Charging Air Conditioning System

[timsrv]

Update, I pulled my compressor clutch apart yesterday. There was oil on the "grabbing" surfaces and it was coming from the compressor shaft area. Oil here is bad as friction is required to make the clutch lock-up. So the question is........why is there oil here? In thinking about it I figured it had to be the oil mixed with the Freon that was there, and if that's the case I must be losing my Freon??? So I put a pressure gauge on the low pressure side (engine off) but I still have 80 psi.

When this happened it was the hottest day of the year (so far) @ ~ 105º F, so my working theory is perhaps after extended running at high temps, the pressure got extremely high and started leaking through the compressor shaft, then the clutch got wet with oil, the compressor stopped, the pressure dropped and it quit leaking. Speculation for sure, but it's the only thing that makes any sense. So I used some brake clean on the clutch "grabbing" surfaces and put it back together. AC is working fine again............but for how long???

I'll be ordering a new compressor today as I don't think this one is going to do it's job for much longer. Tim

PS: Scotty, I have no idea what that part number is. I typed it into a couple databases and came up with zilch. Exactly what part are you looking for?

[scotty]

compressor for an '87 4wd with dual AC. maybe i can find a number on the old one when i pull it out tomorrow.

[timsrv]

According to the EPC, the original compressor was Toyota part #88320-28090 and that's superseded by 88320-01011-84 (you were missing a 1). That would run you over $250 though, and it does not come with the clutch. My 86 2wd with dual air takes the exact same compressor. I just ordered this one: https://www.rockauto.com/en/moreinfo...1279751&jsn=12. It's a Denso rebuild with the clutch, and I assume it's just as good as the one you'd purchase from Toyota.

The one I'm running now (the one that's failing) I purchased off eBay and got the cheapest one they had (~$150). This time I decided to spend a little more and get the Denso unit (actually rebuilt by Denso) as I've had very good luck with their rebuilds in the past. Tim

[dogger562]

Tim, my compressor engages but it doesn't cool much.. I just want to get as much advice as I can before I spend more $.. when I install gauges I have way to much pressure on low side like 95psi and to low high side like 100 according to manual those readings indicate bad compressor.. Do you think I'm right??? If so I was thinking of rebuilding the extra compressor I have I was looking at some videos and it doesn't look that hard have you tried rebuilt kit from E-bay there like $25??? I did charge from front nipples and changed the dryer. Thanks

[timsrv]

That certainly sounds like a faulty compressor. I'm all for rebuilding components and I'm a little embarrassed to be swapping a complete unit. My core units all have over 200k miles on them though and it's already a big job to discharge, pull a vacuum, add oil, recharge, etc. Then there's the cost of the Freon (I'm still using the ultra expensive R12), so I can justify it. I'm thinking I can trust this new Denso one and $200 seems reasonable (to me).

If you're disassembling the pump and repairing yourself you'll need to invest in some special tools. Once apart you'll need to make sure all the internal hard parts are good. It's one thing to change soft parts on an old working unit, but I'd think twice about spending time and money on one that doesn't pump. Good luck. Tim

[dogger562]

Thanks, Tim yeah ill need ring pliers and that claw deal I seen a guy get away with a rubber hammer dough.. I'll see what I do its just ironic that I have like 40 cans of R12 and can't put one to use for me..LOL well at least I broke even from the ones I sold on Ebay

[scotty]

Looks good Tim, Thanks. I'll get one of those too. I figured I'd change the expansion valve too. Are there two for the dual AC system? It looks like RockAuto has a few options for my model van, and one specifies its for the front and other say they are for the coolbox?

[timsrv]

Depending on options there could be 3. The OE part numbers are as follows:

88515-87002 RR COOLER
88515-87003 COOL BOX
88515-87004 FR COOLER

Personally I'd leave them alone unless you're getting symptoms of a failure. It's been my experience these expansion valves are pretty reliable. It's the ones in the earlier Previas that were junk. Tim

[ratatouille]

Just about to order this compressor as well thanks for info Tim. Any tips/tricks for the process of swapping this out is greatly appreciated! Just got back into town from driving across state with temps hitting 118 at times! Ready to have my AC back.

