Hydra,

The 2nd pic is exactly the same type of pump I used to own when I was still working in the HVAC business. it's a good price. I paid near $200 for mine way back then. You have to replace the oil in the pump every so often just like a car since the freon your pulling will eventually dirty the oil. You will see the oil reservoir leveler on front of the pump to show you how much oil and what the condition of the oil looks like.

 

I assume when you said you cancelled the heater A/C, you disconnected or bypassed the heater core to get freezing a/c temps?

If this is the case, this is a indication your blend door is not working correctly and allowing the mixture of the heater core and A/C coil. To fix the blend door, it requires a teardown of the dash to get to the heater core/ac coil assembly.

 

So change the oil..... Gottcha...... Type?

Also, When E-Vacing dose the pump hold the freon or do you need a bottle for it to go into. On the front of the pump you attach the yellow line to from the gauge but the is another that T's off from there. Basically 2 lines incoming because of this T. Which could be for E-vacing 2 pumps.

Still tho, where dose the freon go that you are E-vacing? In large machines I'm sure it has a canister but this smaller pump doesn't look like it has a empty 2lbs canister?

 

Normally, it should have a single port, you connect the center hose from the gauges to it and then when the vacuum pump starts up, you open up both low/high sides to began evac'ing the system.

This pump does not offer any way of recycling/recovering your freon. It is may strict to suck, suck suck. The pressure in your system must be ZERO'ED out before you use the pump, otherwise, you'll blow the oil out of the pump and have a mess!

I assume the dual valve connected to the pump may be used if you have different type of hose fittings? My pump only had the single universal fitting design for standard industry type freon gauges.

When it comes time to change the oil in the pump, you MUST use freon type oil, I cannot remember the numbers on the oil, but the manual on the pump will tell you.

 

'99 Durango, 5.2L, 210K, dual AC system.

Replaced leaking hoses and dryer/accumulator earlier this summer and still had a leak.

While I was putting off yanking the dash by charging the leaking AC system, a mouse ran into the fan and a thump, thump, thump sound ensued. Now I was pretty sure the heating coil was leaking, since I smelled antifreeze in the vent and we lost cooling water. I could also swear I smelled the freon additives, in the super cool, I was recharging with, in the vent. Seemed like with the mouse almost decapitating itself that now was as good a time as any to yank the dash and fix the problems I was pretty certain were going on. Besides, I like the smell of freon additives mixed with antifreeze in the morning. Or is that napalm. I always get them confused. But I draw the line at decomposing mice. I do have standards. That was kind of the straw that broke the camel's back. Now when I recharged the leaking system, it cooled like nobody's business. Still was cooling with the dead mouse in the duct, even. Seems since I yanked the dash out and replaced most of it that I can't get it too cool properly. Must be something I did, since the mouse is dead. Thanks to my wife for pointing out I can't blame it on the mouse. Still works for me.

Here are the vitals after charging the system:

Pulled 18-24 inches vacuum for 40 min before charging.
Added 1.876lbs R134a
Outside temp 89F
Condenser air 85F
Middle AC vent 71F
little High pressure line 174F
Suction line 84F
Hi side 250psi
Low side 50psi


When I took the expansion valve off and disconnected the AC lines, I wrapped the ends and the valve in glad wrap to keep clean and minimize moisture. Wife is always wondering where her glad wrap and wax paper. Wax paper is great to work on when making things out of fiberglass or epoxy. I am going to tilt the dash back to make sure the blending door is closing fully.

Seems to be too much of a difference in temp between the high and low side lines. Not sure what is causing it. Expansion valve maybe?

For what it is worth: my local Harbor Freight was out of the real vac pumps and I picked up one of the air driven ones for $12.00 on sale. The thing actually works pretty well. It pulled 24" Hg until the air compressor dropped to 65 psi and then it pulled 18" Hg. I have a 5 peak Hp compressor that is supposed to deliver 5.5cfm @90psi. Like that is close. There is no vacuum to cfm comparison, but there is a rating of 4cfm @ 90psi for operation. Recommended 75psi air delivery. It seems to give 20+ at 75 psi.

 

Wejones,

When you ran a vac on your system, did you test it for leaks before performing the vac procedure? Otherwise you may have pulled contaminates into your system during the vac and may cause bigger problems?

As far as differences in temperature for high and low, yes, there should be a BIG difference between the two. If there is no difference or slight difference, then your A/C is not tuned properly.

High pressure side should be hot enough where you cannot keep a grip on it for too long.

Low side, it should start sweating all the way towards the compressor. But it SHOULD NOT FREEZE all the way to the compressor.

 

Tested it with a vac gauge and it held 18" for 5 min. Turned out it was the blend door. The cable must have caught while putting back together and moved about 1/8" from the end. After fixing the cable got 53F @ 1500rpm with a 90F ambient and 100% humidity. I think the boss is going to happy enough to be friendly. She doesn't like the hot drive home from work. I took some pics, especially of the notorious firewall bolts. I can post if any interest.

 

Just a recommendation for future references, perform a positive pressure test for leaks instead of a holding a vacuum to test for leaks.

Using the vacuum procedure is dangerous because if there happen to be a small leak somewhere, it will slowly pull in external contaminants causing a bigger problem.