I'm finally ready to proceed with that but I ordered ES-12, not industrial one.
Can I still charge it into deep vacuum? There is some confusion there.

If I let system take as mach while not running car and then shut valves, start car and start charging?

 

You'll want a lower pressure with es12a - about 20psi low-side. I know i12a can be charged into a deep vacuum fine, I'm not sure with the es12a but I'd try it anyways. Put maybe 1/2 can in before starting the engine. Charge slowly as liquid.

 

I don't think this applies to the FD, but on some vehicles, if you run a low-pressure of about 20psi, the A/C compressor may cut-out due to a refrigerant low-pressure cut-out switch which is usually triggered around 2-bar (30-psi), at least on a W124 Mercedes.

:-) neil

 

Actually, I cancelled order and ordered industrial one. So, charging 1/2 can liquid and the start and charge another half? I think 1 can should be fine for MANA system?

 

Then low-side should be 30-35psi at 2000RPM. At normal idle it will probably be around 40psi. Mine reached my target pressure after 1 can and I'm pretty sure it's a MANA system. 1/2 can before startup will get some pressure in there to trip the pressure switch and get the compressor to run - it's been a while, but I think the pressure switch triggers at about 1bar/15psi.

Spray the condensor with a hose for a few seconds after getting it to where you want, pressure will drop and then resume adding to get it back up to the correct pressure.

 

+1, I prefer the industrial product for the FD. Since the low side pressure is primarily controlled by an expansion valve, this seems to work better. You can charge most of the 1st can in before you start the motor. Although pressures will look pretty normal after one can, the system will be undercharged. Two whole cans of I12a will get you close. I have found that adding additional refrigerant to clear the sight glass of bubbles at 2000 rpm/AC fan on high/ambient approx. 80deg F. will produce the best results.

If it seems to take a while for the AC to get going (while the car is in motion), then the system is probably undercharged.

 

93 FD Touring with the Nippondenso system. System vacuumed down to 29 inches and recharged with 2 cans of ES 12a - low side pressure is 60-70 psig at 1000 RPM and high side is 300-350 at 1000 RPM. The compressor clutch is cutting out about every 5 minutes - I believe there is a pressure cut-out switch on the compressor itself. I have bypassed the high side pressure switch by the dryer and the AC relay - I am powering the comp clutch directly with B+ - and the comp. still cuts out. Also last night while revving it to 2500 RPM, I believe the pressure relief valve on the compressor opened and vented some refrigerant - yes it scared the Sh$$ out of me...

I think there is a restriction in the system somewhere - I've just done a motor swap and maybe I've kinked or pinched something - I'm going to check the condensor lines first. Any other ideas where to look??? Could the expansion valve be plugged? The system does blow cold air when the comp. is running and there are no bubbles in the sight glass.

Any AC experts out there have any ideas??? I've searched and searched but no luck.

Jim

 

Your low side AND high side pressures are too high. If you put in two whole 6oz cans of ES-12a then you have the equivalent of 36oz of R-12 in the system. The factory spec is, IIRC, 21oz of R-12. MASSIVE overcharge.

Don't bypass the high pressure cutout switch unless you want to blow a hole in your condenser or wreck your compressor.

 

2 cans of Es12a in the FD is fine; I run my FD with slightly more than that. I have observed that slightly higher charges work better in systems with expansion valves. Note that the ES recommended "equivalent" charge is an approximation and will vary somewhat depending on system. In the case of the FD, I recommend charging until the sight glass clears, assuming everything else is correct. It should, however, start to bubble or foam immeadiately when ac is cut off; if it does not, then suspect an overcharge.

What it sounds like to me is that there is a massive amount of air trapped in the system. 2 cans of any refrigeration product should not produce this result.

What was the ambient temperature?

 

I was thinking the same thing...although he said he vacuumed the system down.


Depends on how big the can is.