[timsrv]

If I have some extra time I may take some pics and document the replacement/recharging. Tim

[timsrv]

Update: I installed this in my 86 van on Sunday. It fit perfectly and has been functioning flawlessly (so awesome to have good performing AC again). I was a little pressed for time, so I didn't document to the degree I hoped (I need a Go-Pro and some editing software). Here are the highlights:

Shaft seal failed on my old compressor and was leaking freon/oil out & into magnetic clutch. AC was still working but clutch would completely release/slip if RPM's were increased too rapidly. For the 2 weeks I lived with this I learned how to make it work. I would accelerate normally, then shift to neutral (allowing RPMs to return to idle), then pull it back into gear. It would maintain grip as long as I made gradual changes in RPM. If I accelerated hard enough to downshift, I'd need to "reset" again. This was okay for a while, but cooling was diminishing/issue was getting worse.

Evacuation: I evacuated system using an old R12 processing/recycling machine I found on craigslist .


This machine sucks freon out through system processing ports (using the valves on my gauge set), separates oil, runs it through a drier, then stores the freon in a tank. It has an accurate scale that keeps track of how much goes into the tank. Due to my blown seal I was only able to recover 2 lbs of freon (should have been 3 - 3.2 lbs). I recovered a little over 1 fl oz of oil while evacuating the system, then 1 oz more from the old compressor. Note: after removal, old compressor was set upside down over a drain pan, then rotated by hand to discharge oil. According to the manual, there should be a total of 2 - 3.4 fl oz of oil in the system.

Lubrication: The new compressor was supposed to have oil in it already (which it did), but the installation instructions did not say what kind of oil it was . This is important because R12 takes a different oil than R134A (and the two are not compatible). Denso's instructions did call out Denso 6 oil for R12 (as did the factor service manual) or Denso 8 for R134A conversions. Since I'm still using R12 I need Denso 6. To measure the amount of oil in the new compressor and to get rid of it (because I don't know what's in there), I removed the sealed shipping caps and set the compressor upside down in a drain pan. I slowly rotated it by hand to help discharge the oil. After it was done I collected and measured it to be 2 fl oz. After installing the compressor, I poured 2 fl oz of Denso 6 oil directly into an intake port before closing the system. Note: new compressor comes with new o-rings for the intake and outlet ports. I wet the new o-rings in compressor oil before installing them (this helps them to set and seal).


Deep Vacuum: Next I used my machine to pull a deep vacuum in the system and I let it run for 45 minutes. Note: FSM calls out 15 minutes minimum, but this is an older vehicle so I wanted it to be thorough. After 45 min I shut the service valves and monitored vacuum for another 15 minutes (this is to verify there's no big leaks). Note: for this level of service, it's a good idea to also replace the receiver/drier, but I just did that less than 3 years ago so I skipped it this time.


Charging: With a vacuum on the system, the pressure of liquid freon (~80 psi) is more than enough to force a full charge into it without starting or running the compressor (I prefer this method). To do this, I 1st attached a partial can of Denso 6 oil to my gauge set and used the vacuum in the system to suck the last fl oz out of the can, then I hooked my yellow gauge hose to a 30 lb cylinder of R12 and turned it upside down on a scale.


I set the tare weight to zero


By opening the high pressure valve on my gauge set, I allow the liquid freon to travel from the bottle and into the system. When the scale hit 3lbs 3.6 oz (3.225 lbs) I shut the valve. Note: I usually go slightly over what the book calls for because a little is lost in the hoses and a bit more is lost when disconnecting the gauge set.


Checking pressures and temps: After system has been charged and valves are all closed van is started and throttle locked at ~2k rpm. AC is turned on and fan set to max. A thermometer is inserted in the vent (air discharge) to monitor temperature. After 20 minutes low side pressure is recorded @ 28 psi and high side pressure is 175 psi.


