A/C pressure test

[g300d]

Denso on the pre facelift, Calsonic Kansei on the facelifts.

Both variable displacement models.

[upallnight]

Originally Posted by Csaviano

Here are the new test results. Keeps in mind the aux fan never came on
1) Engine off - high was 70 and low 69
2) engine on compressor/aux fan not on - high side was 155 and low side 32
3) engine on with compressor engaged by me - high side was 115 and low side 64
4) engine on with compressor disengaged (on its own) high side 100 and low side 69

I ran the car for a few minutes and as mentioned above. the compressor/clutch disengaged on its own and didn't come back on. I forced the compressor to come on by hooking it up straight to the battery source.

You must be doing something WRONG. With the engine on and the compressor and fan OFF there shouldn't be that great of a high side low side pressure differential. If the compressor is not engaged the pressure on high and low should be the same as the 1. reading.

[upallnight]

Originally Posted by Csaviano

Here are the new test results. Keeps in mind the aux fan never came on
1) Engine off - high was 70 and low 69
2) engine on compressor/aux fan not on - high side was 155 and low side 32
3) engine on with compressor engaged by me - high side was 115 and low side 64
4) engine on with compressor disengaged (on its own) high side 100 and low side 69

I ran the car for a few minutes and as mentioned above. the compressor/clutch disengaged on its own and didn't come back on. I forced the compressor to come on by hooking it up straight to the battery source.

I assume that the compressor was engaged when you turn the AC on from inside the car and afterward, the compressor disengaged by itself. Afterward when the compressor wouldn't re-engage you went and jumped the compressor.

As for the reading that you obtain, I believe that for 2. the compressor had to be engaged in order for you to obtain those readings. Do you know what the vent air temperature was when you did the test for no.2? The high side reading is low, but the low side reading is waaaaaaaaaaay to low. With the low side reading being 32 psi it means the temp from the vent will be close to freezing which is not the intended design. The problem with the vent temp being that low is that hot moist air in the summer will condense on the evaporator and with the water on the evaporator, the water will freeze, blocking air flow through the evaporator. A good low pressure reading should be 36-45 psi depending on the ambient temp.

Best advice you got from other posters was to take it in and let someone with knowledge on how to troubleshoot and fix the ac system.

There are certain procedures that must be followed when you go to add refrigerant back into the system, which from reading your post it doesn't appears that you are following them.

[David.X5]

This is sort of dead, but just wanted to post this info for the next person. I looked up the Denso part numbers for the pre-facelift 4.4L , and this is what their website says.

Type 10S are Reciprocating, Dual Swash Plate, fixed displacement
Fits pre-facelift 4.4L E53 X5
Denso Part Number 471-1380
Type 10S17C

[g300d]

^Ah, I've thought for the longest time the Denso's were also variable displacement, my mistake. Thanks for sharing the info!

To add to the data, facelift 3.0 gas models use the Calsonic Kansei CSV 717 variable displacement compressors.

[Csaviano]

Dear friends. This is an update

Took the car to an Indy shop to have ac whooped at. After $100 they told me I have a wiring issue and it will be at least 3 more hours to diagnose the problem. Then they listed all other things that were wrong with it unrelated to the ac and concluded I should consider trading my baby in. Well, here I am with no a/c and with my baby in my garage.

I have power to the fan and to the compressor. On the inside, the ac max or the seat warmers switches Are functional. However the couple of time the ac started working while driving down the road, the ac max and seat warmer switches became functional. Any hints?

[David.X5]

That stinks. Electrical gremlins can be a time and money sink. Is the blower inside the car working? When the special resistor for the blower fan speed goes bad, The AC can get wonky. But you will usually have problems related to the blower - like it stays on when you turn the car off.

I think you started this by saying you replaced the AC fan (engine compartment one). Was that a known brand or a generic? Have you changed any other electrical parts or done anything else where you disconnected wiring harnesses, etc.?

[Csaviano]

Yes blower inside the car works. I replaced the pusher fan with generic brand but at a couple of points it did work.
To the pusher fan there a small blk green wire. I traced it from the fan to the dme and it had connectivity but none from the dme to the control panel.

[upallnight]

Originally Posted by Csaviano

Great David. Thank you for your help. I will take it to a mechanic at this point. On the flip side I did learn how to use gauges and and now know more about the a/c system.

When you borrow the gauges from auto zone, after you connected the lines from the gauges to the bayonet fittings in the engine compartment, did you open the valves to the lines?