 low side 30. your condensor is on the high side of the system so it'll be warm just touch the lines on the compressor low side cold, high side hot.

CarBizIndio

The correct way to diagnose the problem is with a high and low side gauge. It sounds like your compressor is in need of more R143 with it cycling so often but its not a very good sign seeing it not take more 134 you mite want to test your A/C low pressure switch.

speyguy

Can you tell me where this is located and how to do it?

CRSmith

The compressor draws from the side you are measuring. So when it kicks down to 25psi, the compressor is drawing down the pressure. Then the compressor cycles off and the pressure builds to 65psi.

In my opinion, you have too much refrigerant if you are seeing 65psi on the low pressure side. If memory serves me, it should be like 35psi at the highest, but someone with a manual handy can confirm this. The cycling of the compressor is within spec (10 times per minute is what the shop manual says).

I would try releasing some refrigerant in 5 second bursts to see if the air starts to blow colder. This might be illegal, and some say r134 is unhealthy, so you'll have to figure those out on your own.

vzdude

Need more freon. You can tell you have enough freon when the pressure ( compressor not engaged) is the same as ambient temperature. So if its 90 degrees out, pressure should be 90 in the system when its not engaged. If you are only seeing 65 it sounds low. Engaged you should see around 30 on the low side, and depending on engine tem and such around 300 on the high side. Need to know both pressures to properly diagnose the system.

junkman1946

Speaking of A.C. I too have a problem. Hot air. Put the gauges to it 35lbs. low side 75 to 80lbs. high side. Clutch cycles infrequently. Tried a can of R134 would not take it. High pressure line from Dryer is ice cold about half way back to the high pressure fittings. System worked great last yr. Any ideas? Thanks Frank

pull-do

Sounds like a restriction in the line where the icing is occuring, pressure differential hence the icing.----------

Or after re-reading, is it actually icing up?

jrs_dodge_diesel

Not quite. When the system is idle (compressor not running) the refridgerant pressure is even on BOTH hi and low side (in equilibrium). Normally this is around 75 PSI. Could be higher or lower based on ambient temps.