 

Two 6OZ cans - I can promise you I'm not overcharged. Less than two cans actually - just charged until the bubbles went away. Ambient is about 90-95 F (Texas - yes it is HOT). I've got a box fan blowing on the condensor/radiator - radiator fans are on. Evap fans on high, recirc button pushed - windows open.

This system worked OK before my engine swap - but I plan to check all the high pressure lines in case I've kinked something around the condensor. I can't think of why else the high & low pressures would be so high. The delta P across the compressor is good - and it acts as I would expect - the low side gets lower and the high side gets higher as you increase from idle to 2500 RPM.

The low side pipe from the Evap is not freezing - so per the manual I don't think the Expansion valve is clogged. Also - I pulled a very deep vacuum on the system - I've borrowed a really good old appliance repair man's electric pump - it will pull down to 30 if I leave it long enough - I've even done it twice now. System also seems to hold the vacuum for 15 mins - so I don't think I've got a leak.

I noticed that there's insulation on the high pressure line as it runs cross-car by the radiator - I thought the high pressure lines were usually exposed as much as possible so they can reject heat - at least they are on home AC systems...

Any ideas boys?

Jim

 

Are you using a new receiver/dryer ? Perhaps it is slightly plugged ?

If you're not seeing bubbles in the sight glass at idle, I'd be concerned . . .

:-) neil

 

Nope - same old receiver/dryer - but the system was closed and pressurized during my two year downtime. One thought I've had is maybe the system was converted over to R134 - and I just put HC based refrigerant in the system - even though I've pulled a couple of deep vacuums, I wonder what kind of oil is in the system now? Will HC based gas react badly with the PAG oil if that's what's in the system? I've added no new oil myself. There are no R134 quick connects on the system to suggest anyone has done a conversion.

If I don't see any obvious kinks in the pipes, I'm going to open up the system and blow compressed air thru all the pipes/condensor and see if I can find a blockage.

Since I would then be out of my ES12 bottles, I've been thinking of recharging the system with propane just to test it - anyone ever done this? Don't call the bomb squad on me - isn't ES 12 just a mix of propane and butane?

Jim

 

Supposedly the ES12 is compatible with BOTH mineral and PAG oils. So whatever oil you add, if you even added any, it just has to be the same type that's previously in there.

Since my systems were previously R134a, I have only had PAG, and the ES12 hasn't been a problem for almost a year.

BTW: when you vacuumed the system, you did have both High and Low systems open and the connector ***** screwed almost all the way down correct ?

Also, you only SLOWLY recharged into the LOW system as liqued (high system closed off) ?


:-) neil

 

yes to both of the above:

Vacuumed with both low and high side manifold valves open

Charged only thru the low side with the high side manifold valve closed.

 

Did you charge as a liquid (e.g., can upside down), and slowly ?

Just trying to cover all bases here.

:-) neil

 

the lines to the dryer appear to be crimped - so I tried to uncrimp - vacuumed down again to 29/30 in Hg - recharged with propane. Same result - at 2000 RPM low side is 40 and high side about 240 - but no cool air. Compressor clutch kicks out after 5 minutes, waits 10, then kicks back in - foamy sight glass - but I dare not charge it anymore because I don't want the high side Pressure to go above 250. At idle the low side creeps up to 70 PSI. I have another compressor - I'm going to swap that on and blow air thru the condensor, dryer and high pressure lines to check for restrictions.

Jim

 

i have a spare compressor if u need one.. i also have two 40 pound tanks of real R-12 LoL

 

Is the low pressure line cool or cold where it exits the firewall? It may be cooling just fine and you have a problem with one or more of the control flaps under the dash letting hot air from the heater core into the mix....

 

I can get cold air of it if I charge the high side to about 300PSI - so I know the vent door system is working - the evap is just not getting cold enough.

I found my spare compressor so I 'm going to swap that one on...

 

I think I just wasted a day installing a new (used) compressor.

