1966 Mustang A/C not cooling very well

[IHaveAMustang]

I had installed/repaired an A/C system last year. Sanden compressor (R134) and new Condenser/Dryer/hoses. Sometime this winter it leaked all out. The only thing I have never touched is the original R12 Coil system in the actual interior unit.

Replaced it this weekend with my dad's help (never touched the inside of one before) and pulled a vacuum and put three cans of R134 in, plus 1 can of oil.

The coil reads around 50 degrees with a laser temperature unit, but it just doesn't seem cold coming out. I put 2/3 of another can in the system and it helped a little bit. Right after charing the system I was seeing 44* but it warmed back up to 50.

I see slack in my compressor belt and will try tightening that up tonight.

Thoughts? Pretty much a brand new system at this point.

[Z06killinsbf]

Clogged orifice tube will do that

[Baron Von Crowder]

Clogged orifice tube will do that

expansion valve system.

[2011GT]

Why did you add more oil? My guess is you have too much oil now. Some freon even has oil already in it. Are you using a dual gauge ac servicing gauge set? What are your pressures? What's the temp coming out of the vents while driving?

[IHaveAMustang]

Why did you add more oil? My guess is you have too much oil now. Some freon even has oil already in it. Are you using a dual gauge ac servicing gauge set? What are your pressures? What's the temp coming out of the vents while driving?

We added more oil because I ran the compressor a few times without Freon in it (testing it) and figured I had probably used some oil up. I only ran it for 30 seconds or so at a time. Compressor works fine.

Yes, the blue/red gauge set. I need to check my pressures this weekend and will post back.

Temp while driving is roughly 50 degrees at the vents.

If I added too much oil, why was it blowing in the 40's for a while? Did the oil have to work it's way through and ruin the system?

[IHaveAMustang]

Clogged orifice tube will do that

I don't think this system has an orifice tube or expansion valve. Very simple system, modeled after the 1966 system (just no R12)

Condenser, Dryer, Compressor, Internal A/C unit with Coils. That's it.

[shumpertdavid]

It's an expansion valve type system, it has to have something to create the pressure differential (orifice tube, expansion valve, expansion block, etc) Oil generally stays in the system, it can be lost during the vacuum and recovery process and in the case of a large leak. Usually with small leaks over a long period of time, oil loss is minimal. I would start by filling the system with the factory charge amount. If the expansion valve hasn't been replaced, I'd replace it as well. The older r12 version isn't going to be as efficient as the newer r134a compatible one will be. Lastly, just because you've replaced all or most of the components in the last year, it doesn't mean that one of those can't be leaking.

[lilvega]

What oil did you put in it?
R12 oil and 134 oil are not compatable together. Any system I have seen converted that wasn't properly flushed out or completely replaced had poor cooling.
If you re-used the stock coil under the dash then it had R12 oil in it and probably contaminated the comperssor, dryer and condenser. I would flush it really well and try again.

[IHaveAMustang]

What oil did you put in it?
R12 oil and 134 oil are not compatable together. Any system I have seen converted that wasn't properly flushed out or completely replaced had poor cooling.
If you re-used the stock coil under the dash then it had R12 oil in it and probably contaminated the comperssor, dryer and condenser. I would flush it really well and try again.

I put a new coil under the dash from Old Air Products. This is a 134 system.

There hasn't been R12 in this car probably since it was parked in 1997. I didn't even get the original compressor when I bought it, and I threw away the original condenser. So I highly down it has R12 oil still in it somewhere.

Probably too much oil. I thought it would leak out/be sucked out when I pulled the vacuum, but alas I may have been wrong. Anyone know what the expansion valve looks like on a 1966 Mustang A/C system? What should I use to flush the system? I've never done it before, only pulled a vacuum and charge.

Oh and before any more comments come in, thank you all for helping me with this. Very solid advice and helpful answers.


Edit: Would the system be leaking if it could hold a vacuum of -30 for 30 minutes?

[Whiteboy]

I put a new coil under the dash from Old Air Products. This is a 134 system.

There hasn't been R12 in this car probably since it was parked in 1997. I didn't even get the original compressor when I bought it, and I threw away the original condenser. So I highly down it has R12 oil still in it somewhere.

Probably too much oil. I thought it would leak out/be sucked out when I pulled the vacuum, but alas I may have been wrong. Anyone know what the expansion valve looks like on a 1966 Mustang A/C system? What should I use to flush the system? I've never done it before, only pulled a vacuum and charge.

Oh and before any more comments come in, thank you all for helping me with this. Very solid advice and helpful answers.


Edit: Would the system be leaking if it could hold a vacuum of -30 for 30 minutes?

call old air those guys are good with tech help

[blackedv]

just because it holds vacuum doesnt mean it will hold pressure just fyi

[lilvega]

I at least let it sit overnight and make sure it has the same vacuum reading in the morning.

Sorry I thought after reading your orig post that you ran it with the old coil for a while and just recently replaced it.

[lilvega]

I had installed/repaired an A/C system last year. Sanden compressor (R134) and new Condenser/Dryer/hoses. Sometime this winter it leaked all out. The only thing I have never touched is the original R12 Coil system in the actual interior unit.

Replaced it this weekend with my dad's help (never touched the inside of one before).

Ok, I read it again and I'm confused. You didn't change the coil originally but you did charge it. That means any R12 oil in the coil will contaminate the 134 oil and the other components. The oil will never leave the system without being properly flushed or having 100% of the components replaced. (Hoses too) you may have too much oil too. The coil should be very close 40 degrees.

[IHaveAMustang]

Ok, I read it again and I'm confused. You didn't change the coil originally but you did charge it. That means any R12 oil in the coil will contaminate the 134 oil and the other components. The oil will never leave the system without being properly flushed or having 100% of the components replaced. (Hoses too) you may have too much oil too. The coil should be very close 40 degrees.

I am very good at confusing people, mainly because I don't know what I am talking about...sorry

But you summed it up well. Ran R134 in the original R12 coil after it sat for about 10 years. I (incorrectly) assumed the oil would dry up after being exposed to normal air for that long. I just replaced the coil this weekend with a R134 coil brand new from Old Air, but I imagine it's all messed up and I need to take it to an A/C place for a flush/leak test/ charge.

Or since it's already mid-July, I may just enjoy 50 degree A/C for the rest of the summer and deal with it next year. 50 degrees is leaps and bounds better than windows down on a 100 degree day.

Thanks guys!

[shumpertdavid]

A 50 degree drop from ambient to vent temps is well within an acceptable range. While it's not the best to have mineral oil (what r12 used) and ester or pag oil mixed, the system will usually work. There were \ are plenty of conversions running around that with have or had mixed oils. The oil charge will affect cooling abilities when there is an over abundance of oil, also the original a\c hoses weren't compatible with r134a. They will work with it, but will allow the refrigerant to slowly seep through the pores of the rubber. If you're still running any of the factory lines or if you are uncertain, have new hoses made.