Classic/Antique Car Repair: Hot Rad?, radiator repair shop, pontiac laurentian

Question
Hi Dick
My 64 Pontiac Laurentian has been running OK all summer.
Just lately I noticed white smoke coming out of the oil breather cap and the oil dipstick tube.
Thinking I may have a bad seal I got some GUNK CYLINDER HEAD SEALER and followed the instructions. I double checked and it all looked good until I went for a test ride and blew a hole in the main rad(the fat one) hose!
I took it to the local shop.He replaced the hose and pressur checked it and it was good.Also,the engine itself wasnt overheating(in his opinion as the temperature gauge dosnt work).He replaced the coolant and it wasnt that hot after running the engine for a while.The rad itself though was very hot to the touch.
All he could recomend was replacing the rad.Fairly expensive,as I would have to get one fabricated.
I would appreciate your opinion.Thanks!

Answer
Hi, Barry - haven't heard from you for a while.

Your mechanic may be right, although I don't know why the whole radiator would have to be replaced. I think if you take it to a radiator repair shop they can "rod it out" or if it's too far gone for that, they can order a new core for it and rebuild it - that should be much less money than a whole new radiator.   I also beleive that new radiators are probably available, assuming it is the same as used for a same year Chevrolet - there are very good supplies of replacement parts for US built Chevrolets.  I would expect a complete brand new radiator to cost somewhere around $450 US, and you could install it yourself.

Before you do any of this, though, go to your local supermarket housewares department and buy yourself a "candy thermometer".  These look like a giant fever thermometer like your mom stuck under your tongue when you looked feverish, but it is about 16 inches long and about 3/4 of an inch in diameter.  It will accurately measure temperatures way beyond boiling, so you can safely stick it in the top of your radiator in place of the radiator cap (don't slam the hood on it!) and then run the engine long enough for the temp to climb up and stabilize.  I don't know what thermostat is in your car, but assuming it is a 180 degree thermostat, the temperature in the top tank of the radiator should stablilize around 190-195 (or about 15 degrees above whatever the thermostat is rated at. If that is where it is running, I don't see the problem.

Let me know what you find out, OK?

Dick