I couldn't find the sticker on my truck and I'm converting to R134. 1990 regular cab W250. I've pulled the compressor and dumped (what little ) oil was left in the system. I saw one post that mentioned 8 ounces, of oil and about 30 ounces of R134a. Anybody out there want to confirm or deny that for me?

Thanks!

 

FSM says 44 oz max. What I do is start with an oil charge can of regrigerant, then start charging while watching the sight glass. Stop when there are only a few bubbles, let the system stabilize then slowly add more until the sight glass clears...Mark

 

Does it say how many ounces of oil its supposed to have?

 

It doesn't, but usually a can of oil charge has enough oil for the system. Most domestic non-commercial systems use only 2.5 to 3 16 oz cans. I would think that 1 oil charge would be enough, but I would read the instructions...Mark

 

From what I have read, whatever amount of R12 is required you only use 80% of 134. I set mine per the system pressure, 90*day,265psi on high side, 36psi on low side. About 44* duct temp.

 

That is the best way, but the pressures will vary with atmospheric conditions, there is a chart in the FSM...Mark

 

Yeah, I was aware of the 80% rule but thanks for posting it for other people who read this.

 

clear sight glass with 134 is too much refrigerant

 

I finally found my sticker, it was a little hidden. It says 44oz for gas engine but 41oz max for diesels.

I put around 7 oz of oil in the compressor (started with 8 but spilled some and couldn't get all of it dumped in there), then charged with not quite 3 - 12 oz cans of freon and it seams to be working just peachy.

I'm glad to see that comment about the sight gauge. Mine always shows a haze of freon/oil going by. I was expecting it to clear up but it never did.

 

I'm working on that same problem now ,i think "jug" may be right about the bubbles, at least mine has never cleared up , or gotten cold .......yet.

 

the way i charge with 134 is strap a digital thermometer to the evaporator and charge till it reads its coldest. then i add slowly until the temp starts rising. then discharge until the temp goes back to the coldest reading i got. so far it seems fool proof.