A/C servicing; vacuum, oil and charge system?

[2001LC]

I pick up both OEM Drier$78 and Denso Drier $22 (prices include tax)
Difference are first packaging:
Box Toyota vs Denso.
Sealed Warping of drier is High end/tech in Toyota, and looks made to last 100 years, Just plastic in the Denso box.

Because of the light proof warping of Toyota, I'm limited to feeling for difference, as I'll not be unsealing for this comprasson.

Edit: I did find a picture online that show it to be just the same as the Denso box. What a difference in price to have Toyota printed and different wrapping.

The Toyota feels as if it only has the longer plastic resin securing device. The Denso has longer device and the two piece with aluminum securing devices.

Toyota does not, nor does Denso have any marking as to manufacture visible other than on box.
Toyota box:

Denso Box:

 

[2001LC]

Also acquired the Denso oil, 3 cans (36oz which is just above minimum) of 134a, can tap. O-rings, manifold and vacuum pump (2 stage only unopened box HF had.)

Been cheaper to take to shop, but now I've the tools and hopefully a safe experience.

 

[white_lx]

Some random thoughts after repairing an A/C system in the weekend :

1. It is pretty difficult (at least here in our climate) to obtain the right air inlet temperature conditions for inspecting the refrigerant with a manifold. As per FSM: Temperature at the air inlet with the switch set at RECIRC is 30 - 35 °C (86 - 95 °F). So, I just filled to the right amount (by weight) and then verified the pressures. High Pressure was only about 60-70% of the FSM values at 18°C. Unfortunately, there is no table to correct the pressures for lower air inlet temperatures. As the system seemed to operate fine, I left it at that. So it might be easier to just fill to weight.

2. From my research: O-rings should be lubricated with mineral oil and not with refrigerant oil. The refrigerant oil is hygroscopic and will corrode the aluminum fittings. I also coated the fitting threads with some mineral oil. Might be helpful one day.

3. When you bleed the line from the schraeder valve on the manifold (or by loosening the fitting), put a rag or paper towel over the fitting as to not spray the refrigerant everywhere - especially when the manifold lines contain oil residue.

4. I can not believe that Mr T is not coating or lining these refrigerant lines to rear A/C systems. I am now 3-for-3 in having to repair (cap in this case) rear A/C's. The vehicle (LS430) that I worked on was extremely clean and rust-free underneath, but the rear A/C lines had pinholes from the road salt. Even a quick hardcoat anodize would be so much better than leaving them bare and it would have barely added cost. If anyone is replacing these lines, I would (epoxy) paint them before installing them and try to minimize the sponge action from the foam at each clamp.

 

[flintknapper]

Also acquired the Deso oil, 3 cans (36oz which is just above minimum) of 134a, can tap. O-rings, manifold and vacuum pump (2 stage only unopened box HF had.)

IF your vacuum pump did not come with pump oil, you are going to need some. Some auto parts stores carry it. If not...then your local A/C supply store will have it.

 

[flintknapper]

Some random thoughts after repairing an A/C system in the weekend :

1. It is pretty difficult (at least here in our climate) to obtain the right air inlet temperature conditions for inspecting the refrigerant with a manifold. As per FSM: Temperature at the air inlet with the switch set at RECIRC is 30 - 35 °C (86 - 95 °F). So, I just filled to the right amount (by weight) and then verified the pressures. High Pressure was only about 60-70% of the FSM values at 18°C. Unfortunately, there is no table to correct the pressures for lower air inlet temperatures. As the system seemed to operate fine, I left it at that. So it might be easier to just fill to weight.

2. From my research: O-rings should be lubricated with mineral oil and not with refrigerant oil. The refrigerant oil is hygroscopic and will corrode the aluminum fittings. I also coated the fitting threads with some mineral oil. Might be helpful one day.

3. When you bleed the line from the schraeder valve on the manifold (or by loosening the fitting), put a rag or power towel over the fitting as to not spray the refrigerant everywhere - especially when the manifold lines contain oil residue.

