New to the Forum. Finally got my dream car 16 years after it was introduced, 2003 H2. My kids named it Bumblebee... but after spending more time under the hood, discovering various hidden unprofessional battlefield repairs, it has been renamed affectionately... FRANKENSTEIN !!!!! Dont get me wrong, I love to tinker and it has proven to be the ultimate tinkertoy and it is absolutely effortless offroad but I'm in a bind that seems bottomless. the type of issue only like-thinkers can relate to! 3 weeks ago the AC quit and the compressor would come on for a few seconds, kick back off for 10 sec then back on for 5 sec, etc. freon was good and pressure in normal op range but the compressor was grinding while on so I replaced the whole system. I replaced the condenser, compressor, evaporator, lo press sensor, orifice tube and all associated o ring seals. I vacd the system down, it held for 90 min. As I recharged the system and pressure came up, the compressor started the same on off cycling during which the high press side showed 100 PSI but the low press side would rise to about 90PSI, comp cycled on dropping it to about 30, it cycled off and climbed back to 90 and so on. Still blows hot air and cycles on n off no matter where the temp or mode is set. Can anyone offer me advice for my monster or do I gather the villagers to help me put it out of its misery?! Thanks for the help and I look forward to sweat free rides!

 

Make sure you are going by pounds of refrigerant by weight, not psi. Did you put the office tube in long end first or vice versa? Make sure your vents are all working and fan/blower is on high, It almost sounds like you have a bad actuator too. Pressure will be off if there is not enough air flow.

Tim

 

did you put in a new orofice tube?

 

Is this a quiz? Failing compressor sent shrapnel into the system. Replace compressor/accumulator/orifice/flush the system, evac/refill with the proper amount of pag oil & refrigerant. DONE!

 

Ya, replaced the orifice tube along with the rest of the components. followed the service manual to the tee. the biggest issue is the pressure swing on the low side from 80 PSI when the compressor starts to about 30 PSI at compressor cut off, about 5 sec. then that process repeats itself. Its almost as if there is an obstruction in the system but I cleaned, flushed and or replaced everything in the AC system except the evaporator core inside the dash. Could that be the culprit?

 

Thanx for the reply, no quiz. I did exactly everything you listed replaced the compressor, condenser, evaporator, orifice tube and pressure switches,. flushed the system, vacd it down and it held for 90min. and refilled. The stumper is the pressure swings on the low press side climbing to 80 PSI, comp kicks on and press drops to 30, comp kicks off, presssure rises to 80 again, comp kicks on and the process repeats. the only thing I didnt replace is the evaporator core inside under the dash. but it flushed out fine. Could it be obstructed or possibly the orifice tube defective? I jumped the connectors on the pressure switches to see if the compressor stayed on and it did but the extreme pressure swings were a little unnerving and it had only taken 18 oz of refrigerant. like I said, its a stumper, thats why I came to you guys. I appreciate the help, back at it tomorrow.!

 

i think full is about 25 and a half ounces. give or take an ounce depending on year

 

That's correct.

 

I may be missing something but what you are explaining is exactly what will happen until you add enough refrigerant

Neal

 

are you using a set of service gauges to verify the pressures?

Neal