Which dryer style do you have- the one with the bracket welded to the body of the dryer or the one with the smooth bottle and a clamp to secure it to the car?

 

Seems both styles are available at Orielly's. One style in stock, the other available from the warehouse.

 

I have the one that mounts to the firewall, not the one that you'd see up front. I believe the bracket is welded to it "I think".

 

Subscribed cause its hot dammit !!

 

The AC in my 91 FC that I purchased 7 months ago would blow sort of cold when I first purchased it but in the past month I am getting nothing but hot air. It definitely works though so my first step is to recharge with one can of R152a, correct ? Being a fairly new owner should I be worried that the previous owner could have used R134a to recharge it previously ?

 

It sounds like you have a slow leak. most likely locations are the two service ports high side and low side.

You should address that leak first. Then the first step is to read here: https://www.rx7club.com/2nd-generati...gerant-964688/

 

Will do, thx.

 

93 FD calls for 22 oz of R12. 56% of that for R152, so about 12-13 oz is correct.

Good Luck!

 

I was just looking at the MSDS of Freeze 12 and it is a mixture of r-134 and r-142 (r-134, not r-134a).

I thought r-134 wasn't a good refrigerant, or is Johnsens freeze 12 junk?

 

R134a is a fine refrigerant but our RX7's don't have enough condensing capacity for it to work well.

Freeze12 is a good product for what it is. The original problem converting R12 to R134a is that the mineral oil is not miscible in 134a . That can caused the mineral oil to collect in the drier instead of circulating in the system.

Freeze12 adds the R142 because it will carry the mineral oil around the system. It also has a lower operating pressure than R134a

This doesn't change the problem with our RX7's mainly being that we do not have enough condenser for 134a.

Freeze12 works ok, better than straight R134a, not as good as R152a.

Backup camera is working, USB plug to replace the cig lighter arrives via amazon tomorrow. I really appreciate your help, Jjwalker!

 

GREAT READ~! thanks for the vid, i was shown this refridge school but could not find it. love telling ppl about that vid Y not to use propane type gas.
funny my danfoss PT chart app has 152a listed, il have to order me some new tools this week

 

Wow that is a lot to read. Jackhild59 you really know your stuff! I didn't know the stuff used to clean my computer was a refrigerant (152a). I'm going to try this on my 1990 R12 system. Disconnecting all AC lines. spraying brake cleaner through them and blowing lines out with 80psi compressed air. Replacing all O-rings. New AC condenser, AC compressor and new drier. Mike

 

Ok All torn apart and blown out. Need some clarification. I hear the 134a system works with higher pressures than the R12 system. Does this mean that the 134a compressor compresses the refrigerant to a higher psi than the R12 compressor can? I have a few other questions also. I just want to be sure I'm going to do this correctly. I'm not an AC man by no means. Mike

 

No problem jack, thanks for the AC charge!

 

We had a "pro R134a conversion" done several years ago and the A/C has worked fine all that time until late last year. So I was going to try the R152 but have been stumped by what I think was an incomplete conversion.

The low side has a clean fitting but my HF R134a gauge coupler doesnt seem to fit.




High side?





Low side


Any suggestions for next steps? If my understanding is correct the a/c is a bit more frankenstein that expected.

Thanks!

Jim

 

Nevermind. I was being a Honduh owner. The spring clamp for the BAC water feed was preventing the coupling from attaching. And I see I need to go pick up an adapter for the high side.

If I'm reading the low side gauge correctly, it current has almost 6 bar static on the low side.




btw, anyone else find that the URL option for pictures doesnt work? As soon as I start typing (Chrome) the "t" in "http..." it clears the field.

Thx,
Jim

 

that's about where my pressure reading on my fd is at when off 85psi ish I just did r134a conversion on mine ( from having nothing for years)

did u start with the basics? when u turn the AC on does the compressor clutch engage?
if not u could try jumpering the compressor wire temporarily and force it to kick on ( if you know the system has pressure)

if it works then, take a look ad the pressure switch see if it ohms out correctly
there will also be a thermos swtich for it to shut off in the evaporator as well

resistance values should be in the FSM

 

The compressor comes on. When driving and turning on the a/c the additional load on the engine is obvious.

I'm going to put the R152 in with a new drier and see where we are on the gauges. The drier doesnt arrive until Monday. Orreily's doesn't stock them locally anymore so it has to be shipped in from Georgia. And I couldn't find any on Amazon (yay Prime!), Advanced, Autozone or RockAuto that had the welded on bracket.

 

Jack, I do have a question for you.

I have reread the beginning of the thread about 10 times now and this is what causes me to have this question.

"152a is not miscible with mineral oil"

Since we didnt dump out the compressor, and I believe we put 3oz of ester in the drier assembly, am I still getting good compressor lucrication?

I still blows nice and cold even in the 105+ weather we have been having but now I am concerned about lubrication of the compressor.

 

VR make sure you pull a good vacuum on the system for an hour at least before u go to recharge

 

Thanks, it's been sitting at 30 for a couple of hours now with the pump off. I think it's good

 

shouldn't the new compressor be drained of factory oil? measured then refilled with the same amount of ester oil instead of the factory oil? I drained about 3oz out of the new compressor and replaced with 3 oz of ester oil. my system holds about 6 oz of oil so I'm guessing that I need to add 3 more oz's of ester to the dryer and I'll have correct amount of oil. RIGHT? Mike

 

Whelp, found my leak:


Looks like I can get a gasket kit for the compressor - I just need to verify that it's a Nippondenso. It should be, since it's factory AC.

Works pretty good with E152, until it all leaks out...

 

Nice and cold!

We took out some, probably about half, of the oil you had currently in the system with the drier. It was most likely mineral oil. We added in 3, maybe 4 oz of ester. The ester will carry through the system and you will be fine lubrication wise.

I did it this same way on my 10th Anny back in June and it works just fine for now.

When I do my new parallel-flow condenser on the 10th Anny I will put another new drier on and do a full flush on the compressor. At that point I will have a completely empty condenser, drier and compressor. I will add the exact 6 oz of ester to the system at that time.

 

Best practice, yes.