Re: Engine Cooling Concerns

Posted by HH56 On 2015/4/5 11:54:56

No factory shroud although there have been some fabricated by owners and one aftermarket "one size fits all" type frequently found on ebay, Little late now but I'd be curious how far your fan normally sits from the core. Most are less than an inch but some models were quite a bit farther away. Another common problem is the water distribution tube. Make sure it is clean and in good condition -- also water pump impeller is tight and nothing worn to create large distances between it and the pump casting and cover plate.

IMO, it would be a good idea to change the thermostat if it is the old bellows type. They are inexpensive enough to just change it even if not that old. You can then make sure it is the correct one or even select a cooler temp range. Standard was 160 but Packard offered a lower temp of around 150 and higher around 180.

The thermometer could be an issue. The electric type can drift and also read incorrectly if rust or grease interferes with ground to the sender. Bad or dirty connections elsewhere can also affect the reading. Believe that particular sender is the long bimetal type rather than a short pure resistance type. If so you will not be able to get a good resistance reading since it is basically an on/off operation. The water temp and a heater affects a bimetal strip in the sender which changes the frequency of the on/off. The on/off time allows the gauge bimetal to heat or cool and determines how far the needle will deflect.

Sometimes having a mechanical thermometer permanently installed and hidden is an advantage to double check the electric. Unfortunately there is no easy way to install a second sender unless it is in a radiator hose or an adapter is made to go under the thermostat housing.

EDIT: along with O_Ds recommendation on the radiator gravity test is a question of is the radiator itself correct. Is it the original? One poster had frequent and longstanding issues with his 56 overheating. Had done everything recommended and possible to find the problem and was finally contemplating getting an oversize radiator made. Upon opening the radiator the shop found that at some time in the cars past someone had replaced the original radiator core with one considerably smaller. Haven't seen any recent posts from him but last I heard a correct radiator solved the problem.