Automotive Air Conditioning Information Forum

DetroitAC wrote: ↑Fri Jul 16, 2021 12:42 pm I've never seen a Denso scroll pulley driven, didn't know that was even a thing, seems like Sanden would have been the OEM version?

I know Honda used both brands over the years. I'm not sure there's much difference in quality, but I'm no expert. I'm not certain the Denso is a scroll either, but it's shaped exactly like the original one. I always thought the piston compressors had "heads" on them, like a mini 4 cylinder radial engine, which this one definitely doesn't have.

I'm a bit over half way through this job and have a couple impressions so far. First is that when i flushed the evap with the TXV out this time, a ton of oil came out, as compared to when i 'flushed' with the TXV left in last time. This makes me think that same amount of oil was left in there before, so, with the 3oz in the new compressor, plus the 3 more i added, there was probably ~2-3 oz excess oil in the system. Everything I've read says the symptoms of excess oil are poor cooling and high system pressures. At any rate, all of the oil was removed, and i weighed in 6.5oz, so if there are still problems, it won be due to excess oil.

Second thing is i was skeptical about the vacuum pump oil, but sure enough, the needle on my gauge is hovering a hair away from 30" now with fresh pump oil in there. So thanks to @tbirdtbird for this tip!

I had to leave to tend to some other business, but i left the system under vacuum (pump off and valves closed) to see if it holds. I should be back at this in about an hour, so I'll post my results.

Harry Seaward wrote: ↑Sat Jul 17, 2021 10:33 am At any rate, all of the oil was removed, and i weighed in 6.5oz, so if there are still problems, it won be due to excess oil.

Better double-check that oil amount before you button everything up because you still might have a big problem. Unlike a refrigerant charge, the oil amount is measured in fluid ounces, not by ounces of weight.

To solve the oil problem, I think what I would do is at the workbench, weigh another 6.5 ounces of oil in a suitable container and pour it into a graduated beaker to determine how many fluid ounces of oil you actually put in. Hopefully, both measurements will be very close. If not, you'll need to add or remove oil to arrive at the correct amount.

Good call, John.
For more info....
http://www.differencebetween.net/scienc ... nd-ounces/

From YJ on pump oil (some techs change it every job):
"Because vacuum pumps don’t have filters, the oil inside becomes saturated with contaminants, which reduces the pump’s efficiency. Once oil is saturated it can’t absorb any more system moisture. If the oil becomes contaminated, it eventually turns into a sludge, which greatly reduces the pump’s efficiency. Oil that is both contaminated and saturated doesn’t lubricate well and can quickly wear out the pumping apparatus."

JohnHere wrote: ↑Sat Jul 17, 2021 12:12 pm

Harry Seaward wrote: ↑Sat Jul 17, 2021 10:33 am At any rate, all of the oil was removed, and i weighed in 6.5oz, so if there are still problems, it won be due to excess oil.

Better double-check that oil amount before you button everything up because you still might have a big problem. Unlike a refrigerant charge, the oil amount is measured in fluid ounces, not by ounces of weight.

I didn't see this in time, and don't really have anything to get that precise of a measurement anyway. The compressor has a 1/3 fl-oz range on the stated capacity and the shop manual says 1/3 fl-oz for "each line and hose". That seems to be a bit loosy-goosey considering some lines and hoses are twice the length and diameter as others. Hopefully PAG46 is +/- 1 fl-oz volume at 6.5oz weight.

Everything is back together and functioning. I noticed that the condenser fan didn't seem to be blowing very hard, so I replaced that while I had everything apart. The low side is lower, but the fan didn't make any difference on high side temps.
Here's the data:
105 degrees ambient and 33% humidity (humidity based on weather.com for my area)
1500 RPM
40psi low side, 325 psi high side (see below).
Condenser inlet is 178 degrees, outlet is 150 degrees on the flat part of the pipe side of the fittings - I used a digital meat thermometer that gives perfect 130 degree readings on my medium-rare steaks.
Using same thermometer, vent temp is 65 degrees at 1,500 rpm in my 105 degree garage. It dropped to 55 on the 30 minute drive to return the car to my daughter at 4:30pm.
It's condensing water like crazy - the low pressure line with the service port was pretty cold and coated with pretty good sized beads of water, and the evap drain tube was dripping about every 1/2 second sitting in my garage at 1,500 RPM. It's just not blowing as cold as I remember. And maybe I'm thinking of times when it was 5% humidity, who knows. I know the humidity kills the efficiency. My daughter's boyfriend said it got down below 40 on the freeway a couple days ago. If I had known that, I probably wouldn't have torn into it again today.

