jeffls400

I wanted to share my experience on refreshing my a/c system and converting from R12 to R134a on my 220k mile LS400. My decision to DIY was driven by the nearly $700 the local Lexus dealer charged to "repair" my a/c last year, only to give up when they could not get it to work for longer than a day.

I began by replacing the evaporator and expansion valve. It is a labor intensive job, but definitely not out of reach for an average DIY mechanic. From there, I removed the Evaporator Pressure Regulator (sometimes referred to as a suction throttling valve) and disassembled it (six screws). After inspecting the rubber diaphragm for any tears or holes, I reassembled with PAG 46 oil and a new o-ring on the spring-loaded "piston". This o-ring is like a compression ring, so to speak. From there, I removed and sent out any rubber hoses (discharge and suction at compressor and the suction hose sections between the evaporator and the compressor) to be replaced at a local machine shop that repairs a/c hoses. I was very pleased with the quality of the work; the assemblies looked very much OEM, at a savings of over 50% versus the best online prices for new hoses. With the system this far apart, it was very easy to flush the remaining parts (ie the condenser and small miscellaneous lines) with a "flush gun", that can be purchased / rented at most auto parts houses. I then replaced the compressor with a rebuilt unit from a gentleman in Texas, who was a wealth of knowledge and provided a great product. The last new part was a new receiver-dryer. When all of the parts were ready, I reassembled the system with new HNBR (essential for R134a) o-rings, including several seals where two pieces of tubing thread together (the service manual refers to them as Brock joints) and use o-rings to eliminate leakage. After reassembling, I pulled a vacuum on the system with a small vacuum pump for about an hour and a half, to ensure that all condensables were removed from the system. The system held this vacuum for 15 minutes, meaning no leaks. I then added about 28oz-30oz of R134a to the system with a set of manifold guages, to ensure that the high and low side pressures were within spec. The center registers now deliver air at 38 degrees when the ambient temperatures are around 95 degrees.

For those interested, here is a breakdown of the expenses involved:

Parts
Compressor: $200 (1yr warranty)
Rebuilt Hoses: $150
Evaporator: $130
Expansion valve: $36
Receiver-dryer: $15
O-ring kit: $6
Parts Total: $537

Supplies
R134a: $21 (3 12oz cans)
PAG 46 oil: $9 (8oz)
Supplies Total: $30

Tools/Equipment
Manifold Gauge Set: $50 (may be rented/borrowed)
Vacuum pump: $90 (again, rented/borrowed)
Leak checker: $75 (optional, but good for piece of mind)

I happen to own these tools, because I love to work on my own projects.

Let me know if you have any questions.

Jeff

trukn1

Sounds like you saved yourself a good amount of money and have the knowledge/experience to do this type of work. I would stress that this type of work A/C systems, CAN be very dangerous to an untrained person and unless you are qualified, or trained to work on your A/C system it is a job best left to a trained person. There have been many instances of people being hurt and possibly killed while trying to work on their A/C without the proper training/knowledge. Bottom line, if you don't know what you are doing, or even question your abilities, let a qualified person handle the work. To the OP, seems like you got a great value thru some very valuable training/ exposure.

jeffls400

Well said trukn1. I spent summers and holidays working in my grandfather's a/c and refrigeration shop as a teenager. If one does not feel comfortable with the charging aspect, then I would recommend farming this piece out; my system was free of any refrigerant when I started, so for most in a similar position, the mechanical side can be handled at a great savings.

tenchu

Could you let us know where you got the parts (other than the lines which you got locally). I haven't been able to find a compressor for under $400

PureDrifter

iTrader: (10)

www.car-part.com

fencera

Amazon has a new Denso for $318 with free shipping. I just bought one a few days ago.

somnoboy

If any of you guys are going to attempt any of this a/c stuff, I'm sure many here (including myself) would benefit greatly from seeing this in pictures. (Maybe even youtube?)

fencera

As awesome (!!) as this write up is and as many different mechanical and electrical things I have done with this car, one thing I am not touching is the a/c system. Too much specialized equipment for me to justify unfortunately.

That said, when I do take the car to the shop, I am definitely going over the points/steps Jeffsls400 outlined in that first post.

jeffls400

The A/C is working great after two years. However, I am regrettably looking to sell the car, and I hope that having a well-performing A/C will be a good selling point now that the daytime highs are near 100.

Jeff

deanshark

When this thread popped up last month I didn't realize it was a 2 year old thread. But anyway, Jeff, I'm glad it's still working good after 2 yrs, especially with all that work. Gotta have A/C. (I don't) Sorry to hear you're getting rid of the car but yes, having A/C is one of the most important things when buying a car in the summer. If you don't mind me asking, why are you selling? Good luck on the sale.

jeffls400

Thanks - I really hate to part with it, but I bought a new Prius which I use to commute 500 miles per week... The LS just sits at home 5 days a week, and my wife and I just don't need three cars. If I had the time, I would do a complete cosmetic restoration and keep it as long as I could.

jdm2191

iTrader: (1)

I wish they made r12 that wasnt so bad for the atmosphere so us guys with early 90's cars wouldnt be so screwed.