I recently purchased a newly restored 1950 GMC 1/2 ton pickup with a chevrolet 235 engine online from a shop in Ontario, Canada. The gentleman I purchased from could not have been nicer or more helpful in getting the truck through customs and delivered . My new truck was made in Canada and after spending 70 years there was restored there by Canadians. Everything I saw told me they had done a quality job and I was quite excited when it arrived in late May. BTW, I live in Houston TX.
On my first drive, I noticed that the engine was running hot but didn't think too much about it. When i looked under the truck later that evening I saw a puddle of coolant and started to get concerned. Over the next several days, I drove it a few times noting that it was overheating in less and less time. I checked coolant level and determined only that it may be too full and let some out- no change. I then drained the radiator and refilled with the exact right mixture of coolant and water and saw no improvement. My fan was turning and my fan belt was tight and I was sure the guys who restored her had replaced the water pump and thermostat so felt like they were not the cause. I could not see any leaks from the engine or hoses and all hoses and gaskets were brand new.
I wanted to eventually add Vintage Air to the truck and so decided to replace the radiator. This did help in that it took 30 minutes to overheat instead of 10 but my problem remained. We checked the radiator/ coolant for oil and gas to insure I didnt have cracks in the head or block and those tested fine. While I started to price small block Chevy engines, my mechanic started removing the head and had it Magnafluxed to check for cracks. He inspected the head gasket(new) and found it was fine but went ahead and ordered a new one anyway just to be sure. We found no cracks in my 848 head thankfully. Then my mechanic put the new head gasket beside the one previously installed and we could see what our problem was.
The head gasket for a 261 had been installed purposefully to restrict coolant flow through the block. In cold climates you need it to run warmer as the cold air will keep it cool whereas in Houston- quite a hot climate- you need the maximum coolant running through. The 235 gasket was placed and she has run cool ever since.
Here is what I and the gentleman who sold me the truck learned: If you are buying or selling a truck or car and will be moving it to a much different climate, go ahead and change the head gasket to allow your engine to run as cool or warm as is appropriate. I was right that the men who restored and sold me the truck did a great job but I -and they- overlooked what now seems obvious - the climate difference needs to be factored in so you can enjoy your baby.
Hopefully this will help prevent someone else from making such a rookie mistake
