Packard Forum Index » V-8 (1955-56)

55 and 56 but only the latter was negative ground.

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Hello,

The 1955-56 Packard factory air conditioning system was very efficient and in some ways it was over-engineered. It was one of the industry's MOST advanced A/C systems. 1955-56 Packard A/C was wayyyy ahead of most of the industry with its theater style front-mounted units flowing rearward rather than rear-to front. Or top-down arrangements that could freeze bald heads while the rest of the customer was sweating.

You may want to note that 1955 and 1956 systems differed slightly, particularly in the hoses. The 1955 hoses had a braided covering while the 1956 hoses had no such covering.

But whether you plan on using freon R-12 or newer R-134 refrigerant, I still strongly suggest that you do R-134 grade hoses. The cost of R-12 alone (ask me how I know) and the hassle of finding it (actually illegal in some places) would all offset the cost of R-134-grade hoses.

RE: the original Lehigh V-4 compressor... These look lovely and are certainly original. But finding a working one and /or parts to repair one? OMG! There are a few out there still working today, but how long could Noah tread water? I have suggested that (like some people are doing with car batteries on vintage cars) 3-D modeling on a case facade that could be mounted over a Sanden compressor for display purposes is a possibility. Otherwise it is a matter of how deep are your pockets? How extensive are your parts resources?

IF you want your A/C system to actually work, then you may be looking at a reality of a modern Sanden cycling compressor. Even if temporary. And believe me, I am not at all a fan of modifications on Packards. And I don't put this in the category of "disc brakes" or nitrous.

Meanwhile... things always change, so hang onto your Lehigh compressor. Somebody MAY eventually have another re-build business.

Cohocom, for including your '56 Executive Hardtop Coupe in the Registry.

I'm in the process of adding a factory A/C system to my '56 Caribbean Hardtop. Have an original NOS Lehigh compressor and NOS clutch. Decided to go R134 as R12 is enormously expensive here in Southern California. What my A/C guy recommended is going with a cycling clutch as the original modulating would not work with the R134. We then gutted the modulating valve, so it just functions as a "pass" through, then added a module to cycle the clutch ala modern cars. Also, as mentioned in other posts, the original hoses, which I bought a few decades ago NOS, are not compatible with the R134. According to my A/C guy, the rest of the system should work fine with the R134. We will see in a few months how successful we are. Have heard stories that at idle or low RPM the Lehigh is not efficient and will not blow cold as modern systems. Any feedback on that issue? Thanks.

If you do use the Lehigh compressor, the original oil used with Freon R12 is said to be not compatible with R134a. Not sure of the extent of incompatibility but several professional AC sites say It is highly recommended the old compressor oil be drained and all components flushed a couple of times to rid the system of any traces of incompatible oil before new R134a safe oil is placed in the compressor and system. Several sites also recommend new filter/driers along with the new oil.

In the owners manual it says that if you want the AC to blow cold at idle, you need to feather the gas a bit to raise the idle. It’s just how they were.

All the compatibility points are valid. Do not expect a system designed and sized for R12 to blow as cold with R134. Before its environmental downside was known, there were reasons R12 was the choice

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Please. Air conditioning systems always cool less at idle and low speeds– especially in high ambient temperatures. "feathering the gas" merely serves to turn the fan faster... which in turn sucks more air across the condenser core... with the expected result. But this is not "just how they were" as if Packard V8s were somehow less or special primitive cases.

This is a universal procedure for ANY automobile with air conditioning. Right up to today. I can do the exact same procedure on my modern Lincoln and marginally boost A/C cooling. The only difference is that today most cars with advanced A/C systems equipped with R-134 also have a "recirc" setting that can help lower the air temp in the cabin (most people today have no idea how "recirc" works or even that it exists).

A cycling clutch on a Lehigh compressor is, of course, a good idea in today's world.

But remember, R-134 is less effective for cooling at idle, in heavy traffic and low speeds in hot weather. It can actually have worse cooling than an R-12 system. So let's not make the A/C system on V8 Packards sound lame. As I have said, it was one of the most advanced, best functioning factory air units in the industry at the time.

IF someone has a Lehigh compressor that is indeed functioning properly AND that person can obtain R-12, then by all means, the investment in R-12 is ginormous (and in some cases, illegal). But the investment is certainly worthwhile in light of the costs and technical issues of an entire changeover and related angsting. Lesser of two evils is still lesser– IF you want a functioning system. Old luxury cars are expensive... and the older they get and more complicated they are, the more expensive they get.

Compressor speed is low at idle, and engine fan speed is also low. Both of these conditions reduce A/C performance, and road draft is also lost. An auxiliary electric fan might be helpful in traffic, if it could move a LOT of air. At idle and low speeds on sunny days, the exterior of the car can get very hot, which further challenges the A/C. Setting the engine idle a little higher than normal will help cool things off at idle if you have a manual transmission. With an automatic, I'd stick with the factory spec on idle speed. Keeping everything as clean as is practical helps heat escape. Radiator, evaporator, and condenser need to be kept free of bugs, grass seed, dust, etc. and keeping the engine and transmission clean helps cooling. Keeping door and window seals in good condition will help, and any floor, firewall, roof, or or other insulation needs to be in place and in good condition.