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Nippondenso 10PA17C Leak Check

scusack71 on Fri June 24, 2011 8:14 AM User is offline

Year: 1998
Make: Dodge
Model: Intrepid
Engine Size: 3.2
Refrigerant Type: R134a
Ambient Temp: 80
Pressure Low: -
Pressure High: -
Country of Origin: United States

I have a Nippondenso 10PA17C I had rebuilt last year that has been sitting on the shelf sealed up until I could put it in. I'm about at that point but I wanted to do a leak check on the pump and evaporator first. I already did a flush with my HECAT, purged, popped, purged and capped. I have purchased new hoses and cut the old ones up to use the ends for adaptors for my vacuum pump (I threaded AN fittings in the cut ends of the aluminum).


I did attempt to do a leak check on my evaporator utilizing the adaptors I made connected to my old expansion valve (which I ended up reaming out the valve side for flushing purposes). The vacuum drops to about 1200 microns and hold for about 10-mins and then when I close the valve and shut pump off it slowly climbs out of vacuum. I am using the original seals for the adaptors going into my expansion valve and the original (hour glass) gasket for the expansion valve and thought that may be my issue. I'm praying its not my evaporator, but I know that probably the only real way to find out is to plug the whole system together and see... but I guess I'm trying to eliminate through process of elimination first and avoid the extra work since the whole system is completely removed now due to a 2.7/3.2L swap I'm doing. Should I put new o-rings and gasket instead (and buy another o-ring kit for final assembly) or just wait to put whole system together to verify?

PS: the expansion valve has a thin metal, rubber coated hour-glass shaped gasket... can I apply a thin film of NYLOG on both sides of it when i'm ready to install the whole system?


I took the capped (old lines adaptors) and installed them to the low and high side ports. The low side I connected a micron gauge via AN T-fitting. The compressor has the High and Low side service ports on the compressor so I connected my service gauges via quick-connects and connected it to my vacuum. Vac drew down to about 1200 microns and started to slowly increase. So I rotated the compressor slowly to maybe get the small about of lube on the seal to hopefully seal up. The vacuum dropped back down to 29.86 "Hg and stayed steady for about 10-mins. I closed the low and high service valves on my gauge set and could see it slowly climbing up. Could this be due to:

A. No lubrication oil in the system (only light oil lube used for assembly) not sealing shaft seal well enough?
B. Using original o-rings on the low/high side ports could be leaking?
C. Leak Checking the pump alone not feasible since volume is so small?
D. All the above?

Not sure what I can do to ensure I'm doing this correctly. Any help greatly appreciated. Sorry if my questions seem crazy or not explained well.

mk378 on Fri June 24, 2011 9:30 AM User is offline

That evaporator may be from the era of leaky Dodge evaporators, in that case you absolutely should replace it and not mess with the original. Though, is the Intrepid really a Mitsubishi something? If you really plan to reuse the evaporator, test it under pressure, air or nitrogen, use no more than 150 psi. Put soapy water on it or submerge the whole thing in water. You could do the same thing with the compressor but be careful not to get it too wet. Seal leaks are easier to detect if you take the clutch plate off. There are cases that will leak under pressure but hold vacuum, and vice versa.

HECAT on Fri June 24, 2011 10:56 AM User is offline

Are you sure your old expansion valve (drilled open flush fixture) is not allowing internal leakage (port to port bypass)?


HECAT: You support the Forum when you consider for your a/c parts.


scusack71 on Thu July 14, 2011 5:32 PM User is offline

Well, sorry it's taken a while to post back.

I ended up replacing the evaporator just to take the doubt out of the equation... good experience since I had to remove the dash and HVAC box twice since I forgot a piece of insulating foam I forgot to install around one of tubes on the evaporator (was losing sleep... just wanted to make sure it was right).

Everything else is brand new with exception to my compressor that I rebuilt. I took the recommendation from mk378 and removed the clutch assembly, felt ring, retainer and then applied 120psi (my compressor max) and pressurized the compressor and submersed it in water in our utility wash sink and looked for bubbles.... didn't see a single bubble. I didn't leave it in for but just about 30-seconds to make sure. Made sure the valve caps were removed also. I immediately blew everything dry and reassembled.

Also, just to clear my conscience, I also submersed the evaporator with 120 PSI and sure enough.... many many bubbles... I'm the glad the replacement wasn't in vain... and thank you very much mk378 for your suggestions in clearing my sanity.

I just wanted to make sure that 120 PSI is good. I was told not to exceed 150 PSI but wasn't sure if I needed to make it that high or not? Cuz I'm super ready to get this thing together!!!

PS. I removed the clutch retaining bolt with an air ratchet but now didn't know what to torque this 6mm bolt to. Also, how to keep the clutch from spinning so I can apply a torque... hands start to slip but very sure it's not tight enough.

Edited: Thu July 14, 2011 at 5:55 PM by scusack71

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