Automotive Air Conditioning Information Forum

Issues with 1998 Dodge Ram 2500 AC

I had a hole get rubbed in aluminum lower pressure line. I tried to run AC for weeks (probably compressor never came on) until I tried putting in coolant and could hear it blowing out the hole.

I replaced the line, used off ebay, so not sure about it. New accumulator. Added oil to the high pressure line and some in the condenser (at the radiator/front). System holds the vacuum for days.

Was not able to add coolant. Did the vacuum for an hour, then with manifold tried coolant, but compressor never came on. 12 volts at low switch and none at compressor clutch.
I jumped the relay to make clutch engage but still nothing happens - clutch spins but no coolant is sucked in and the psi stays exactly the same. The gauges say about 80 psi on both high and low (I think the 80 is what the can pressurized the lines up to, since it was a vacuum before, is only way I can think it got pressurized). There was coolant in the window, but on second attempt after unhooking and rehooking with differnt manifold it all there was no coolant in window). While it is possible that the rental tool is bad, I doubt it as I was able to pull a vacuum on the system (noticed different pressure initially with valve closed then open), but who knows… Not a lot of moving parts on the manifold. Also, fuse is good.

Compressor should come on if system is at 80psi, but unless the pressure did not make it back to the valve/switch somehow. Everything worked before the hole, so I have to assume something electrical did not go bad just coincidentally in the few weeks. But seems like something electrical since I know the wiring between relay and clutch is working, would have to be the panel switch, or is there CPU involvement?

I suspect a 100% clog somewhere. Should I assume that? Means I need to do a flush.
flush questions:
Is the new dryer fine? no circulation seems to have happened so should not be any debris moved around.
I have read that some vehicles, newer, if a clog happens the condenser (or is it the evaporator?) cannot be un-clogged and needs to be replaced. These are $80-100. The evap, in the dash, is way too hard to replace so is very last on the list of things I want to do. Do I need to replace the condenser on a 1998 Dodge ram?
Compressor seems fine. If debris, can it be cleaned?

Common fault is service connectors that are not depressing the Schrader valves on the vehicle fittings.

You evacuated the manifold & hoses. Then you charged the manifold & the hoses. A little bit of refrigerant will slip past a closed Schrader valve, so some pressure may have entered the system.

Do NOT jumper compressors to run. All this does is run the compressor with no oil returning to it. They do not "suck in" refrigerant. If the system was properly evacuated & the service valve open, it would have sucked in refrigerant even with the engine shut off.

Rental gauges may have been the issue.

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That's a good point. The gauge did get to 30 vacuum pretty quick so maybe it was just the hose getting vacuumed. How long does it normally take for the psi to drop? More than 10 seconds?

I have already ordered new parts, but will try it again with different tools first.

marininn wrote:The gauge did get to 30 vacuum pretty quick so maybe it was just the hose getting vacuumed. How long does it normally take for the psi to drop? More than 10 seconds?

Time to get to 30 psi vacuum? Yes, longer than 10 seconds, may take several minutes !

Hmm, I tried so many times… Maybe the first time it jumped to 25 quick and took a few mins to hit 30, but I cant remember. Each successive time it would make sense to hit 30 quick if the system was actually vacuumed correctly and already at -30. The pump works, but as you say, not sure about the gauge and ability to depress the valve, but given there are two valves (high and low side) wouldn't it just need one of those to pull a successful vacuum over a 2 hour period?

Also, that when I jumped the compressor and nothing happened to gauges is good indication that gauge is not open to the system? And that the bottle of coolant should pressurize the system to whatever the bottle psi is, which it is not doing because when I disconnect n reconnect I should see that psi still there. So maybe is just the manifold hose getting pressure???

My thinking, since new parts are on the way, do I try once more to charge system? Should I try with that $20 charge that comes on the bottles? I would have to jump the compressor again. I dumpped oil in, so there should be some to start with at least.

Got nothing to lose, so
I put a can 134a in with the little recharge that comes on cans.
The compressor came on by itself because the system actually had pressure. It pulled the whole can in. I am not sure if that half can from before ever went into the system or if it just was in the hose of the bad manifold and got purged to lose half a can…
It runs cool enough with just this can.
The compressor cycles every 4-6 seconds though. pressure in little gauge is 22 to 58 as it cycles.
Maybe more coolant will fix the rapid cycling?
I want input before wasting any more coolant.

I do have new parts coming tomorrow, but am fine shelving them if I can keep this working as long as possible..

Maybe this confirms Autozone rental tools were broken? Also confirms that system is working as good as it was when it lost pressure. Compressor cannot come on without coolant(pressure) in the system/

Also, a friend said he does it many times with no issues. He relies on the drier to absorb the moisture in the system. I do not like this theory, but worst case I have new parts on the shelf…. It is a new drier, so at maximum capacity at least..

*** BEWARE OF AUTOZONE.COM RENTAL TOOLS. JUNK JUNK JUNK AND BROKEN Staff puts known broken tools back into circulation even if told it is broken

I agree that the rental manifold gauge set connectors probably aren't depressing the vehicle's shrader valves. Assuming for a moment that the connectors themselves aren't defective, they can fake you out in that rotating the knobs CLOCKWISE (not counter-clockwise) actually depresses the shraders for evacuation and charging. Just ensure that you're turning them in the right direction and that they're properly secured to the fittings.

Also, many of the charging kits contain refrigerant and sealer. You definitely don't want sealer in your A/C system because that can really clog things up, creating additional expensive problems that weren't there before. Our local AutoZone carries their own brand of pure R-134a, as well as the Chemours (DuPont) brand. If you charge with either of those products, you'll be assured of not introducing any sealer into the system.

LOL

I have seen $100 SnapOn connectors fail to depress out of spec Dodge service port valves.

The last 5 people that used that loaner tool probably had no trouble at all.

What you have in that system right now is a mess. It was never evacuated, and now has a mix of non-condensable gasses and some refrigerant. It needs to be recovered & evacuated properly, then charged by weight.

I plan to get hopefully a working set of tools and do it properly. It takes 46oz so I will just put close to that in.
Possible the schrader valve was out of spec, but I would not think both of them, and dont know how to check. With schrader valves the valve core can come loose, but that would mean it would contact the tool sooner and for sure open. What is spec and how would the valve core be further away from the tool so as not to get depressed?

I did operate the tool correctly

Are you sure the system takes 46 ounces of refrigerant? My reference material for your vehicle says 32 ounces of R-134a and 8 ounces of PAG-100.