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mclairmo · 08-26-2009, 01:30 AM

I don't think you have an airflow problem since you have a mechanical fan and you still have overheating while driving around. When the truck is moving the force of the air through the radiator should be enough airflow even without a fan. I believe you have a coolant flow issue or excessive heat production. Make sure that your water pump pulley is significantly smaller than your crank pulley. This will keep the water pump spinning at the correct speed. Also, make sure that the water pump is working properly and that the impeller is not damaged, rusted or just free wheeling somehow. You may want to switch to a high volume unit. The Procomp one sold by Skip White and other Ebay vendors works well. Flowkoolers are nice, too. Make sure that the radiator is not clogged and the engine coolant passages are clear. Maybe try a good flush of the system. Make sure you are running a vacuum advance and that the carb is not running lean. Also, 100% water in the coolant system transfers heat best. Coolant is not as good at heat transfer, which is why you can only run 50% coolant. You need at least 50% water to ensure proper cooling. The coolant is actually an anti-freezing agent and includes a water pump lubricant and anti-rust agent. I run 100% distilled water and Water Wetter from Kragen or Autozone. Water Wetter eliminates the surface tension of the water so that it literally sits closer to the metal block and thus, transfers heat better. It also contains an anti-rust agent and water pump lubricant. This will cool better than anything else from my experience and is ok to use at race tracks that don't allow coolant. If you do run a T-Stat, use a high flow one, not the standard ones everyone carries. However, I am not convinced you need one out here in SoCal or Riverside. The purpose of the T-Stat is to allow the engine to get up to proper operating temp quickly so you can get going. Very necessary in cold climates and for best fuel efficiency. However, the T-Stat also restricts coolant flow and coolant flow is critical to cooling. The T-Stat can also trap air bubbles in the system which reduces heat transfer. In very warm climates where the engine will likely get up to operating temp without the T-Stat in a reasonable amount of time, I believe you can go without it. My truck does not have a T-Stat at all and it runs great, never gets too hot but still gets up to proper operating temp pretty quickly. I know others will disagree/argue with me but I've been studying/troubleshooting cooling system problems a long long time.

08-26-2009, 01:30 AM	#8
mclairmo Registered User Join Date: Jan 2006 Location: Take Off Posts: 1,908	Re: Cooling Issues I don't think you have an airflow problem since you have a mechanical fan and you still have overheating while driving around. When the truck is moving the force of the air through the radiator should be enough airflow even without a fan. I believe you have a coolant flow issue or excessive heat production. Make sure that your water pump pulley is significantly smaller than your crank pulley. This will keep the water pump spinning at the correct speed. Also, make sure that the water pump is working properly and that the impeller is not damaged, rusted or just free wheeling somehow. You may want to switch to a high volume unit. The Procomp one sold by Skip White and other Ebay vendors works well. Flowkoolers are nice, too. Make sure that the radiator is not clogged and the engine coolant passages are clear. Maybe try a good flush of the system. Make sure you are running a vacuum advance and that the carb is not running lean. Also, 100% water in the coolant system transfers heat best. Coolant is not as good at heat transfer, which is why you can only run 50% coolant. You need at least 50% water to ensure proper cooling. The coolant is actually an anti-freezing agent and includes a water pump lubricant and anti-rust agent. I run 100% distilled water and Water Wetter from Kragen or Autozone. Water Wetter eliminates the surface tension of the water so that it literally sits closer to the metal block and thus, transfers heat better. It also contains an anti-rust agent and water pump lubricant. This will cool better than anything else from my experience and is ok to use at race tracks that don't allow coolant. If you do run a T-Stat, use a high flow one, not the standard ones everyone carries. However, I am not convinced you need one out here in SoCal or Riverside. The purpose of the T-Stat is to allow the engine to get up to proper operating temp quickly so you can get going. Very necessary in cold climates and for best fuel efficiency. However, the T-Stat also restricts coolant flow and coolant flow is critical to cooling. The T-Stat can also trap air bubbles in the system which reduces heat transfer. In very warm climates where the engine will likely get up to operating temp without the T-Stat in a reasonable amount of time, I believe you can go without it. My truck does not have a T-Stat at all and it runs great, never gets too hot but still gets up to proper operating temp pretty quickly. I know others will disagree/argue with me but I've been studying/troubleshooting cooling system problems a long long time.