4. I can not believe that Mr T is not coating or lining these refrigerant lines to rear A/C systems. I am now 3-for-3 in having to repair (cap in this case) rear A/C's. The vehicle (LS430) that I worked on was extremely clean and rust-free underneath, but the rear A/C lines had pinholes from the road salt. Even a quick hardcoat anodize would be so much better than leaving them bare and it would have barely added cost. If anyone is replacing these lines, I would (epoxy) paint them before installing them and try to minimize the sponge action from the foam at each clamp.

The best thing to do with O-rings is to purchase a bottle of 'Nylog'. Use it on both O-rings and the fitting surfaces. You will not have a leak at that point again.

 

[2001LC]

IF your vacuum pump did not come with pump oil, you are going to need some. Some auto parts stores carry it. If not...then your local A/C supply store will have it.

Thanks. I don't see listed on the outside of box (haven't opened yet) so I suspect it's not included. Nice catch!

 

[white_lx]

One more thought: at higher elevations your maximum vacuum will be less than 30 in-Hg.

Rule of thumb: for every 1000 feet above sea level, the maximum possible vacuum is reduced by approximately one in-Hg.

 

[2001LC]

Good to know, thanks. So I'll be looking for 24.75 in-hg as my high mark, in the mile high city.

 

[2001LC]

So I replaced the Dryer with Denso and the 2007 uses the larger single piece plug. I couldn't find a torque spec so just snug up plus a little after I felt resistance from O-ring seating. The old plug was a little oily, so I oiled the New O-ring that came with it and cover the plug screen with oil.

The bottom of old Dryer was oily, so I also oiled new a little bit too.

I had removed the discharge tube at condenser and the return line at compressor. So added some oil to compressor (3/4 oz) and some into discharge tube (3/4 oz). I replaced both O-ring with new OEM O-rings after oiling them. In all I added 1 3/4 oz (~4 TLBS) which is about double what I lost.

 

[2001LC]

I've gotten to the point that it's time to charge the AC. Out of concern (right or wrong) from the FSM statement "do not run engine with AC system empty. That even with AC off it can damage compressor."

So my plan is to hook up vacuum pump and run for 30 minutes, and look for it to draw ~-24.75 in-hg with H & L open.
Close H & L, turn off pump, watching for next two hours for any drop in neg vacuum.
Then continuing vacuuming for minimum of two hours with H & L open, also keeping eye on vacuum.
If no leaks I'll move to filling:
I'm going to add at least two of my three 12oz cans into H with engine off. I'll do this by holding can upside down with only H side open.

Then come back and third can into L after I start the engine with H closed. This will be after I do some other (first engine) start-up stuff like transmission fluid flush etc....

Does this sound like a good plan?

 

[nissanh]

When adding the can should switch 12 O clock and 3 O clock positions (double check). Holding up side down will let the liquid form of freon to enter the compressor and it is not good for the compressor pistons.

I though you must add gas to low side only with engine running, I might be wrong and tell me why there is a port on high side.

When engine is running and AC off, only the clutch pully is spinning so it shouldn't harm the componenets of the AC compressor. Compressor lubricant is there to lubricate the AC compressor.

When you are adding gas, you should keep doors open to keep the compressor running. I fill until the window located on the high pressure side line (located below the driver side headlight) clears up. Little bubbling is ok, but not a lot. As soon as the AC compressor turns off, you should see bubbles within 2-4 seconds and should be clear as soon as the compressor kicks on.

 

[flintknapper]

I've gotten to the point that it's time to charge the AC. Out of concern (right or wrong) from the FSM statement "do not run engine with AC system empty. That even with AC off it can damage compressor."

So my plan is to hook up vacuum pump and run for 30 and look for it to draw ~-24.75 in-hg with H & L open.
Correct, you want both H&L sides open when pulling a vacuum. The degree to which you can pull a deep vacuum will be dependent on your elevation. Be sure to have NEW vacuum pump oil in your pump and that you understand how to use the pump.