I've determined that my expectations are just too high, because on the return trip in my wife's '16 Pilot her vent temp was only 51. Something that is odd to me, this video (https://drive.google.com/file/d/1A2YUEp ... sp=sharing) shows the gauges fluctuating, and I noticed that the vent temps would also fluctuate, although I couldn't see the gauges and the vent temp at the same time, so I don't know if it was a direct correlation between the two. Anyway, I've had gauges on this car at least 20 times, and I have never seen it do this. I seemed to remember that this was possibly an indication of moisture (or air?) in the system, so as impossible as that seemed, I vac'ed yet again to 29" and recharged, but the fluctuation returned. It didn't seem to do it until right at the end of the first 12oz can. I'm guessing this is something related to the new TXV, even though I had installed the exact same brand of TXV two-ish weeks before the one I just put in today. It did settle down to about 1/4 of the fluctuation seen in that video once I got it fully charged and let it run about 10 minutes, but it still moves around like I have never seen.

So that's where I'm at. It what it is. There's no leaks and it's blowing 'cool'. I'm anxious to see how it does when we get back down to our normal humidity range out here.

Note to future self: don't forget to reconnect the transmission cooler line so you don't pump 3 quarts of fluid on the ground.

The factory data that I have for your 2007 CR-V specify 18 ounces of R-134a and 4.5 ounces of PAG-46. You mentioned earlier that you charged it with 16 ounces of R-134a and approximately 6.5 ounces of PAG, maybe more. If the specs I have are accurate, it's undercharged by two ounces, and it still has too much oil in it.

JohnHere wrote: ↑Sat Jul 17, 2021 9:33 pm The factory data that I have for your 2007 CR-V specify 18 ounces of R-134a and 4.5 ounces of PAG-46. You mentioned earlier that you charged it with 16 ounces of R-134a and approximately 6.5 ounces of PAG, maybe more. If the specs I have are accurate, it's undercharged by two ounces, and it still has too much oil in it.

I'm looking at the Honda shop manual and sticker under the hood.
https://drive.google.com/file/d/12t-KdO ... sp=sharing
The sticker under the hood says 15.5-17.9 for 134a. I went 16 since that fit nicely within both ranges.

For the oil, I have 3 lines and hoses, unless you count unions; in which case I have 4. 3 + 1.667 + 1.334 + (.334 * 3) = 7(.003)

Al9 wrote: ↑Sun Jul 18, 2021 4:17 am Warm air could be making it around the evaporator due to rotten air dams...

Yeah, interestingly, this car never had dams between the condenser and radiator. There's just a ~1" gap between the two and it's wide open on the top and sides. The bottom has the metal tray they both share. I suppose the bumper/grill are supposed to function to shape the air flow, but there's no physical barrier at the gap.

" There's just a ~1" gap between the two and it's wide open on the top and sides"
WOW!!
That is the equivalent of an AC mile.
I would get some foam strips in there and you will see a big difference.
I was about to ask you to use a garden hose and mist down the condenser but this huge gap is def part of your problem
Foam=cheap and easy

When we do custom installs we always mount the cond. no further away than 3/8 inch

I have never seen a factory install with that much of a gap.
Wonder if the original cond. had a diff. configuration than the replacements
Also, we do not worry about calculating oil/hose, regardless of the manual you have.
If there is a total specified amount of oil in the manual then we use it.
Otherwise on a custom or unknown job we use the rule of thumb of 8 fl oz total (we use 3 oz dixie cups to measure, no graduated cylinders here tho that would be super ideal). We distribute that as 2 oz each per comp, evap, cond, and drier before we assemble the components. I will be doing a custom install soon and that is how we were taught by the pros that taught us.

Is there also a mechanical fan on this motor?

I think Al was referring to the air seals around the evaporator. Regardless, I've seen a number of vehicles that lack any kind of seals between the condenser and radiator and have a large gap, as you mentioned, and they seem to work just fine...my own cars included. Others I've seen are sealed all around. Just the way the airflow path is designed.