Air Conditioning Conversion to CFC-Free Refrigerant (R-134a)

Reports on R-134a Conversion Experiences
Questions and Answers
Compressor Replacement
A/C Parts Sources
 

Reports on R-134a Conversion Experiences

Gregg Feldman reports successfully having his A/C system converted to R134a. Its output temperature after the conversion is 40 degrees F. He purchased a receiver/dryer from Atlantic British for 61.92 (including delivery and and sales tax). The local radiator shop charged him $135.10 tax included, to install the receiver/dryer and convert the system, for a grand total cost of $197.02. The upgrade sticker states the system has 1 lb 8 oz. of R134a Freon, and 8 oz. of ester lubricant. James Howard also converted his, 89 model, and reports vent temperatures of 35-40F when ambient is 85F, and 50F when ambient is 107.  Passengers are comfprtable  until ambient temperatures hit 100, when the rear seat occupants start getting uncomfortable if they are on the side in the sun.

Larry Michelon offers the following information on updating your Range Rover's Air Conditioning system to the new CFC-free refrigerants. The main requirements are removing all the old Freon 12 and oil from the system,  replacing the dryer and installing adapters for the charging connectors to make them compatible with the R-134a charging kits. The expansion valve does not normally need to be replaced.

Removing the Freon and R-12 Oil
If you wish to do the job yourself, you should first get the system discharged by a professional shop to remove the Freon. Then, when you get it home, the system needs to be flushed of the old R-12 oil, using one of the following options.

1) Compressed air. Simply blowing compressed air through the hoses will remove a majority of the oil in the system and is considered adequate.

2) Chemical (at home) flush. You can buy this to help further remove the R-12 oil ($12 from Pepboys). Pour or blow it through the hoses, evaporator and condenser. Then blow out with compressed air. This requires the removal of the expansion valve (as recommended by the chemical flush and a "pro" Larry talked to). It is a major inconvenience to get the expansion valve out as you have to disassemble most of the dash (which takes about an hour after repeated practice;the hardest part is trying to get the radio back in afterwards). Larry had to replace his anyhow because his  receiver/dryer gave way sending all sorts of crud into it.

Along with flushing the system, you also need to drain out the R-12 oil in the compressor (there's a little fitting) and refill with R-134a (ester) oil (about 5-6oz)

3) Professional flush. Some shops have a machine that can hook up to the system and flush it without having to remove the expansion valve. The cost is about $175.

4) One air conditioning service man told Larry that some machines can evacuate the freon and oil, including the oil in the compressor. You would just have to make sure they show you how much oil was dragged out. A system will hold about 6oz of oil.

Replacement Of System Components
As far as changes to the system, you really should replace the dryer ($20), adding about 1oz of new R-134a oil into the new one. You also have to install adapters (hi and low side) on the Schrader valves (located on the back of the compressor) that adapt them to the R-134a quick connect hoses and cap off any service port (there is one the dryer on my '89). Larry bought a conversion kit ($20) that has adapters, R-134a oil and assorted O-rings (for any connection you break).

Larry's Experience
Larry Michelon reports that his own conversion did not go exactly as planned. In addition to replacing the dryer ($20) and expansion valve ($23) and one hose ($20, made while he waited, yanking the entire system apart, flushing it out and reassembling with the necessary new parts he headed to the A/C shop to have it evacuated and filled. Unfortunately, the  shop reported that his compressor was shot. So, there was another expense of $200 to have it rebuilt. He also found he had to replace his thermostat switch ($75 -- a common failure item -- see Common Problems and Fixes),  The thermostat switch and expansion valve replacement required disassembly of the dash. Then it was back to the A/C shop. Total cost was $500 to get it working again.  If he had a shop do all the work, it would have cost close to $1000!

Overall Advice
Most people who contemplate switching to R-134a consider it because their current A/C system isn't working. Larry advises that if your system isn't working, find out what all is wrong before you start to pull it apart. Larry tried piece by piece and ended up pretty frustrated and having to replace some things twice. If your system is fully functional, you shouldn't have to do too much to convert other than replace the drier, change out the oil in the compressor, install some fittings, flush/evacuate the system and fill with R-134a. Larry was quoted ~$120, minus the drier, for this. However, it is recommended that you replace all hoses ($10-20 each made at an A/C shop), depending on age and access. At 11 years and 170k miles, Larry found most of the hoses to be "hard" and experienced several leaks at the hose fittings.

Questions and Answers

Larry Michelon has offered to answer questions about air conditioning conversions. However, before contacting him, see if your question is answered below.

Q: "If I replace the receiver dryer and compressor do I still have to flush the system?"

A: This will have removed most of the oil, but you will still have to flush as stated above with at least compressed air.

Q: "The compressor comes filled with PAG oil, do I need any more added to the system?  If so, how much more?"

A: Larry's A/C shop advised adding 1oz of oil into the dryer (because it was being replaced).

Q: "Do I need to change any of my fittings, or can I reuse my existing hoses and fittings?"

A: They should all be fine, but consider replacing any O-ring you can get to easily. R-134a leaks easier.

Q: "Someone posted a web site with a $20 valve thingie that's supposed to improve performance.  Anyone know if it really works? Where does it go?"

A: Sounds too good to be true. If you do a decent flush and replace the dryer, it should work better than you last remember it.

Q: What about alternate brands of Freon?

A: It is best to stick with R134a since you can get replacement cheaply and readily. At the A/C shop, 12oz cans of R-134a are about $3.90. R-12 is now up to $20-30 a can.

Compressor Replacement

Dave Brown found out that his compressor is the "QC" head type. (Land Rovers also use an "MB" head)  This is stamped (raised letters, actually) on the rear end of the compressor (wipe off the grime and use a mirror to read it). This means that the Sanden 4708 (SD7H15) would work for Dave's RR. This is a Sanden "709" style compressor.

Dave found a new compressor that was "liquidation stock" and therefore had no warranty, but it was only $176.  It was new, in a sealed box. It has the "older" style clutch instead of the "three eye" type, but Dave's old style clutch has never quit, and still works after 13 years. The new compressor had PAG oil in it, and a "Freon 134a" sticker on the box. Air Components, the source where Dave found his unit, have a web page, www.aircomponents.com, or their contact page:  www.aircomponents.com/newpage2.htm

Dave also found an AC shop locally that would sell him a new Sanden compressor for about half dealer cost. However they may have needed to re-use the unique Land Rover fittings from the old compressor.

Dave reports there is a Sanden site (see links below) that has TONS of info on their compressors, including oil capacities. Their "retrofit" page says to use 4.6 oz +- .5 oz for systems with expansion valves.  But Dave says not to take his word for it -- check this for yourself to verify!

A/C Parts Sources

AutoPartsGIANT.com has a Conversion Kit (R12 To R134a) complete with Pag Oil or Ester Oil for the Sanden SD709 Compressor for $32, or without the oil for $17. These parts can be easily found on their site by clicking on "air conditioning" and choosing vehicle make "Land Rover" and your model year.
AutoPartsGIANT.com also seems to have the lowest price I have seen for Range Rover Classic A/C compressors (June 2003); they sell a Ready-Aire brand remanufactured complete compressor and clutch assembly is  $298 with free shipping (click on "air conditioning" and choose vehicle make "Land Rover").
AMC in Florida rebuilds the Sanden compressors used in RRs for $175 (plus shipping). They will also fill the compressor with Ester oil so it is R-12 and R-134a compatible.
Atlantic British has new compressors for $500.
Sanden Website has information on compressor models used in Range Rovers.


 

 

 

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Page revised February 1, 2012