Close H & L, turn off pump, watching for next two hours for any drop in neg vacuum.
Correct, close the H&L valves on the A/C manifold set BEFORE turning off the vacuum pump. No need to wait 2 hours. IF you have no 'significant' drop in vacuum in 30 minutes you should be fine. IF the system is properly sealed you likely will see no discernible movement of the needle. Even if it drops a very small amount, no need to worry. You are looking for an obvious loss of vacuum...which of course points to a leak in the system.


Then continuing vacuuming for minimum of two hours with H & L open, also keeping eye on vacuum.
Correct, the reason for pulling a 'deep' vacuum over a long period of time is to remove as much moisture from the system as is possible. It is NOT to try to get the last smidgen of Hg....but rather to give the moisture time to 'boil off' and be extracted. I consider two hours the minimum for a system that has been open for a period of time.


If no leaks I'll move to filling:
I'm going to add at least two of my three 12oz cans into H with engine off. I'll do this by holding can upside down with only H side open.
Yes, if you plan to Liquid Charge Into The High Side Under Vacuum. BUT....I doubt you will get two cans into the system that way and ONE can is sufficient to provide enough pressure to kick in your compressor when you go to the low side to complete the charging. The advantage of first charging into the high side (engine OFF, system under vacuum) is that it speeds things up, it provides pressure for immediate start up of the compressor and it provides enough refrigerant to start carrying the lubricating oil through the system right from the start.

So yes, in order to 'liquid charge' you will invert the can (relative to where you have pierced it/can tap). The process doesn't take long. Usually not more than a minute. You will feel the can get cold and the can will feel empty in the hand (weight). You are then done and can close the high side valve. You will NOT be going back to the high side from this point forward.

Then come back and third can into L after I start the engine with H closed. This will after I do some other (first engine) start-up stuff like transmission fluid flush etc....

The remaining cans (we are really looking to 'weigh in' the charge) will be introduced though the Low Side port in a gaseous (NOT LIQUID) state, so the keep the can upright. Engine running, HIGH SIDE OFF, low side open, compressor running, A/C set on high. This will be a slower process and you don't want your low side valve completely open at this point. Just open it enough that you see the pressure rise (it might jump around a bit) to no more than 60-80 psi. It will drop some as the system stabilizes.

The last can (as you approach the recommended weighted amount) will be the one that will take the longest and might even require tilting it slightly (just momentarily) to get it to go in (depending upon ambient temps). You can get away with letting only SMALL amounts of liquid refrigerant go into the low side, but be aware...too much can 'slug' your compressor. You may need to have your low side valve completely open for this last step (watch your gauge).


Does this sound like a good plan?
It's fine. There are a couple of ways to charge a system, both acceptable.

NOTE: There are a few nuances that have not been discussed that are practiced by folks who do this regularly that might not cross the mind of the novice.

After all your hard work preparing the system to be leak free, we DON'T want to introduce any air back into the system. So be very careful to understand WHEN to shut off (or open) which valves and ALWAYS 'purge' your lines when adding refrigerant.


And lastly:

Don't expect (and then ultimately be disappointed) any certain 'benchmark' vent temperature UNLESS all your components are brand new. There are too many variables (condition of parts) one vehicle to the next for you to expect to have 40° F. at your vents (Hot summer day)...just because 'so and so' on the MUD forum does.

A 'reasonable' figure will be 30°F below ambient. If you get more than that (and many do) then great. But don't automatically suspect something has gone wrong if you don't get ice particles blowing from your vents.

^^^^^^ Expand for replies (long read).

 

[flintknapper]

When adding the can should switch 12 O clock and 3 O clock positions (double check). Holding up side down will let the liquid form of freon to enter the compressor and it is not good for the compressor pistons.

He is planning on Liquid Charging the High Side INTO VACUUM (engine off) to start with. A commonly used practice among professionals. Then finishing the charge through the low side in gaseous state.

I though you must add gas to low side only with engine running, I might be wrong and tell me why there is a port on high side.

Yes, DO NOT charge 'liquid' refrigerant though the low side (though in reality it is necessary to introduce SMALL amounts that way) to finish charging the system in some cases. Depends on the ambient temperature and whether or not you have a way to heat the can/container.

