anyone familiar with this setup?my a/c system holds a charge for a few days,then while sitting at a stoplight or parking lot,the engine idles rough and then a puff of 134a vapor escapes.i have changed both lines and all the o-rings,but not the compressor and the evaporator core.the system has UV dye but i can't find the leak anywhere.(compressor,lines,condenser)i suspect the evap core but i don't smell any freon when it happens.a/c parts are not cheap-the dryer line from the comp to the firewall was $225 at shop cost.i can do the work,but i'm not sure where to go next.does anyone have any suggestions?...any links?...anything?thanks y'all.
a/c question for 01 grand cherokee w/4.7L
- Thread starter robzkool2
- Start date
SteelHeadz
Super Moderator
The issue your describing sounds like a restriction in the system, not a leak issue.. First question; is the electric fan kicking on when the a/c is running?. Second question; does the a/c cools like normal before the refrigerant blows out of the A/C compressor pressure releif valve?..Don't forget , out of all the components you mentioned there is also a condenser thats required to be cooled down by the electric fan that i mentioned earlier. Too much heat on the condenser will build up exessive head pressure and will have to escape thru the pressure releif valve. A plugged up condenser or evaporator can also cause this issue.. Both the suction and discharge lines should equalize in pressure after you charge the system. You can monitor this pressure with the use of an A/C manifold gauges.
to steelheadz-thanks for the quick reply.
as to your first question,i have a hydraulic powered fan assembly,so it turns with or without the a/c on.although the fan blade seems to be turning slower than it should,just by eyeballin' it.but the coolant temp gauge doesn't get past the center mark.i did have the idea to install a secondary electric fan in front of the condenser.
and to your second question,yes it blows cool up until it pops the pressure valve.i did see that my truck has been hit in the front.the condenser has been replaced and the air deflectors on the sides of the radiator are missing.just wish i was the one that did the work.(collision repair tech 15yrs)
i got the bad feelin' that i'm gonna end up breakin' down the system and checkin' each part individually.bummer.
as to your first question,i have a hydraulic powered fan assembly,so it turns with or without the a/c on.although the fan blade seems to be turning slower than it should,just by eyeballin' it.but the coolant temp gauge doesn't get past the center mark.i did have the idea to install a secondary electric fan in front of the condenser.
and to your second question,yes it blows cool up until it pops the pressure valve.i did see that my truck has been hit in the front.the condenser has been replaced and the air deflectors on the sides of the radiator are missing.just wish i was the one that did the work.(collision repair tech 15yrs)
i got the bad feelin' that i'm gonna end up breakin' down the system and checkin' each part individually.bummer.
SteelHeadz
Super Moderator
Are you sure there's no electric fan behind the radiator?. I'm quite positive that the GC's ,specially the 4.7's were built with a Hydraulic and electric fans..
Thre are 2 fuses that protects the circuit on this fan, one is on the power distribution center under the hood. Refer to the PDC cover for its location, 40 amp fuse. The other fuse is located in the junction block, 15 amp fuse..
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yep.positive.all i have in front of the engine is the hydraulic fan,radiator,condenser,oil cooler,grille.no electric fan.not even mounting holes for a missing fan.i checked the PDC for the fuse for the electric fan-just a blank spot with just one terminal blade.i'll have to pull the front bumper cover to see if i have a fan relay-it would be under the RH headlamp-but i doubt it.
i have a haynes manual that says the hydraulic fan is controlled by the PCM through a hydraulic control valve to control fan speed.and to troubleshoot,i would need a DRB III scan tool.$$$.alldata made note of a late '01 chrysler update (mine was built mar 01)for the cooling fan at the dealer.
i have a haynes manual that says the hydraulic fan is controlled by the PCM through a hydraulic control valve to control fan speed.and to troubleshoot,i would need a DRB III scan tool.$$$.alldata made note of a late '01 chrysler update (mine was built mar 01)for the cooling fan at the dealer.
SteelHeadz
Super Moderator
That's new to me. It would not be nessesary to pull the bumper since the PDC is blank anyway. As for diagnosing the hydraulic fan, yes you will need a DRBIII to be able to monitor and actuate the solenoid on the hydraulic module.
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