R-12 to r-134a conversion problem

[Pelican]

Gray XJ, does your A/C always blow through the defroster vents, accelerating and idling?

The vacuum reservoir bottle itself can fail as can the check valve.

 

[Gray XJ]

Yup always blows through the defroster and all the hoses to the bottle and the acutators seem good, Ill do the smoke trick tomorrow though.So you think my bottle just might be bad?

 

[Pelican]

Ecomike and others can tell you more about the vents themselves. When I had the failed reservoir problem, the A/C would blow through the proper dash vents at idle when the vacuum was high. Looks like you may well have a different problem, but unless someone comes up with a more definitive answer, it couldn't hurt to spend a few minutes checking the system a bit further.

 

[Ecomike]

Hey EcoMike, how did u find that vent door issue and how did u fix it?
My AC only blows from the defroster vents and i have checked all the small hose that goes near the battery to the bottle in the bumper ,and thats all good, so i was thinking it was a stuck valve or flap somewhere.

On the passenger side, under the dash near the jeep door, is a duct damper door that allows outside air in (or not) on the way to the evap coils / heater coil. It is operated by a spring to open, vacuum valve and a lever to close operation. The A/C heat slider controls operate multiport vacuum valve and mechanical levers that operate three damper doors in the dash area. A broken mechanical rod (unlikely) or loose vacuum line, or bad diaphragm on the vacuum valve (my valve was bad, and I had vacuum leaks in mulitple places) can cause outside air to get in or air to pass over the heater coil if the blend door does not close. There is an inside/outside air blend door, and evap coil / heater coil blend door. For Max AC you want all Evap coil air flow, and no outside air, and no heater coil air. IN Deforst the blend doors use only inside air, and the air crosses the Evap coil then the heater coil to remove humidity with out a net lowering of the interior air temperature.

 

[Ecomike]

Some of vacuum leaks were under the hood, some were small and hard to find, and other leaks were inside, under / behind the dash. Radio work in the dash can knock the hoses loose on the dash controls.

 

[Johnnie Walker]

In some systems/vehicles R-134a can work as effective as R-12 did. But, I have never gotten any R-134a system to be as cool as the coolest R-12 system I have done. And R-134a is also a cost effective swap if your R-12 system is not functioning.
A/C is overrated anyways.

 

[stephenspann27]

In some systems/vehicles R-134a can work as effective as R-12 did. But, I have never gotten any R-134a system to be as cool as the coolest R-12 system I have done. And R-134a is also a cost effective swap if your R-12 system is not functioning.
A/C is overrated anyways.

Yea if you live in California like you.. try sitting in traffic in Texas summer heat and humidity.

 

[RichP]

Who is going to bust you on that?

Same people who check labels on mattress and pillows LOL...

 

[winterbeater]

or tha peeple on forims hoo r awlweighs carecting gramer an pnctaton

 

[Pelican]

Winterbeater, if I had to guess, I would assume you just came in from bleeding your brakes.....

 

[stephenspann27]

My air is blowing through the proper vents at idle and low RPM, and through the defroster vent at < 1/2 throttle. I should check the vacuum line to the bottle right?

 

[Pelican]

The lines and the bottle itself if the lines are okay.

 

[Ecomike]

My air is blowing through the proper vents at idle and low RPM, and through the defroster vent at < 1/2 throttle. I should check the vacuum line to the bottle right?

Engine vacuum drops when accelerating (1/2 throttle?), and that is when a small leak shows up in the AC damper control circuit (like your current complaint). I had a brand new piece of rubber vacuum hose that had a defective inside core right near the passenger side fire wall that fed the vacuum to the entire AC interior controls, that did the same thing. I had turn off the engine (I had help at the ignition switch) while I quickly listened under the hood for a very tiny leak sound. Never would have found it visually! The audible leak sound only lasted about 8-10 seconds. Engine is too load to hear small leaks.

 

[Aquit45]

If you take two cherokee's lets say 1990's. One has a R12 system working to factory specs.
The other has a system R134 that you took all the old R12 and filled it up with new r134 and you didnt change any other parts. Dont care what anybody says if its 115 outside, there know way in hell that the r134 sytem is going to get as cold as the r12.

On the other note it only cost me $200 to have my 90' filled back up with R12.
It turned out that the comp was leaking from the front seal. So $700 later. Its blow ice cold.

 

[Pelican]

Perhaps. For ~$650 I'll take bit less cool and put a can of 134 in every couple of years.

 

[stephenspann27]

Mine is cooling great with 134A so far.. but I'm not a good judge because I never felt it with R12.. but it cools REALLY well.. I'm very impressed.. as for my vacuum leak.. I think I got it fixed. I had broken the vacuum line from the canister to the firewall a while back, and put the broken sections back together using rubber hose. I put silicon on each end of the rubber hose where it slides over the vacuum line.. I think that fixed it.