bigguy SC3

Just retrofitted my ac system with r134a and it gets cold but the compressor has a fairly loud whine to it now. If any one has any ideas I'd appreciate them.

VQT

Don't know the answer to the loud whine. But
Did you charge it with R-134a oil first before charging the sys. with R-134a freon?
Did you vacumn the sys. for at least an hours or more?
That what the guy who retrofit my car did.

whitediamond

What oil did you use? Page or Ester?

Did you just drop the R134a into the system that already had the R12 in it? Or did you completely deplete the R12 first?

How much R134A did you use?

Did you adjust the thermostatic temp control a half turn counter closckwise? This really would affect cooling more then make a whine.

---------------------------------------------------

I would not run the system with a whine in it. I have done 2 SC retrofits and they went very smooth and reached around 98% of the temp that the R12 system put out in the center vent which is pretty good for a R134A retrofit.

bigguy SC3

I drained the system of r12 then added r134 with the retro-oil mix that came with the kit. I noticed the whine so I discharged the system again and recharged it again with the same result. I have borrowed a vaccum pump and am going to evacuate the system again!! Should I replace the receiver/dryer?? Does the sc's have a orifice tube??I have a factory manually but some areas are rather vague on troubleshooting. I did use more oil the 2nd time and added approx. 33 oz. of r134.

whitediamond

No orifice tube on this car. I certainly sounds like either an undercharge (not enough freon will not carry the oil through the system), or not enough oil. Since there should of been opil in the system already and with the addition of the retrofit oil, I would assume an undercharge or too much air in the system. A proper evac. sould be in order. A min of 45 min -1 hr is recommended. It is always a good idea to change the Rec/Drier, bit not always required. The SC Rec/Drier model is compatible with R134A.

bigguy SC3

I just talk to a friend and he said you shouldn't add as much r134 as you would r12 because it expands more?? Do you have a ball park figure on gauge pressures with r134 are they the same as with r12??

whitediamond

He is correct. Also, you cannot use the sight glass because of this reason. The biggest issue with R134A retrofits is the charging of the system since all cars have different readings as im sure you know. The best way to charge the system (getting widely adopted), is to charge the system with 1 pound of R134. Then add 2 ounces at a time until the center vent temp is at 30 degrees ambient temp from 5 feet in front of the car. This is actually a new procedure that is being widely adopted and in fact I went through the class 3 days ago on AC temp readings. Now of course if you have a mix problem (heater valve broken) then this will not work, but the SC's do not normally go through this. Also make sure that you are using ester oil and not Pag oil which is very harmful to components.

bigguy SC3

OK, I evacated the system for about 1 hour and it held the vacuum for 1/2 hour, no leaks in the system. Rercharged with R134, didn't not add any more ester oil not much came out when I vented the system. Used about 28oz. the R134. Does get colder but the whine is still there but not as load. According to the manual you should only add .7 oz. of oil when replacing any major component. Do you add more oil to R134?? More oil is the only thing I can think to do.

The Ikon

Go talk to a couple a/c guys and get some tips... Also do you know any one that works in the service dept. at Lexus for some info???

If the whine is not gone soon... It may be time to bite the bullet and take it to a shop you frequent/dealer ship...

Keep us posted...