1940 Packard 120 - 1801

Does anyone here know if the radiator is a pressurized system in my car? If pressurized how many pounds?

I recently purchased the Packard and when it warms up - water slowly runs out of the overflow tube. The radiator cap on it now does not reach the seat of the fill hole.

No, is is not pressurized. Packard started using pressure systems in 41 or 42 and that was using a 4 1/2 lb cap.

What is your engine temp running?

Likely you are filling the rad too full and not allowing adequate space for expansion as the water temp increases. Or possibly a leaking head gasket?

As 32 said your water level cold should be about a 1/2" below the lower hole in the neck.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">No, is is not pressurized. Packard started using pressure systems in 41 or 42 and that was using a 4 1/2 lb cap. </div></div>

Nooooooo! I'm not sure about the six-cylinder 110s, but all of the eight-cylinder Packards were pressurized in 1940. You are correct in that it should be about 4 1/2 pounds. A deeper fitting cap is needed.

suggest you ask for a refund on whatever reference source you used to make your determination that the guy's 1940 Packard did not have a pressurized radiator. Or, if you relied on an individual, may I respectfully suggest you catch him for info BEFORE he starts sniffing that stuff.....!

Seriously, Packard went to pressure radiator caps in 1938. Well - let me qualify that...I never paid much attention to the "small" Packard line - cant recall when they got pressure caps. That was the first year Packard's hood ornament was NOT also a radiator cap (on their "big" car line).

And, yes, it was a four & a half pound cap.

Additionally, beginning in 1938, the "big" Packards (again, not sure about the so called "Juniors") not only had a pressure cap, they also had an over-flow tank so that expanding water would not be lost. I cant recall now about whether the 1940's came out of the factory with that over-flow tank used on the earlier "big" Packards.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I can't recall now about whether the 1940s' came out of the factory with that overflow tank used on the earlier "big" Packards. </div></div>

Nope. No overflow tank on the 1940s'.

yeah - makes sense - the 1940 "big" cars had a much smaller engine then the "big" 1939 cars, so with a much smaller cooling system = less water to expand = less expansion - so the top tank of 1940 and later radiator was sufficient to handle the expansion-rate of warmed up water.

NO NO NO...I am NOT making fun of the "356" engines. Over the years, owned many Packards with that engine - in fact, somewhere I read that the "356" engine, with overdrive, in a coupe body, would have been the world's fastest production car of its day. I'd match a bone-stock '40 or '41 "160" coupe with overdrive and a "356" against ANY pre-war production car, and I mean ANY, either in a drag race or "flat out". With its "insert" connnecting rod bearings (you Buick Century fans - you didnt get the benefits of "insert" rod bearings until the early 1950's !) and excellent cooling, the '40 and later "356" can go wide open FOREVER without coming unglued.

If you guys want to have some fun learning more about how pressurized cooling systems and "insert" type con rods make a big difference, go research some of the news articles on the opening of the first stretches of the Pennsylvania Turnpike..!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">somewhere I read that the "356" engine, with overdrive, in a coupe body, would have been the world's fastest production car of its day. I'd match a bone-stock '40 or '41 "160" coupe with overdrive and a "356" against ANY pre-war production car, and I mean ANY, either in a drag race or "flat out".

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Steve Snyder, in Orange, California, has one of those and that's exactly what he says, too. For those of you wondering why the o.d.-equipped cars would be beneficial in a drag race, it's because normally you got a higher ratio gear set in the rear end, so that without the o.d. engaged, you have a lot more torque.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">somewhere I read that the "356" engine, with overdrive, in a coupe body, would have been the world's fastest production car of its day. I'd match a bone-stock '40 or '41 "160" coupe with overdrive and a "356" against ANY pre-war production car, and I mean ANY, either in a drag race or "flat out".

</div></div>

Steve Snyder, in Orange, California, has one of those and that's exactly what he says, too. For those of you wondering why the o.d.-equipped cars would be beneficial in a drag race, it's because normally you got a higher ratio gear set in the rear end, so that without the o.d. engaged, you have a lot more torque. </div></div>

Not only that you can shift from 2nd to 2nd overdrive After 22mph or so and that gear can be held up to well past 60! I rarely but occasionally get into little impromtue drags with my '47 and that "long" second gear is a real advantage. Zero to 60 in 19 seconds can still be a fun ride! <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

West, you are sooooooo right on the pressurized cap for the 40, my bad <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" /> I forgot I put a 39 radiator in my car <img src="http://forums.aaca.org/images/graemlins/shocked.gif" alt="" />

It was 39 and before that had the filler neck using the inside ears style of non pressure cap.

