AC help with my Jeep

[Ozwynn]

since nobody has answered in the Jeep forum, I will ask here.

Anybody in here that’s a mopar mechanic that would have the specs for the AC system on a 2008 Grand Cherokee 4.7L?

like what to vacuum it down to over how many minutes and how long does it need to hold vacuum? How much Freon charges to what pressure?
Do I need to add any oil other than what came with the new

 

[black_demon69]

first question does the system function? second Question do you see any visible leaks @ connection points or hoses and possibly compressor and service ports? as far as vacuum pull down as far as you can longer is better it helps remove moisture and air.. hold time I usually give at least an hour. r134a capacity 1.5 lbs 4.4 oz ND-8 PAG oil capacity.
this information is from ALL DATA FYI.. I do recommend replacing the service port valves as these are a common leak point. if system did not loose any oil I usually don't add any unless I have system open and have replaced components other then service port valves.

 

[black_demon69]

DO NOT USE ANY A/C SEALER !!!!!!!!!

 

[Ozwynn]

Thank you for the reply. I took a fence post through the condenser so I’m replacing that this weekend along with the receiver/drier, expansion block, and hoses. Basically everything but the compressor, sensors, and evaporator.

The compressor did function right up until I impaled the condenser….. I unplugged it right away so it couldn’t continue to try an cycle with the defroster. Should still function fine.

I hadn't planned on using any sealer but I am replacing the o-rings and going to use Freon with tracking dye ….

 

[black_demon69]

you are welcome

 

[55trucker]

Anybody in here that’s a mopar mechanic that would have the specs for the AC system on a 2008 Grand Cherokee 4.7L?

like what to vacuum it down to over how many minutes and how long does it need to hold vacuum? How much Freon charges to what pressure?
Do I need to add any oil other than what came with the new

Generally all suction side manifold gauges bottom out at 30 inches vacuum, that's what you vacuum to. Shut down the pump & leave system for a minimum of an hour.
As for *refrigerant*, there should be a sticker somewhere in the engine bay letting you know what the weight of the 134a charge is.

There is no real *put in this much weight & you get this much pressure*, charge to the spec provided by the advertised weight.
I see you've suffered a catastrophic failure, you'll need to find out what the system was designed for where max oil capacity is.
if you pull off the compressor and drain all the oil out that will tell you what just the compressor holds, subtract that from the total & you get what the rest is entitled to.

 

[Dirtman]

Did the radiator itself take any damage?

 

[Ozwynn]

Did the radiator itself take any damage?

Nope… the condenser took all the damage

 

[Dirtman]

Good. Seen alot of those 4.7's die almost instantly after a loss of coolant. They are the jeep equivalent of a 2.9 . Good motors but NEVER OVERHEAT ONE!!!

 

[Ozwynn]

Good. Seen alot of those 4.7's die almost instantly after a loss of coolant. They are the jeep equivalent of a 2.9 . Good motors but NEVER OVERHEAT ONE!!!

I’ve been leaking from the water pump weep hole for 6 months …. I have to refill the recovery tank once a week but haven’t over heated yet.
I have the water pump… somebody flushed this themselves and used green coolant and Jeep says it needs orange or blue so I’m waiting until I can get an opening at a shop for a flush. I don’t think the HOA here will take kindly to me flushing the coolant in my driveway since they bitch about be washing the mud off in my driveway….

 

[rubydist]

to add to what 55trucker said, you vacuum it down as close to 30" of vacuum that your pump will get you. When you leave it for an hour, the vacuum gauge should not change. If the amount of vacuum is reduced while it is sitting, that means you still have a leak somewhere and you need to find and fix that before you can fill it with refrigerant or else it will just leak out on you. And too much oil in the system is just as bad as too little, so don't just guess at how much oil to add.

 

[Ozwynn]

to add to what 55trucker said, you vacuum it down as close to 30" of vacuum that your pump will get you. When you leave it for an hour, the vacuum gauge should not change. If the amount of vacuum is reduced while it is sitting, that means you still have a leak somewhere and you need to find and fix that before you can fill it with refrigerant or else it will just leak out on you. And too much oil in the system is just as bad as too little, so don't just guess at how much oil to add.

I drained the compressor and added 1.5oz and put 3oz in the drier per instructions on the drier.

it’s been holding vacuum for an hour. Now I need to figure out how much transmission fluid goes back in the cooler (because on this the condenser and the transmission cooler are the same unit) because it has a really complicated procedure for checking the trans fluid.

 

[55trucker]

Is that trans by any chance a sealed trans?

 

[Ozwynn]

Is that trans by any chance a sealed trans?

I doubt it… I can remove the pan and change the filter…. Has a dip stick.

AC took 23oz and is regulating nicely at 50psi on the low side… it held vacuum for an hour and is blowing cold…. Thanks for your help

 

[55trucker]

Glad to be of service,

so the trans isn't one of those NAG1 creations by Daimler........