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

As to newly (and correctly) rebuilt engines creating so much friction that they overheat, rememeber that when the car was brand new from the dealer and youdorve it home for the first time , it did not overheat!

Fred - I think you misinterpreted what I said. Of course they didn't boil over when driven home from the dealers. The point was that, at the time the engine was new and tight, the cooling system was also new and completely competent to handle the load imposed on it. It's unlikely that the cooling sytem remained that competent by the time an engine overhaul was needed. That was the point. Sorry if I didn't state it clearly enough.

Did your rebuilder boil out the block and clean the water distribution tube? Just general questions trying to help.

As for the size of the radiator. Most cars that offered optional engines, all models used the same size rad as far as height and width. The difference was in the thickness of the core. For the fin and tube type used from the late fifties up, common sizes were 2 core (six cylinder) 3 core (V8) and 4 core (heavy duty, trailer towing package, station wagon and big block engine).

If the water tube is left out or rotted away the coolant will stream up the front of the engine and not reach the back. The back of the engine will be boiling while the front is cool.

Perhaps some owners of the same model can tell you how thick their rads are.

Interesting. The old cap is a 7 psi type, with a dimension of 7/8" from the rubber gasket under the top to the bottom of the seal. The cap I just bought is a 13 psi type, but it's only 3/4". I see on the part x-ref section, a Stant 10206 or Napa 403-1411 7 lb cap is listed for the 48-50 ,and Balkamp 7031461 or Stant 10229 13 lb cap is listed for the V8. Any suggestions for the 51?

I think I would like to try the 13 lb version.

I will also pull the water pump as my next option to check it out. Terrill Machine rebuilt it about 3 years ago.

The block was boiled out prior to rebuilding, and I put in a new water distribution tube, even though the old one was in good shape as well. The exhaust heat riser valve is in good working condition. The thermostat was replaced, and I drilled a small hole in it to assist with preventing air locks.

thanks for the advice.

Don't use the 3/4 one, find an inch one. I used a 3/4 one and it was great for half hour tuning sessions...once i got about 20 miles up the road, started finally getting warm and blowing coolant out. If you use the short one, the coolant has a direct path without pressure to the overflow, and i don't think just the top gasket does much.

Again I ask how hot is "too hot"?? Perhaps the problem should have been stated the water comes out the radiator neck.

Following a logical diagnosis technique saves an awful lot of keystrokes

While on this topic, I have a '48 Deluxe Touring Sedan with a 288. It came with a spare radiator which has a thicker core (fills the side bracket width) than the one installed in the car (doesn't fill side bracket width by one row). Both fit, and work equally as well. Which is the correct one for this car?

As the 288 is the smaller motor, I believe th thinner one is correct

Quote:

Why the higher pressure cap? You may run into problems with a 13 lbs cap in a system designed for a 7 lbs cap. For one thing, the radiator and heater core are not designed for a sustained high pressure. I recommend you get the correct depth 7 lbs cap and see how it performs.

(o{I}o)

Further on the 13# cap "solution"

As I have said, diagnose the problem and fix it. If a car bottoms out adn you increase the tire presure to 100 pounds, it may raise it just enough to prevent that. You will undoubtedly crack the wheels and the tires will explode. The correct way to diagnose it is to see if there is excess weight in the car( sandbags in the trunk) or the springs are sagged.

Packards and lesser vehivles are logical beings, treat them as such and they will give a liftime of pleasure. Except of course '56 with pushbuttons