Targamike

I picked up a $35 kit that is supposed to convert an R-12 system to R-134a. I know there is no R-12 remaining in the system. I've read that doing a conversion can cost hundreds of dollars. Has anyone had any experience with one of these do-it-yourself kits? It just includes 3 bottles of refrigerant/oil as well as adaptors and a hose.

DaveK

Hi,
It sounds more like a kit to just fill with R134a. I had mine converted and it was about £150 for the conversion + the cost of the refill. Some parts of the a/c system actually have to change and it doesn't sound like you have the bits for that.

Dave
90 C4

Adrian

Dear Mike,
You need to change your receiver dryer. I am led to believe that a 1988-91 Honda one fits perfectly and is much cheaper. If you leave the old receiver dryer installed it will contaminate the R143a with old refidgerant oil and any other crud which is held or built up in the dryer.
You should change these things every few years anyway,
Ciao,
Adrian
911C4

964Cab

Adrian: Just change the A/C drier and thats it ? Would I have to also change all those "O" rings at the various pipe fittings ?

Thanks
1990 C4 Cab with non-working A/C system.

CmackG

I was under the immpression that the hoses needed to be replaced, since the old lines are more porous to the smaller molecule, higher pressure r-134a.
True or false?

Adrian

If the hoses are intact they do not need to be replaced. They have never needed to be replaced but on 964 they tend to leak a bit after a few years.
The o-rings on the receiver dryer need to be replaced (matter of course anyway) but I am not aware of any others that need replacing. Please ensure once you have removed all the old R12 and oil by sucking it all out, then replace the receiver dryer that you run it down again with a vacuum and leak for 15 minutes to check for leaks. Do this before installing or charging the system with R-134a. Applies to R12 charged systems as well,
Ciao,
Adrian
911C4

craig001

You need to think about pulling your compressor and having the oil drained and replaced with R134 oil. The R12 oil is mineral based while the R134 is an Ester base. While I can't give you a scientific explanation, from my research I have the imapression that the two oils are not compatable. The EPA would probably really like you to go to a shop and have the system evacuated before opening the lines. You might want to check out Griffths (sp?) site.

porsche964

I recently bought this same kit, so I am glad to see this post. I am considering returning it, however.

Environmental issues aside, I understand from a mechanic friend of mine that installation of R-134a in lieu of R-12 is an absolute downgrade. I have read other posts by Adrian which talk about how the 964 a/c system may be mediocre anyway.

Would not the R-134a render our already poor performing a/c systems nearly useless? Or, have my fellow 964-ers found it not to be a problem?

Targamike

For better or worse, I am going to try the kit today. I'll keep you all informed of the results.

Doug Leavitt

Below is the factory procedure for retro fitting a 964 to R134A. I have also included the chart of parts and quanities needed (for MY 89 - 92). Note that the quanity changes for the amount of R134A required vs R12.


Procedures

Retrofitting of air conditioning systems to refrigerant R134a:

Important :When working on air conditioning systems, observe safety precautions for operations on the air conditioning system and for handling the refrigerant (also refer to Repair Manual, Group 87).

1. Before starting retrofitting, check operation of air conditioning to see if additional repair operations are required on the air conditioning system (e.g. faulty piping, inoperative compressor and/or system leaks).

2. Connect recycling service equipment for refrigerant R12. Extract and dispose of refrigerant and refrigerant oil properly in accordance with instructions. Measure and make note of the refrigerant oil volume that has been drawn off.

3. Refill the system with the entire R12 refrigerant volume drawn off without the refrigerant oil.

4. Start engine. Switch on A/C system and run engine at approximately 2,000 rpm for approximately 10 minutes. Operate the A/C system to mix any remaining refrigerant oil with the refrigerant so that it can be drawn off.

5. Draw off refrigerant and refrigerant oil. Measure refrigerant oil volume and add to volume determined under item 2. At least 50% of the specified refrigerant oil quantity (see system specifications in brackets) should be removed from the system.

If insufficient refrigerant oil was drawn off or drained, proceed as follows according to the compressor type:

a) Compressor with drain plug:
Remove drain plug to drain refrigerant oil.

b) Compressor without drain plug:
Remove compressor and drain refrigerant oil at port connections.

c) Refit compressor.


6. Carry out any repairs that might be required on the air conditioning system (see item 1). Replace the receiver dryer (see chart) and install without any delay after removing the plugs. Replace O-rings and coat them with fresh ND-Oil 8 refrigerant oil.

7. To allow the R134a service equipment to be connected, fit the required adapters (angle valves or straight adapters, depending on space constraints) to the previously used connections.


New charge:

8. Evacuate system with A/C in maximum position. If system evacuation is successful, proceed with item 9. If not o.k, proceed with troubleshooting (leak) and repair.

9. Fill in fresh ND-Oil 8 refrigerant oil (for volume see charts) using service unit or external filling unit.

Note nly use new oil, used refrigerant oil extracted from an A/C unit must not be re-used.

10. Evacuate system again for approximately 1 hour. Run leak test in vacuum section (the vacuum generated must be maintained for approximately 2 minutes).

11. Fill with specified quantity of refrigerant R134a.

12. Run engine. Check for output and leaks at an increased high pressure of approximately 18 bar. To reach this high pressure, switch off the fans briefly by disconnecting the wiring plug.

scotsman60

The A/C on my '90 C2 just stopped working last week. It's 18 months since I had it leak checked and refilled and I'm thinking aboiut converting to R134 this time.

Does anyone have the part number of the Honda receiver/drier that Adrian suggested should fit the 964?

Adrian

I am trying to find the actual part number. I was informed that from a 1988-1991 model Honda. I recommend you contact your nearest Honda dealer. I would assume that all Hondas of this year range used the same receiver dryer. However I caveat this. Please check your existing one. There are 2 possibilities. A receiver dryer which has the hoses enter directly opposite each other and another where the hoses enter at 90 degrees to each other. You must inspect what you have. The Porsche version available now will be with hoses entering opposite to each other. If I remember correctly,
Ciao,
Adrian
911C4

PS: If you are wondering how this can happen. Porsche stopped sourcing 964 parts a long time ago. You will get 993 or 996 replacements nowadays for a lot of items, especially in the aircon system. You have to take care. This includes the standard hardware components as well. Another important note is that many 964 parts are now past their used by date.

Adrian

Guys the part number of the receiver dryer is actually a generic part number not a Honda part number. This part number ACH 33278 fits the 964s fitted with 90 degree input and output lines,
Ciao,
Adrian
911C4

PS: All this data is courtesy of Nagib Gulam.

CmackG

SO Targamike, how did the conversion work out? 7/9 you said you'd give it a try, how did it go?
If it worked, where did the kit come from?
C

Targamike

OK- I did try the conversion using the $35 kit. I'll spare you the messy (literally) details and just say that if you want AC that works, don't waste the time and money. Take it to an expert and let them do it. I think that the system "flush" is needed to clean the system from old residue.