When engine is running and AC off, only the clutch pully is spinning so it shouldn't harm the componenets of the AC compressor. Compressor lubricant is there to lubricate the AC compressor.

Yes, BUT the only way the oil can be distributed is to be carried by the refrigerant. However...you are correct to say that no damage will occur provided the compressor is not running. So if there is any concern...simply disconnect the connector (12v source) at the compressor and no accidental engagement is possible.



When you are adding gas, you should keep doors open to keep the compressor running. I fill until the window located on the high pressure side line (located below the driver side headlight) clears up. Little bubbling is ok, but not a lot. As soon as the AC compressor turns off, you should see bubbles within 2-4 seconds and should be clear as soon as the compressor kicks on.

There are several conditions that can result in bubbling/foaming or a clear sight glass, some good... some bad.

IF you don't have a manifold gauge set and are somewhere out in BFE...that method provides a remedial way to judge the flow/charge of refrigerant. Use gauges always...if you have them.

^^^^^ Expand for reply

 

[2001LC]

^^^^^^ Expand for replies (long read).

That is such a great reply, thank you so much for taking the the Time. You, @white_lx, @nissanh and @medtro have been invaluable in teaching me how to do this first for me.

Thank you all.

I'll keep posting progress as I go.

 

[TXSunDevil]

The only recommendation I would make is after adding the 2 cans while the system is in a vacuum wait a few minutes before staring the engine. You will be dumping liquid refrigerant into the system and you do not want the compressor to try to start pumping liquid. If you give it time to settle and equalize you have less of a chance of slugging the compressor.

 

[2001LC]

Thanks, good advice. I'll just start with 1 can in H, than two in L after starting while running.

 

[flintknapper]

Thanks, good advice. I'll just start with 1 can in H, than two in L after starting while running.

Let us know if you need any help. Don't be afraid to ask questions. The first time you recharge a system (correctly) can be a little daunting, but really is just a matter of going slowly and doing things in the correct order.

Your reward (nice cool air and a long running system) will be satisfying. Plus... you will have the tools for any future work (or helping others) already on hand.

 

[2001LC]

HELP!.

Well day didn't go well. Which I'll tell you all about it in a moment. But first is there a test to make sure the AC manifold tool itself is not leaking?

With vacuum pump running drawing ~22 in-hg I closing the H & L attached to AC system of vehicle, then closed H & L on the manifold and -22in-hg went to 0 fast.

 

[TXSunDevil]

I closing the H & L attached to AC system of vehicle, then closed H & L on the manifold and -22in-hg went to 0 fast.

I am confused here. Are there valves on the hoses you are closing or are you closing the side handles on the manifold. If you are closing the manifold gauges your hoses should be reading system pressure. If the vacuum pump had been running the system should be in a vacuum. If it goes to 0 that means there is a leak somewhere in the system. Did you pressurize it first with nitrogen to check for leaks? A leak can be anywhere in the system from the hose connection to the manifold to anywhere in the ac tubing. Ideally you leak check with positive pressure in the system. Something that goes from 22 inches of mercury to 0 in a hurry is probably a good sized leak that you can hear when pressured up. If you want to check the manifold hoses here is what I would do. Disconnect the manifold from the system. Close all the handles. Attach the refrigerant cylinder to the hose and open. Your gauge should read pressure. Use soap bubbles on the joints to look for leaks. Once that hose is done you can move to the other side and then finally the service hose.

 

[flintknapper]

I'm not quite following your valve closure procedure. Do you have ball valves on your hose set in addition to the valves on the manifold?

IF no mishap with the hoses or connections occurred...then you have a significant leak somewhere in the system or you failed to pull a vacuum to begin with.

Might be best if you explain the process you used to connect the pump and vacuum the system. Its easy to forget to open a valve...or to over tighten a hose connector and crush the seal (sealing off the hose from its port). Little things that can trip you up.

If you suspect a possible leak in the A/C systems components....you'll need to pressurize it.