Do it yourself AC recharge?

[T Bolen]

I was in an auto parts store recently and noticed they are selling a kit complete with hoses, gauge, and refrigerant to do a recharge at home. Anybody try one of these?
My '95 needs a recharge and I hate to take it to most shops. Prefer to do it myself if I can.
Would appreciate hearing from anyone who has had any experience with these kits.
Thanks in advance.

 

[Soichiro]

If you are certain that all you need is refrigerant you can do this at home easily. The NSX has a sight glass that displays bubbles when low on refrigerant. Add only until the bubbles disappear. Don't overfill, that is bad for the system. Get some pressure gauges or take it to a shop if you want to find out the condition of the entire system.

 

[nsxtasy]

I would NOT recommend doing the recharge at home. If your car needs a recharge, it has a leak. Dealer service departments and independent professional mechanics have equipment (dyes and "sniffers") that they can use to find the leak and fix it before recharging your system. If you don't do this, your refrigerant will simply leak out again. Furthermore, professional mechanics have equipment that recovers and recycles the refrigerant that is already in your car and makes sure that no refrigerant is lost during the charging process, which is good for the environment and saves you money, too.

 

[Soichiro]

Ken makes good points about leaks and the environment. If you decide to do it yourself there are devices that inject the flourescent dye with the refrigerant so (if you purchase a UV inspection lamp) you can find the leak yourself. I guess you could also purchase a sniffer and find it that way. I've been told the sniffers are much better (find smaller leaks quicker) than the dye method.

 

[MiamieNeSeX]

The system has many mechanical connections as opposed to welded connections on the refrigerant circuit. So if your car needs a recharge the leak might be to small to detect. If you do decide to charge the system using the sight glass, make sure you do it slowly and preferably in the shade to keep the head pressure down.

 

[T Bolen]

Yea, I am very much aware of the possibility of a leak. Being R134A refigerant, it is not supposed to be bad for the ozone.

Remember, the question is has anyone done this and if so was it successful?

 

[MiamieNeSeX]

If you clear the sight glass slowly you should be ok.

 

[T Bolen]

Thanks MiamieNeSeX! The kit I've seen has a safety gauge that (they claim) allows for accurate charging.

 

[coos]

using the sight glass?

Using the sight glass is not always the best way of doing it. They have taken out the sight glasses in most cars because of miss diagnostics. Bubble's don't always indicate low refrigerant, besides a/c systems are pretty tempermental, a few oz. off and the a/c will not be as cool as it should. I would not trust myself to do a recharge with out a machine.

 

[dlongo]

I've done the DIY recharge using those kits, but only on beater cars I don't really care about fixing right. For the NSX I wouldn't do it, I agree with others here that you should take it for a leak check.

 

[1BADNSX]

Most of these new kits include an inline pressure guage. It seems it would be very easy at home to fill to the proper level if you know the correct low side operating pressure. Does anybody know?

Bob

 

[MiamieNeSeX]

Most of these new kits include an inline pressure guage. It seems it would be very easy at home to fill to the proper level if you know the correct low side operating pressure. Does anybody know?

Bob

There is no precise pressure as there are to many variables, cockpit temperature, ambient temperature and so on, both using the sight glass and watching the suction line for coldness and condensation will work just fine. But if you want to throw your money away and have a tech do it using the same methods go right ahead

 

[1BADNSX]

There is no precise pressure as there are to many variables, cockpit temperature, ambiaent temperature and so on, both using the sight glass and watching the suction line for coldness and condensation will work just fine.

You are correct, but the service manual gives a nice graph that shows the expected low side pressure. For instance, with an outside temperature of 86F, the low side pressure should be between 34 and 43 psi.

The new over-the-counter refill kits have built-in pressure guages. I find them nice just to check the status of the system. If the pressure gets low in the NSX, it can toast the compressor which is a very expensive job. Consider it preventative maintenance.

Bob

 

[MiamieNeSeX]

You are correct, but the service manual gives a nice graph that shows the expected low side pressure. For instance, with an outside temperature of 86F, the low side pressure should be between 34 and 43 psi.

The new over-the-counter refill kits have built-in pressure guages. I find them nice just to check the status of the system. If the pressure gets low in the NSX, it can toast the compressor which is a very expensive job. Consider it preventative maintenance.

Bob

The system has both low and high pressure cut outs that will shut the compressor down. Remember the graphs are based on perfect conditions including clean evaporator and condenser coils, charging the system is not as difficult as most people make it out to be. I have been in the refrigeration business for many years.......... knowing the basics charging an a/c system is very simple good luck

 

[silverNEEK]

Correct me if i am wrong but I have been told that if you change a freon system to a R134A refigerant type system the sight glass becomes of no use. Am i wrong? Can anyone who has performed the conversion please opine.

 

[MiamieNeSeX]

Correct me if i am wrong but I have been told that if you change a freon system to a R134A refigerant type system the sight glass becomes of no use. Am i wrong? Can anyone who has performed the conversion please opine.