The only other cap for 40 was a 12 lbs cap for the air conditioned cars.

I guess that means I need to look for a 12-pound cap????

Don't know, but I seen references to 4 1/2, 7 and 12 lbs for the 40-42 years.

JT - I remain confused by your posts. Packard went from non-pressurized to conventional pressure caps in 1938. A 1939 and 1940 radiator would be similar, if not identical for any given series Packard engine .

Both '39 & '40 were pressurized, and both had their filler necks UNDER the hood - not like the 1937 & earlier, the last year where the radiator cap was also the hood ornament.

West, I did find this from the Packard Technical Service Data Manual dated 1940,

"Pressure caps are fitted to the super-8's and weather conditioned one-tens and one-twenties. These cars have special radiators to operate under pressure. The radiators on our other cars are not intended to operate under pressure. Do not attempt to fit pressure caps to cars not originally so equipped."

Okay.

Do you have a date from when that letter was sent. It's still possible that later model 120s and 110s from 1940 were updated with pressurized radiators, as this was the type of change that would have been made "on the fly" when the old parts supply finally ran out.

It looks like it is from 7-40 so it could have been a mid year change. I ask some other 40 owners I know.

Good information. That's pretty much the end of the run for 1940, so it might be safe to say that 110s and 120s from 1940 (without a/c) were all non-pressurized cars.

I'm still curious about the 12-pound cap, though.???

now..LISTEN UP..you guys...dont any of you try and twist my comments about which Packards had pressure caps, and which didnt...into a food fight ! As I noted in my above "post", my memory is not all that clear on the "baby" Packards, not surprised to learn the "baby" Packards did NOT have some of the technical features we snobs had for our "big" Packards! (incidentally, the "baby" Packards actually had more advanced technical features in some respects, when they first came out, than the "Senior Division" cars !

So - please...PLEASE do NOT get the idea I was looking down on the pre war "baby" Packards because I didnt know that they didn't have the pressurized cooling systems of the "big" Packards!

Packard died for other reasons in a far different world that followed World War II.

Seriously..I was actually BORN in a 1936 "120" ! There is NO question in my mind, that Packard survived the 1930's because it decided to enter the middle-price range. I will match that '36 Packard "120" we had for many years, against ANY car of its year in its price range. I dont want to be responsible for turning the focus of the original question in this "thread" into other areas, so I will have to again emphasize that as to the technical features of the smaller-engined Packards, I simply dont know or remember enough about them to make further useful contributions on this particular subject.

Pete

Between your knowledge and mine, I think we had the senior series cars pretty well identified. I didn't think we were throwing food. I was just trying to find the answer to the smaller cars, which I think JT has now answered with the factory service letter... at least through 1940. Or am I missing something?

What has me confused is JT's comment about 7 and 12-pound caps. I would like to learn more about those.

beats me...West..I never heard of a 12 lb cap for pre-war cars.. ? ? ?

The 12 lbs cap info I have in front of me is from the 1942 Packard shop manual that specifies a standard 4 1/2 lb cap with this notation, "air conditioned cars are fitted with 12 pound per square inch pressure caps."

fascinating news - didn't know that - I knew Packard had mechanical refrigeration prior to the war, but never actually saw one.

The Packard Mechanical Specifications for the 18th series (dated 8-39) does not specify radiator cap type whereas the specs for the 19th (dated 9-40) and 20th (dated 9-41) are pressure types as mentioned in the post above.

Out side temp is about 60 degrees - Radiator water temp 170 degrees. The water level is down about 2 1/2 inches before it stops dribbling out.

At this point I,m totally confused. It doesn't have an overflow tank. The only pressurized cap I can find for a 1940 120 is for the Clipper model. Gentlemen I thank you for your help. Perhaps things will change when the weather warms up, but for now I'll keep 2 gallons of water in the trunk. Head gasket is OK - no water in oil or oil in water.

One eye on the road and the other on the temp gauge.

Thanks for the responses

Radiator cap part numbers from the Twentieth Series Service Parts List, issued May, 1942.

