just purchased the truck and wondering what is on the top tank of the radiator with a pipe that vents to atmosphere.
That is the pressure relief valve for the radiator. By 1952, GMC started using a "regular" radiator cap that combined a filler with a pressure relief valve. Take your radiator cap off and note that it doesn't have a pressure relief valve built it. Also note the valve just to the passenger's side of the radiator cap. Its purpose is to allow checking coolant level without removing the cap. Just barely crack it open. If liquid dribbles out the radiator is full.
Did some more research and found that the pressure relief valve (ie. pressurized cooling system) was standard on 300 series and larger trucks. It was optional on 150 through 280 series trucks. All of these had a "port" on the top tank of the radiator that could be equipped with the pressure relief valve.
When you're ready to upgrade the radiator, Cold Case makes an aluminum radiator that drops in nicely and cools your engine much more efficiently than the old stock ones. Has the same look as original( shape). Living in South TX, you meed all the cool you can get and $370 for this upgrade was well worth it.
Is this the radiator you're referring to? 48-54 GMC Truck Aluminum Performance Radiator | Cold Case Aluminum Performance Radiators Hard to tell from the picture, but it doesn't look like it's right for GMC - bottom of the radiator is supposed to kick forward in the bracket to provide room for the L-O-N-G GMC six cylinder. Is this intended for V8 swapped trucks only, or is the picture not right?
Item Description Price Qty Total I odered mine from Chevsofthe40's. Here is tjeir order number. 3118968AG 48-54 Radiator (Aluminum) 2 Core GMC Truck $398.00 I think its the same one but just to be sure... mine dropped into my GMC no problems. We did have to drill some new holes to mount as every truck this old will be a little different. However, installation was easy.
Awesome, thank you - and to confirm, you're still running a GMC six cylinder? Would love a picture of fan-to-radiator clearance, if you have a minute.
My truck is a Canadian so came from factory with Chevy 216. At some point this was replaced with a 235 which it still has. When I replaced the fan blade with an 18" 6 bladed fan, I had to use a 1" spacer to push the fan closer to the radiator and align the pulleys. I think that even with the slightly longer GMC motor you are going to have more than enough space. I think the difference is that you may not need the spacer. If you are in a warm climate, go ahead and replace the fan also. The original fans move much less air across the radiator; fans available now do a much better job.