Wrong

Sight glass will still be helpfull

 

[T Bolen]

Correct me if i am wrong but I have been told that if you change a freon system to a R134A refigerant type system the sight glass becomes of no use. Am i wrong? Can anyone who has performed the conversion please opine.

My car is a '95 and came from the factory with R134A. The sight glass is clearly showing bubbles and the air is warmer on the driver's side. I must conclude that the sight glass is doing it's thing for the R134A.

 

[JGuidry]

DIY It's easy.

I have a slow leak that requires recharge about every 6 months.

I find its a "no brainer" to spend $10 twice a year to recharge instead of $2000 to fix.

It's real easy, Just make sure you recharge the low side.
44PSI on the low side with 134a is what the NSX tech here in Houston told me. It works every time, and only takes 10-15 minutes.

Jonathan

 

[Bart Geerts]

The system has both low and high pressure cut outs that will shut the compressor down. Remember the graphs are based on perfect conditions including clean evaporator and condenser coils, charging the system is not as difficult as most people make it out to be. I have been in the refrigeration business for many years.......... knowing the basics charging an a/c system is very simple good luck

In aviation-maintenace it's standard procedure to change the receiver/dryer every time you refill the refrigerant? Should I do this with the NSX ??
Thx in advance,

 

[D'Ecosse]

Welcome to Prime - congratulations on your first post!
It should not be necessary to replace the receiver/dryer - that is recommended however if you replace the compressor.
The question everyone should ask is "why does it need to be charged?" if it is a very slow leak, as in the case mentioned by JGuidry, then maybe its OK to just refill once in a while - this is pretty much not an option for the R12 guys, however - unless they convert, which may still be a good option. I would recommend having a shop look for the leak - it does not necessarily mean a "$2K repair" - may be as simple as one of the schraeder-type valves leaking. An A/C shop can test the system to find the source, then you can make a decsion from there.

 

[Bart Geerts]

Welcome to Prime - congratulations on your first post!
It should not be necessary to replace the receiver/dryer - that is recommended however if you replace the compressor.
The question everyone should ask is "why does it need to be charged?" if it is a very slow leak, as in the case mentioned by JGuidry, then maybe its OK to just refill once in a while - this is pretty much not an option for the R12 guys, however - unless they convert, which may still be a good option. I would recommend having a shop look for the leak - it does not necessarily mean a "$2K repair" - may be as simple as one of the schraeder-type valves leaking. An A/C shop can test the system to find the source, then you can make a decsion from there.

I'm a new owner, I only bought the NSX yesterday. I exchanged it for a 2001 S2000. It was my opinion that the NSX would keep it's value more easily than the S2000. I have to get used to the small pedal-area...

 

[T Bolen]

Update - I finally did it!

Well, after 6 months of semi - air conditioning I tried the DIY kit. Went to Pep Boys and spent $35 on their recharge kit. Found it very easy to use and the whole job including the learning curve took me 20 minutes! Now the AC is really freezing me out.
The important part is finding the low pressure fill port. The instructions were pretty helpful, but it did take me a while to find it. Tip - it is located on the larger refrigerant line close to the firewall just below and to the left of the brake booster (as you face the front of the car). And, typical Honda engineering, it had a protective cap labled "L". Kinda makes it easy.
I encourage anyone to give this a try if their system is low - now that I have the kit with the fittings, future refills are just $10-$12 for the refrigerant.

 

[patrickseto]

Hello T bolen,

Recharging the R-134a system is not hard at all as long as you don't overcharging it. R-134a systems run under a higher pressure than old school R-12, hence less efficient; and, they prone to leak more - with smaller molecules (R-134a). Anyway, remember this:

Never, ever put in or charge your system with the so-called sealant kit w/reconditioner from WalMart or other aftermarket parts stores, they will eventually clog up your compressor when you inject that chemicals (2 bottles) from your low side into your A/C system. We had our shop (we are a Toyota dealer) RobinAir machine down for more than 2 weeks, lost at least 1 week worth of A/C jobs (had to re-schedule) for this particular reason...

I was acknowledge by our NAPA store after they sent the machine back to RobinAir for us, couple days later, a report (in fact, a book full of accusations) came back from RobinAir telling us it's out of warranty and it's non-warrantiable, no good-will will be honored... it's our fault and we had to bite the bullet and eat it! Guess what, we purchased another machine from Lark thereafter...

About 1 week later, the A/C compressor on customer's car quit working too... Of course we had to pay for fix it...

NAPA stores do sell a test kit now to detect if your vehicle has already had sealant in it or not. It can also be performed right in front of the customers by taking a few easy steps. If test result turns out to be positive, means your system does have sealant in it, you have to pay the shop their diagnostic fee plus the charge for the test chemicals, probably around 30 bucks and they won't fix your A/C at all... We learned our lesson and this system is already in place at my dealer.

I highly recommend you take it to a shop or talk to a certified ASE tech before you proceed. Good Luck!

Aloha,

Pat