Packard Forum Index » Post-War (1946-54)

Well I was able to take it out for a spin and let it idle.
It didn't overheat after a half hour in idle. Maybe the fact that it is about 20-30 degrees outside helps.
The UV temp gun shows the front and rear ends of the block 180 and 183 after sitting. The auto trans cooler lines were around 115. Looks pretty normal to me. The gage show the temp just past the middle at 190. The middle of the gage is 180 as expected. Not one to argue with success but I really expect to be calling AAA on the next warm day. I am going to run it in a heated garage and see if it acts up. And yes the door will be open with the exhaust plumbed out. :)

Where can I find a 6v fan for the radiator ? I haven't had any luck finding one. That is a good idea.

I have a 180degree thermostat. Maybe I'll go to the 160.
Do you have to use the old style thermostat or can I use one of the newer types ? Paid a lot for the original style.

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You should be able to find a 160F thermostat at Max Merritt or Kanter's.

Did you check your radiator cap for the right length and pressure?

I have seen the 6-volt electric fans advertised on the Internet, but can't recall which site. You may want to consider a flex fan first.

Good luck.

{o {I} o)

I'm beginning to wonder if there is anything wrong at all. It is not unusual for the temp to climb a bit when you slow down from high speed. There is a lot of heat stored in the engine block and head, when you slow down the water pump and fan slow down and the temp climbs temporarily.

Depends how bad it is. Does the rad boil over? Does the gauge shoot up to the danger area?

If it only goes up a bit and comes down in a few minutes I doubt anything is wrong.

6 volt fans are available from Fifth Avenue Internet Garage
at www.fifthaveinternetgarage.com This is also the place that sells head light relays to use to install fog lights.

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I agree with this. If the radiator is not boiling over then it is not overheating. One question I have here is why is it suggested to change the thermostat from 160 to 180 when the weather changes? Either thermostat will be completely open ( except maybe in sub zero climates) when the engine is warmed up no mater what the outside air temperature is. Why not just leave in the 180 degree thermostat if that's what the book calls for? Changing the thermostat doesn't change the operating temperature of the engine at all. It only changes the bottom temp which may, in cold weather, give you less heat out of the warm air heater. The thermostat has more to do with warming the engine up to a minimum temp faster and less to do with holding the temp down. It can't do that. Only the radiator can take heat away.

I sure get carried away at times.

When the temp gage is straight up it is at 180deg
a little past that is 190. The needle goes completely off the gage when it is overheating. I reached in to put a wire back in a clip on the control arm and received 2nd degree burns on the back of my hand. I think there is an overheat problem. Maybe a fan with more blades is the answer although I have never come across one in my quest. Anyone know where I can find one ? Flex fans will only help if the pitch of the blades is greater than the original which isn't likely since the original almost hits the generator already. I saw the electric fan (thanks for the link). Rather pricey isn't it. Guess it is cheaper than a head gasket ;)
I agree with what you said about the thermostat. It does control the warmup rate, however it should also keep the engine at the lower temp while driving if the cooling system is sufficient. I was wondering if the engine would stay at 160 degrees with the 160 thermostat. If nothing else it give me more time to pull off the road.

There is one problem with installing an electric pusher fan, that is that you're just masking whatever the original source of the problem is, and it's still there. Kind of like taking a Darvocet after you sprain your back splitting firewood, so you can go back to the woodpile and whack away some more.

You really need to get to the root cause of the problem. As to a better fan, I mentioned before about the Custom 8 (356) fan; I don't know if they fit the hub (think so) and have enough clearance at the sides (356 radiator is larger), but they have 5 blades and move a bit more air. Won't be easy to find one though, but occasionally I've seen them on eBay.

forgot to ask.. The napa thermostat you purchased. Was it a std thermostat for an GM V8 or was it for a Packard ? Curious because they really did look interchangable when I replaced mine. To be "safe" I ordered the packard original type. I have a draw full of the GM thermostats.
OTG

We don't change thermostats anymore. In the 40s it was customary to change them with the seasons. I suppose the idea was to get more heat out of the heater in winter and prevent overheating in summer.

Or maybe you were supposed to use the colder thermostat in winter to prevent boiling off your alcohol antifreeze? Until you brought it up I hadn't thought of this subject in 40 years. Now I'm not sure if you use the lower temp thermostat in summer or winter.

Generally speaking it pays to run the engine as hot as possible. Newer cars use high pressure cooling systems and hi temp thermostats for this reason. If you could get your old cooling system to hold 16 pounds pressure without blowing you could run a 195 thermostat. Your engine would run cleaner and produce more power and better mileage.

There may be a bit of confusion about what a thermostat does. A thermostat controls the minimum temperature of the coolant, not the maximum temperature. You will not prevent overheating by changing to a different thermostat temperature.
When I got my 1950 Packard last year I checked the thermostat and it was 180 degrees. I changed it to a 160 degree thermostat because I found that specified in a Packard book. If the coolant runs at a lower minimum temperature it will cost fuel economy and power because more energy is wasted to the coolant. However the lower mkinimum operating temperature requires more time to reach boiling if you run into a difficult operating condition such as extended idling or climbing a long steep hill.
I think the reason they used to recommend changing to a higher temperature thermostat in the winter was to make the heater work better. I cannot think of another good reason right now.
Modern cars use much higher coolant temperatures than old cars, which increases gas mileage, power, and reduces the required radiator size. However the system has to be sealed and pressurized to prevent coolant loss.