[TxGoats]

I went to a car show last night in Waco Texas and by the time I got there I was soaking wet, it is time to get the A/c fixed in my '67. This car has factory a/c with the factory compressor still in the car. I need suggestions as to which way to go to get the best cooling effect in the car, do I rebuild the old compressor, buy a rebuilt one or a new one. I want to upgrade to the 134a , can this be done with the old compressor? Anyone know of a great A/c guy in South Texas, around Houston?
I need some relief from this heat!
Thanks,
Mike

[Andre]

I suffered from the same maladies that you are when I had my '69 GTO. We converted to R134A for about $200. That was in 2001.

The shortcomings with my car were- not enough floor/firewall insulation, and poor sealing of the ductwork under the dash. As a result, my a/c had to work very hard to keep up on a hot day.

It is not as good as the modern day systems, but it seems to be as good as you could get for the old style system.

[Cammer-6]

134a really needs a condenser larger or more efficient than the R12 ones.
If youre going to open the system up to replace the dryer and seals(really mandatory)
then put a new flat tube condenser in.OH and add a POA and expansion valve calibrated
for 134a.

[wheelspin]

Converting your factory system to 134 is NOT an upgrade. Restore your existing system w/ new hoses, O rings, crimped hose collars, dryer, re-manned compressor, R12, and enjoy the sub 40 degree outlet temps, as it was designed. Don't be put off by the high price of R12 as a leak is very unlikely, after replacing all of the hoses and O rings.

Les

[quicksilver97ta]

Another vote for keeping it R12. Fortunately my Lemans is very original and the A/C is in good shape, blows very cold air. The only draw back is the original compressor is a pig compared to the newer 134 types. But thats OK its original and works great.

[engineer]

R12 is the only way, rebuild yours if numbers matching, otherwise get a new AC-delco assuming yours leaks. AC help, join the Gulf Coast GTOs chapter in Houston and use their technical experts to help you.

[JohnS66GTO]

Considering you're in Texas, sticking with R12 may be a good idea just to get a little extra cooling. But here in Michigan where it still gets into the 90's and humid regularly during the summer, my R134a converted system (stock system with reman Delco compressor & POA recalibrated for 134a) works great. I've measured 39 degrees F at the center dash vent when ambient temperature is in the high 80's. I think that's pretty good for a system not specifically designed for it. I got the same temperature from the A/C in my minivan a few years ago, measured on the same day.

John

[engineer]

don't know about your thermometer, but 39 degrees with 80 deg inlet air to condenser is hard to believe. Actually, not possible with proper charge of 134A and correct pressures accordingly to the PT chart. 80 deg. inlet air does mean the condenser sees that temperature or more. has nothing to do with inside recirc air. it is not a evaporator issue, but ambient air exchange.

[TxGoats]

I talked to the garage that is doing the a/c work on my car and he wants to go with R134a so I am going to try it. I had the compressor rebuilt and while I am doing all this I am having the 4 core radiator recored and adding a transmission cooler. When I ask him about the R12 or R1234a he ask me if the a/c I was using at the time worked well, I said yes it does he said well its 134a, what do you want to do? I found out the old radiator had 6 lines plugged up.
Thanks for you guys input, I will let you know how it turns out.
Mike

[JohnS66GTO]

Engineer:

I agree the temperature doesn't sound right, and my thermometer isn't exactly a high-dollar "calibrated" one. That's why I tried it in my modern car the same day. Got the same result. So 39 degrees may not be accurate, but on that day, which I know was humid and in the high 80's, my GTO was blowing the same temperature air as my modern car (which I've driven across the New Mexico desert in the middle of a summer day and been plenty comfortable).

I guess my point is, a properly operating R134a system is capable of cooling our cars, at least for those of us not living in the 100's on a regular basis. You'll notice I mentioned if I was in Texas I would probably stick with R12 because every degree helps in that heat.

John

[Cammer-6]

Originally Posted by engineer

don't know about your thermometer, but 39 degrees with 80 deg inlet air to condenser is hard to believe. Actually, not possible with proper charge of 134A and correct pressures accordingly to the PT chart.