Is it of any use?

TG

I think you might need a deeper radiator cap that seats correctly in your radiator neck. It sounds like you have a pressure system. A common problem with these cars is that the radiators get clogged over the years and that may be part of your problem also, giving you less flow, and forcing out fluid as it heats up. You might try flushing it out also and see if that helps. The only pre war Packards I know of with overflow tanks were the 32 - 39 12s and they were not pressurized.

I had the same problem with the radiator on my 1950 Standard Eight (which has the 288 cubic inch engine). To try to get an overheating problem under control, I had the cooling system backflushed and the water pump replaced. I still ended up losing a lot of coolant, which, of course, exacerbated overheating situation. Warm weather just made the problem worse. But when I replaced radiator cap the problems largely disappeared. Turned out the existing cap was not deep enough and did not pressurize the system. I still lose some coolant on days when the temperatures are in the 80s or higher, but thankfully, those days are rare for me!

All the best,

Mark in Alaska

Dave is only partially correct - in fact, for the 1938-39 production, all Twelves had full pressure cooling. '38 - '39 Twelve radiators carry the same part number. Now, in fairness to Dave, the 1937 and all earlier Packard Twelves did NOT have pressurized cooling systems.

Why is this interesting ? The introduction of presssurized cooling systems permitted higher running temps. The faster you can get a motor up to operating temp, and the higher you can set that temp, the more effecient. The introduction of pressure radiators was but one of a whole bunch of incredible technological advances interrupted by World War Two, that gave us our modern short stroke "high rpm - severe duty capable" motors we have today.

Packard moved the radiator cap under the hood on the 38 and 39 12s, they didn't use pressure caps as they did on the 40 41s, and the cooling system is the same as the earlier cars, at least on the 8 38 & 39 12s in my care.

Dave - how's your sense of humor...may I tease you about that flat statement of yours ?

You have EIGHT '38 - '39 Packard Twelves that do NOT have pressurized cooling systems ? That is interesting.

Seriously, in fairness to Dave, for some reason Packard's technical writers were bashful about the new pressurized radiator filler cap and neck system for 1938; for some reason they did not SPECIFICALLY use the term "pressurized cooling system" in their literature when referring to this change.

Hopefully, Dave wont mind being teased - should I suggest that I guess the radiator upper "filler-neck" in my own '38 Packard Twelve was custom-built just for me to beat up on Dave with, (as was the many dozens I have worked on down thru the years? ).

My own raditor, and all the '38 Twelves and Super Eights I've seen, differ from 1937 and earleir "Senior" Packard production, in that they have the bottom "seal plate" for the spring-loaded pressure cap to "bottom" on, clearly was designed for a pressure radiator cap.

What appeared to be original pressure cap on it when I got it in late '54 started to leak pressure as its sealing rubber went bad - replaced it several times over the years.

Can I tease Dave about that special "custom-built just for my own Packard Twelve and the many dozens I have worked on", publication by Packard, its "tech. specs" known as the "1938 DATA BOOK FOR THE PACKARD TWELVE AND SUPER EIGHT" which refers (see Pp. 33 of the tech. specs. on the cooling system) "the air to boil temperature has been raised almost 10 degrees higher which gives cooling capacity for a much wider range of driving conditions"...

C'mon...Dave..how do you think you raise the boiling temp. of water..!

I know this is an old post but as I am just getting back into this forum after years of absence, here is my two-cents worth. My 1940 110 that I owned for close to 40 years had the 4 1/2 lb cap mentioned and it required a long cap to reach the bottom so if you didn't use the right one, the coolant would simply come out the overflow. Although not original, I took the radiator to the shop and had a more modern stem installed and it worked perfectly. The difference was hardly noticeable but once I accidentally put on a 12 lb cap and saw the upper tank start to expand as the engine warmed up! Another moment and it would have burst so never use more than the 4 1/2 lb cap that it was designed to use.

My 1938 1604 Super 8 convertible coupe does not have a pressurized cooling system.....and there's nothing to suggest it ever did.....just for reference....

I installed a 7 lb cap and an overflow tank on my 1801 and it works very well. The tank and hose were less than $15. I cut the over flow tube at the radiator cap, clamped the hose to it and hung the tank on the fire wall.

Bobhattler

Sanford NC

1940 Packard sedan convertible 1801

1948 Willys CJ2A