Re: flat towing & cooling?
I've been reading this 'cooling' thread, with interest. I've got the same cooling problem, and I've been trying everything but the new radiator. Specifically, the truck is a 69 C-20, with the 350. I've had it since new, and recently I've had the radiator cleaned, changed the water pump and t-stat a couple of times, and I've added the 'bleeder'-lines that pick up at the rear of the heads, through the intake manifold, and feed to the inlet of the radiator. I've been dragging my feet on the new radiator, because, according to my local parts source and radiator shop, the core that I already have is the biggest available, and the one originally intended for the factory-installed 396 (it's a 4-row). I have been told that if I ask for a 454 radiator to fit my truck, it will come as the same one I already have. When towing, it runs hot... over 220, just on the level, and easily passing 250 on a grade. I've also melted a couple of exhaust manifolds pushing it on long grades. It sure seems that I need more radiator, but I also wonder if there is anything else. The melted manifolds could indicate other problems. I've checked timing many times, and it seems that it is ok. I've got a HEI on it, but I am thinking of going back to the points, to see if there is any effect. It seems to be running richer than when it was new. It used to burn the tail pipes to light grey, but now all I see is black. Mileage has been consistently lousey... around 8-to-9 towing, and an easy 12 empty. Any new thoughts?