According to the manual I should see low pressure side at 21 - 28 psi (good) and high pressure side at 206 - 213 psi (not so good). The service manual does not outline the scenario of normal pressure on low side and low pressure on high side, but it's 85 deg F outside and air blowing out my vents is 43 deg F (which is awesome), so I decided to ignore the lower than specified pressure on the high side (not much I can do about it anyhow).

Here's the box the new compressor came in (genuine Denso)




Here's a picture of my wasted magnetic clutch (note the oil and debris coming from the shaft area)



Note: This van is an 86 LE 2wd automatic with dual AC (no ice maker). Different years and/or options may have different specs than what I'm posting here. If you service your AC system I recommend using the Toyota Factory Service manual for your year of van and follow the specs for your specific model/options. Tim

[dogger562]

Nice, I'm going to do the exact same thing once i get my Denso compressor, good thing I have almost all the equipment dough I don't have the professional vacuum this one should do. I do have a question for all the HAVOC people. Is there a way to connect that vacuum/hose to a tank? Also ill post a pic of an 85 compressor part if any one ever needs it.

[timsrv]

If you're using R134A you can let it vent. If you're using R12, it's not only illegal, but damn expensive to throw it away. I have a very similar pump, but I think it's only capable of moving freon vapor. With that type of pump, I beleive you're supposed to evacuate the system 1st (let all the pressure out), then you can use that to pull your deep vacuum. I think it can handle the little bits of oil and what not that will go through it. Tim

[dogger562]

Of an 85

[dogger562]

Also, to throw my 2 cents in. I was told by an A/C shop that was going to charge me$300 to do the job that “75%" of leaking systems do so threw the port valves and recommends changing them if we don't know the history. I know I dint know what they were maybe will help someone else.

[ratatouille]

(I need a Go-Pro and some editing software)...

tim- ive got an old version gopro still works i dont use i can send your way if your seriuos about needing one to document van projects

- thanks for write up, just got my compressor in mail as well and ill see what i can also include here if anything . Ive got the 88 dual ac plus front fridge

[timsrv]

I'll PM you

[bigeo]

I had a local shop resurrect the AC on my 87 4wd van last summer and it worked through the hot times. At the beginning of this summer I turned it on and got warm air, not cold. Took it back to the shop and was told the rebuilt compressor that they had installed was not doing the job and needed to be replaced. This time, I ordered a Denso rebuild from Rock Auto and they installed it. It didn't fix the problem which turned out to be a stuck heater valve. After replacing the valve I got cold air for awhile and then not. The shop now tells me the condenser is leaking. I have been searching online for a condenser (do the 4wd dual systems use a different one then 2wds?) without any luck. Any suggestions? Also, I have a rebuilt compressor from O'reillys that probably is just fine that I would let go for a bargain price.

[timsrv]

Based on what you said, at this point I would have very little confidence in that shop & certainly would not trust their latest diagnosis. If you cannot do this yourself, I'd be looking for another shop to take it to. If you do indeed have a bad condenser, I would keep an eye out for salvage yard parts and/or "parting-out" posts on craigslist. Good luck. Tim

PS: Depending on where the condenser leak is, it may be reparable. Did they pinpoint the leak? Leaks are usually identified by putting dye into the system, then the leak(s) will usually become easy to spot. Tim

[dogger562]

I had a local shop resurrect the AC on my 87 4wd van last summer and it worked through the hot times. At the beginning of this summer I turned it on and got warm air, not cold. Took it back to the shop and was told the rebuilt compressor that they had installed was not doing the job and needed to be replaced. This time, I ordered a Denso rebuild from Rock Auto and they installed it. It didn't fix the problem which turned out to be a stuck heater valve. After replacing the valve I got cold air for awhile and then not. The shop now tells me the condenser is leaking. I have been searching online for a condenser (do the 4wd dual systems use a different one then 2wds?) without any luck. Any suggestions? Also, I have a rebuilt compressor from O'reillys that probably is just fine that I would let go for a bargain price.

Just P.M you