Because its 80 degress outside doesnt mean the inlet temp is 80*.
If you keep it on recirc inside temp will go down and hence outlet temp down too.
A real test is open doors and blower on high.
I too seriously doubt a retrofitted system will pull 39*.

[Alvin]

Originally Posted by TxGoats

I went to a car show last night in Waco Texas and by the time I got there I was soaking wet, it is time to get the A/c fixed in my '67. This car has factory a/c with the factory compressor still in the car. I need suggestions as to which way to go to get the best cooling effect in the car, do I rebuild the old compressor, buy a rebuilt one or a new one. I want to upgrade to the 134a , can this be done with the old compressor? Anyone know of a great A/c guy in South Texas, around Houston?
I need some relief from this heat!
Thanks,
Mike

Hey Mike - Thank You for asking the same question that we need answered for our 400 4sp with factory A/C ‘67 GTO.

One of our local South Texas "experts" has recommended using a "Super Cool R-12" that doesn't require a license to use and swears that this works and cools "better" than 134. Needless to say I am skeptical with a capital S!

IMO and WADR (With All Due Respect): "Don't be put off by the high price of R12 as a leak is very unlikely, after replacing all of the hoses and O rings." Has never been true for any GM A/C cars we have owned here in Texas (or elsewhere). The compressor clutch seal has always leaked on every one of them. This required 1 to 2 cans each season to recharge to the correct pressures and Freon level. No big deal when R-12 was $0.29 per can...but now that it's $45.00 or more each it can be quite costly. I still use R-12 in ours have had license since they were 1st required to purchase R-12.

Let us know how it works out for you. Most of the systems that I see are Vintage change outs, which although aren't "correct" OEM style they sure seem to keep you COOL in the heat and humidity here!

Thanks again for the post. Let us know what works out for you.

[Cammer-6]

Ive never seen a"blend" r-12 replacement that can be topped off.
This is the problem with a system thats not 100%.
On the compressor seal,I had an old timer(he was then I am now) show me fibers
from the felt washer that get stuck in the seal.
He put a new seal in and got rid of the felt washer and I never had to put any in it again.

[TxGoats]

Well it is blowing cold now, but I found another problem, well really 2 problems. The duct system needs to be resealed, it is leaking in several places and the new blower will only blow on hi. So it is blowing fine it is just blowing alot behind the dash instead of only out of the vents. I am going to seal it all up tomorrow. My other problem is when it is 102 outside the car runs too warm, up to 230 degrees at a stop light, around 215 while driving. We started adjusting the timing and the temps were coming down, but we ran out of time Friday evening, we are going to start again on it tomorrow.
Have any of you ever added an electric fan in conjunction with the regular fan on the car? Or should I go ahead and bite the bullet and order the Aluminum radiator with the 2 fans that it comes with? I have a 4 row radiator and it was just recored.
Also will a new resistor fix the blower only blowing on high? I have one coming.
I want to thank you all for helping me with this, your advise has been outstanding.
Thanks,
Mike

[quicksilver97ta]

I'm glad your happy with it Mike, this heat is brutal. Unfortunately my lemans only has the idiot light but it's never shown any sign of running too hot. It has the original low compression 350. What CID and compression are you running?

Keep us posted on your engine temps.

[TxGoats]

I also have the original 400 cid in the car. Temps have been better since setting the timing, normally running about 205-210 on a 96 degree day. A/C is working well, not as good as my '06 GMC truck but better that the 4-70 a/c I had!

[Tex66Pontiac]

For whats its worth, my compressor went out a few years ago and I still havent gotten around to having it rebuilt. The 100-105 degree heat WITH humidity is a huge pain in the butt. The worst is getting all that heat from the engine and then noticing the back of your shirt is completely drenched in sweat. But it saves me 1-2 miles a gallon
For anyone else that lives in Texas who might come across some AC issues I would highly recommend Old Air Products here in Fort Worth. They've also got a really good online catalog for anyone interested.