well, yes Tim, I got a little general there, which is why I added to check your own year manual - the operators manual gives the basics in terms of how the system works, but most years don't have all the exact specs, not sure even the shop manuals indicate pressure cap ratings, and while there are variations with model, it's usually with special equipment and the majority here are dealing with 1/2 and 3/4T basic trucks, few automatics or odd models or car rads
I believe in all years after 48, 160 was the standard stat for light truck 235's, if antifreeze is used, the common practice now although it was a new idea then so the "standard issue" would have been lower - I know the Deco years and before were no pressure systems [and much larger rad tanks], the 4# cap I thought started with the 'full pressure' 235 .... at any rate, I'd say the 55 under discussion should have a 4# max with a 49 rad, but with a later rad could use a 7# .... part of the problem with our mixing original year parts
my particular point has to do with overfilling, as I believe it to be the real problem many folks call "overheating", and the misconception stems from modern systems with a remote tank, the assumption being the rad itself is full to the brim and should be in all cases - with rads that usually have virtually no tanks except the remote [expansion] tank .... also use of a modern pressure cap [12-15#] on an original rad is the cause of more than a few leaky rads as they weren't designed for the pressures of higher temps
the case at issue here is simply the truck telling the operator what the correct water level is by burping out the excess - although of course there's no chance of evaluating the cooling performance with no thermostat .... the fact that the [apparent] temp never got above 190 indicates there's no overheating going on
Bill
