A/C Vacuum and Recharge

Reading the description of the "hybrid refrigerant" from your post, it apparently has oil in it already (along with leak sealer). At 28 bucks a can (10 ounces) it may have gold flakes in it also.

There should be a label in the engine compartment that has the exact refrigerant charge weight for a complete fill.

The manifold set should already have the correct fitting on the end of it's hose to attach to the top of the can. The manifold has all the ports and valves needed to pull the vacuum and then charge the refrigerant. The only reason to have the extra fitting for the can would be to save any unused portion I suppose.

Many times, if a AC system loses its charge very slowly, no oil is lost from the system. If you had a violent leak/evacuation, oil comes out with it. Very easy to tell because the oil doesn't evaporate/boil off and leaves quite the residue.

Pure R134a is available much cheaper at Wally World or Big Lots.

 

It is the oil that is hybrid specific, the refrigerant should just be R134a, but it must not contain any of the standard compressor oil. (The replacement cans are sometimes Refrigerant + Oil, to replace any oil that was lost in the leak.) Also, only use clean hoses/gauges that have never been used on a regular car, there may be contamination from the other car's system.

 

Here is an article about it: Hybrid vehicle air conditioning service

 

Thanks @ITBland ... out of a lot of A/C articles I've seen posted, that's an especially good one.

@red04prius, your first post mentions a vacuum pump you're thinking to purchase, but your link doesn't seem to go there, only to the gauge set.

You'll want to be an informed shopper there: pumps capable of reaching the level of vacuum needed for A/C work are quite specialized, and not inexpensive. They are also finicky about care and maintenance. Around seven benjamins is typically where I've seen them start, so it's tricky to make the case for a DIY purchase unless you are planning to DIY all your friends' air conditioners too.

-Chap

 

Chap,

When you click on that link, the vacuum pumps are on the right side of the screen. There's a 2.5 and a 3 cfm version. The 2.5 is advertised at $94 and the 3 is $149 more or less. Throw in one of the HF coupons and they're 20% less. I got the pump and gauge set for about $150, which was less than what it would have cost me to get a single recharge at a local shop.

I don't remember which model I have, I purchased it about 5 yrs ago when a family friend ran my 1995 right hand drive jeep straight into a tree and pushed everything back to the engine cooling fan/water pump. Had to replace everything on the front of the engine and forward. Surprisingly, the HF pump worked fantastic. It had some bad reviews, but most of them included comments about the pump blowing oil out the vent when it was running/trying to pull vacuum. What most people fail to realize is that means you still have a massive air leak in the system. The pump should only move "air" for a very short period, then there should be no significant "air" to move, just holding vacuum to let moisture boil off. If enough air is being pumped that it causes oil to come out the vent? ......well, you have some work to do on the system joints/etc.

 

Thanks, Chap!
On some of the other car forums, they are partial to the Harbor Freight cheapie vacuum pump for DIY repairs, inexpensive enough to use for one or two times, good enough to do the job. Personally, I'm a little uncomfortable with the idea of working on the A/C system on a hybrid, since the parts I might destroy are a lot more expensive than the usual auto A/C parts.
Edit: TMR-JWAP Beat me to it!!!

 

This is so damn funny. I was just reminiscing and read the one star reviews for the $94 pump. It smokes, it blows oil, it smokes and can't make a good vacuum, it maxes at 26", it maxes at 12". And half of them act as if they're ACnR know it alls....lol. I think one guy said he turned it on and nothing happened. That may be the only LEGIT bad review, as I'm sure that's happened a few times, as it can with any electrical item. But the rest? I'd bet anything they all still had leaks in the system they were trying to pull vacuum on, every one of them.

Here's one that really made me laugh....doesn't realize the motor is hot because it's drawing a ton of current since it's actually pumping air due to a leak instead of making vacuum. Couldn't put 2 and 2 together to recognize what's actually going on.....


SMOKEY JOE
By jd
This thing sure didn't work as a vacuume table pump. It spits out oil & smokes, plus it just doesn't create much vacuume. It might work as a AC vac, but not for any vacuume bags. Running for 30 min & the thing was sooooo hot! I doubt it pulls vac (75 micron) as advertised.

 

LOL! (also)

 

By golly, look at that, single stage and double stage rotary vane pumps for quite a lot less than I remembered from the last time I was looking around. Heck, for under $500 a person could even have a recovery unit and an empty tank to recover into! Hmm, still a bit salty for DIY for a thing you might use twice, but clearly coming down into the territory where a person who has trust issues with shops (who, me?) wouldn't find it impossible to be self-sufficient if it felt important enough.

(Chap steps away from keyboard thinking "hmm, when was the last time I wondered where my MVAC certificate was? Before moving to this address? Could be anywhere..." ... and actually finds it, a good part of the afternoon later. Glory be, they still used SSNs as certificate numbers back then. Wonder if they'd send me a new one with a distinct number....)

As for the inexpensive vacuum pumps, sometimes I do feel just fine using a low-end tool, if I also have a decent-quality instrument to confirm that the tool is doing what's advertised. It looks like decent micron gauges are fairly affordable now too. That would be a way to avoid having to just take the pump's marketing claims at face value, but ensure it really is bringing the system to an appropriately deep vacuum. And also to avoid vacuuming too deeply and changing the compressor oil composition.

Some references I've found useful in understanding what makes deep vacuum work interesting and challenging:

Slides from JB Industries on vacuum equipment for HVAC (with an emphasis on theirs, natch).

Article from Vac Aero International on oil-sealed rotary vane pumps, part 1, part 2.

-Chap