Packard Forum Index » Modification Discussion

I'm not sure the hose shanks are a good idea either. Use steel tubing w/double inverted flare all the way like original and as so many other cars do from the factory.

I've used rubber hose with barbed fittings on all my coolers and never had a problem with them, and they only had one barb on them. I do agree with using steel lines as much as possible, but a little rubber line won't hurt anything.

Inspect the original Packard oil cooler. Pass some Kerosene thru it to see if it is clear and that the sheet metal body of the OEM oil cooler is not rusted.

On one hand i can agree with Craig about questionable condition oil coolers. On the other hand i agree with Owen. If the OEM oil cooler is in good condition i'd stay with the OEM. Maybe add the auxilary as long as it is getting good air flow even when car is stopped and idleing.

I replaced the radiator in my Exec with a ford radiator that had the cooler built into the bottom of the radiator. That's the only reason i eleminated the OEM Packard oil cooler.

Check the ID of the OEM tubeing comming from the trans. If the hose shanks ID is more than 10% smaller then may be need to use some other means of connexion. Don't restrict the oil flow by using fittings with significantly smaller ID.

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When I asked an old transmission repair man about installing a cooler on my Motorhome in addition to the rad cooler he pulled the tranas dipstick out and held the tip with thumb and forefinger and said. " If you can hold the tip without burning yourself then you don't need a trans cooler" Last March in Rocky Mountain National Park in Colorado I drove the old Chev 350/TH400 motorhome up to over 12500 feet above sea level mostly in 2nd gear and at the top of the mountain checked the trans dipstick. I could hold the tip with it with no problem. My experience is that unless you are pulling a trailer the radiator type trans coolers will maintain the trans fluid at a temp that will do no harm and I have never had a trans fail because of overheating in all the cars I have owned. I have never driven a car across Death Valley in 120F heat so may I am wrong but I suspect that the Packard engineers knew what they were doing.

I'm not sure the hose shanks are a good idea either. Use steel tubing w/double inverted flare all the way like original and as so many other cars do from the factory

With the original heat exchanger, the transmission and the exchanger were essentially part of a single unit assembly so with steel lines there would be little or no movement relative to the lines. But as soon as you go to an air cooler mounted to the body and not the drive train, you will have repetitive movement so either rubber lines or a rubber flex section would be simple, good engineering practice.

As to flare or barbed fittings, just check what pressures are involved and that should dictate the choices.

Good point Owen.

However, many production cars with trans oil cooler at bottom of radiator run soild lines to the radiator which does not move with the engine.

I'm guessing that production cars (most i've seen) can get away with the solid lines to the bottom of radiator because the lines are so long.

Kevin, just make sure that THE hose shank ID is not less than that of the feed lines.

Let's try a little common sense rather than some psuedo engineering. Examine the following statement.
The original water cooled cooler is not a cooler, it's a heater. It heats the trans fluid with hot water and heats the water with hot trans fluid.
In the Packard system water from the block flows down thru the radiator, up thru the trans cooler and back into the engine.
In the systems of most other manufacturers, the water flows down thru the radiator, thru the integral trans cooler at the bottom of the radiator and back into the engine. The hot water from the radiator flows thru the trans cooler. Now I am not an engineer, not even a psuedo one. But explain to me the apparent HUGE difference in these two approaches to the same problem. I do think an auxiliary transmission cooler is a good step and I have one on both vehicles. But I don't need to disparage the manufacturer to justify it.

That the factory-installed coolers are failing after 50+ years shows poor design and terrible quality on the part of the manufacturer - NOT!

Seriously, I'm in agreement with Owen and Randy.

I'm not a mechanic by trade, but all other vehicles that I have worked on (or looked up the relevant parts for) and were equipped with a water-cooled engine and automatic transmissions have also had the trans fluid coolers mounted in the coolant stream, but in one of the radiator tanks. Heck, in more recent years, some vehicles even use the other radiator tank for an optional engine oil cooler. Yet, I've seen leaks occur in radiator-mounted coolers in less than 10 years - even in vehicles with plastic tanks. That's why cooling systems should be pressure-checked periodically.

I'm no engineer, but if the coolant entering the water pump inlet is good enough to help cool the engine, why wouldn't it be good enough to cool the trans fluid? As previously noted, no one has provided any empirical evidence, but thanks to Clipper47 for a good tip on assessing the need for an auxiliary cooler. If anything, I'd think that, as positioned on the Packard V8, the trans cooler would get the lowest temperature of all coolant in the total circuit. It's hard to imagine that the coolant would pick up any more heat from the Ultramatic's fluid than from any other tranny with cooler in one of the radiator tanks.

Yet, who can rightfully say that trans fluid coolers that rely upon engine coolant for thermal exchange aren't also intended to help warm up fluid as well? Consider that trans fluid serves a lubricating as well as a hydraulic purpose, and cold, thick fluid doesn't lubricate as well.

Meanwhile, I've only ever seen air-cooled trans fluid coolers installed ahead of the radiator by the factory as an AUXILIARY unit and inline with the radiator-mounted cooler - typically for vehicles intended to tow or carry heavy loads. I'd be surprised if B&M and other suppliers of such coolers didn't recommend retaining the factory-installed unit and using theirs in conjuction with it. That said, I wouldn't be averse to installing an auxiliary cooler for severe usage, whether that be to accomodate for load or ambient temperatures.

Still, after 50+ years, anything of a mechanical nature can fail; it isn't always about miles. Personally, I would want to find out what failed in the stock cooler and repair it.

Are the halves of the Ultramtic cooler tank welded or sweated together? Is the trans fluid passage in the cooler just a piece of steel tubing running in a zig-zag path? If so, one could replace that with something more resistant to corrosion. Many parts stores now offer a corrosions-resistant copper-nickel coated steel tubing that's easy to form - quite popular around here for brake and fuel lines on daily drivers (due to the use of calcium chloride and salt-brine in winter months). While I'm in there, it shouldn't be too difficult to fabricate and install new inlet/outlet coolant pipes for the cooler.

Sounds like it could be a good rebuilding program for one of the established Packard vendors.