900 RPM, 60 Low 260 high , sight glass is foamy
2000 RPM 40 Low 325 high, sight glass is foamy

Air is colder at 2000 than 900 - but still not really cold. (90-95 ambient outside , it is probably blowing 50 degree air)

The pressures would say I am over charged, the sight glass says I am undercharged. The old compressor was dry of oil - the new one has better compression - but still seems weak to me. It's doing a better job that the old - but still not good enough. I am using propane but I've been told that's as good or better than R12.

I think it is time for a new compressor and a new dryer.

AC Experts - is time to check/replace the expansion valve also?

Thanks

Jim

 

You're using pure propane and not a propane/isobutane mix? If so, that's why your pressures are too high.

 

+1 This is correct. Pure Propane cannot be used as a direct substitute for R12. It must be mixed with isobutane in order to have the correct pressure/temperature characteristics for a R12 or R134a system.

It is normal for the low side pressure to climb (and evap. temps to warm up) at idle and lower speeds. This is because the FD doesn't overdrive the compressor like most other cars do and this effect is exasperated with underdrive pulleys. In my experience, the FD compressor needs to be turning at least 2000rpm in order see the ultimate low side pressures. Keep in mind that low side pressure does infer the evaporator temperature.

No need to replace the compressor or the drier. Vac it out again. If you hold it in high vac for a while, any moisture in the system, including the dryer will flash out; especially if the ambient is very warm. Put 2 full cans of ES i12 in it and call it a day. (If you find the system is undercharged, you can top it off by adding a small amount of straight propane.)

Pressures will vary depending upon the ambient, but you can expect 35-->40# on the low side and 225-->250ish on the high side IIRC, if it is warm out. Condensing pressures will also vary greatly with airflow over the condensor. If you are drawing through a FMIC, your pressures are going to be high, perhaps very high. On the other hand, they will be on the lower side with a vmount. Stock setup will take the middle ground, depending on the amount of obstruction behind the fans. I assume properly operating stock fans in all cases. High side pressure will also drop once the car is moving due to improved airflow.

Note that if the high side drops too low due to an undercharge, then system capacity will be diminished because there will not be enough of a pressure drop across the expansion valve to move the required amount of refrigerant. Additionally, if gas (as opposed to condensed liquid refrigerant) is present at the expansion valve inlet, the expansion valve capacity will be significantly diminished--again resulting in the reduced cooling capacity for the system. This is why it is necessary to JUST clear the sight glass of bubbles when charging. On the other side, overcharging can increase low side pressures with the direct result of increased evaporator temperatures and loss of performance.

As a general rule of thumb, and assuming adequate compressor RPM, HIGH side pressures are going to be most affected by the ambient temperature and condensor airflow--the latter being very, very important. Similarly, evaporator temperature & performance is going to be determined by the LOW side pressure and an adequate supply/flow of condensed refrigerant at the metering device (there's that condensor airflow factoring in again). Air discharge temps will vary widely with conditions, but will typically be in the 50-->60 deg. F. range. 50's is good performance once a system has stabilized, anything in the 40's is great performance.

Hope this helps.

 

thanks - will vac again and wait for my new case of ES12 to show up... I have been misled in the past that pure propane would be OK - I suppose not... I actually have one 12 oz can of R12 left from 15 years ago - but it is the old flat top puncture can and I don't have a tap that will work for it...

Condensor/Radiator set up is stock - with a Koyo Rad - I've been running with a box fan flowing at the nose of the car - obviosly not like driving but there is some airflow.

Any Ideas on where to find a compatible mineral oil for ES12/R-12?? I will check the ES12 website...

Thanks for the help

Jim

 

Or....

Brew my own propane/isobutane mix at home? Does anyone know if these cans screw onto a R134A charging hose???

Each can is 4 oz total with an 80% Butane/20% propane mix, so three cans would give 12 oz total - 80/20 mix - is this too rich in Butane or would it work as well as ES12???

Jim

Link:

http://cgi.ebay.com/MSR-Isobutane-Ca...2em118Q2el1247