Automotive Air Conditioning Information Forum

drive ratio is diameter of belt on crank pulley divided by diameter of belt on compressor pulley.

looks like a nice compressor, Denso competitor to Sanden for heavy truck applications, nice unit.

Does the TXV have an adjustment screw you can see, or sometimes it's inside the low pressure port and can't access it while running, can you take a picture?

What is the temperature of the suction pipe (metal) near the compressor when it's running 1500RPM, high blower? thermometer insulated in great, put your fingers on it is ok too.

Where is the low side service port located? near the compressor or ? High side port location doesn't matter.

JohnHere wrote: ↑Fri Jul 15, 2022 3:19 pm Correct me if I misunderstood. At first I think you mentioned a Sanden copy but later you mentioned a Denso compressor. Did you replace the former with the latter, or are they one and the same?

It's the Denso. 471-7031 and its a brand new compressor. I was mistaken—its NOT the Sanden. I never installed a Sanden, just the Denso.

Just a guess, but it's possible that an overcharge and/or inadequate oil amount damaged the compressor internally in some way, which is now causing the unusually elevated pressures on the low side. Is the compressor making any strange noises?

The compressor hardly makes any noise at all!

GottaBeCold88 wrote: ↑Fri Jul 15, 2022 10:15 am How did you determine how much refrigerant to charge? I just went off the gauges. This was my first time doing this. I think I way overcharged it as the gauges weren't changing as I filled. Suddenly the gauges spiked and the system started shaking. Then I shut down the motor, evacuated a significant amount of refrigerant (and oil with it) but unsure how much. I got a little freaked out. Gauges read what I think is normal now.

Again, I'm not an expert on aftermarket set-ups, but charging according to the gauge pressures alone doesn't tell us how much refrigerant is in the system now or how much to add/recover to achieve the optimum charge.

I mentioned earlier that an original 1993 van like yours with factory, front-only A/C, holds 44 ounces of R-12. This specification gives us at least some idea of the charge amount even though your custom system has different components and uses R-134a.

I would begin conservatively and charge 32 ounces of R-134a to start, dispensing the refrigerant into the low side from a 30-pound cylinder placed on a scale made for that purpose. I think the small 12-ounce cans will be too hard to deal with. After the initial charge and verifying the pressures, add refrigerant one ounce at a time while observing the pressures and vent temps until they just begin rising—and stop there. Doing that should result in very close to the optimum charge while minimizing the danger of overcharging.

DetroitAC wrote: ↑Fri Jul 15, 2022 3:23 pm Does the TXV have an adjustment screw you can see, or sometimes it's inside the low pressure port and can't access it while running, can you take a picture?

What is the temperature of the suction pipe (metal) near the compressor when it's running 1500RPM, high blower? thermometer insulated in great, put your fingers on it is ok too.

Where is the low side service port located? near the compressor or ? High side port location doesn't matter.

Heres the TXV:


No adjustment screw as far as I can see. The low pressure port doesnt have one either. I installed it on. custom-made hose. It's insline in the hose, about 6 inches of hose between it and the compressor.

I'll see if I can get the temp of the suction pipe today! Can I use an infrared thermometer? Or should I use the vent thermometer?

Thanks for all the replies, guys!

GottaBeCold88 wrote: ↑Sat Jul 16, 2022 11:13 am It's the Denso. 471-7031 and its a brand new compressor. I was mistaken—its NOT the Sanden. I never installed a Sanden, just the Denso.

An excellent compressor, as mentioned earlier.

GottaBeCold88 wrote: ↑Sat Jul 16, 2022 11:13 am The compressor hardly makes any noise at all!

A good sign that it's "healthy."

Infrared thermometer, calibrated finger, whatever works.

I meant the low pressure port of the TXV, it's in there trust me, but in order to adjust you have to recover charge and unscrew the fitting, let's hope it's adjusted close by the guys that made this unit.

So, there's ~12 feet of #10 size hose between the evap and the compressor? Service port is basically right at the compressor suction port?

The adjustment 'screw' if there is one is prolly buried beep in the port and usually have a female allen head. Turning CCW lowers the superheat ie allows more refrigerant through

12 feet is a long run for suction. Have to wonder if you could get anything larger thru the A pillar

OOps Detroit types faster

Have to ask, any chance condenser mounted upside down?
Fans running in correct direction?

Wonder if the manufacturer designed their evap to have such a long lineset. Did they by chance specify a max lineset length?

Okay responding to a lot of folks here:

• Got the temp of the suction port at the compressor. Temp with engine off and cold (but van sitting outside on a hot day) was 102*
  Temp with A/C running at max was 60*. (It felt cold and was sweating as well).

• I believe the length of the hose from the suction port is more like 8-10 ft. There doesn't seem to be any limit from the evap manufacturer.

• Not sure if the condenser is upside down or not! Didn't consider that. The discharge #8 hose goes to the top. At the bottom is the #6 hose which goes to the drier and then the evap.

• John-your recharge plan sounds logical. However, I don't want to use the 30lb tank as it's too expensive for me. Is there any way I can do it with the smaller cans?

Also, here are some more pics of my setup:

"The discharge hose goes to the top."

That is correct