When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Dose the radiator draw in coolant from the overflow? I have a small leak by the water neck. Never drips, just collects on top of the water pump. I have coolant in the overflow but the level never changes. It this plumbed correctly? Should the radiator draw in coolant?
the overflow tank or burp tank or whatever you want to call it operates as such,
When the engine heats up the coolant expands. This has to go some where since liquids do not compress it is forced out to the overflow tank, when the engine cools and the coolant retracts it is drawn in from the over flow tank back in to the cooling system.
Before we had over flow tanks (prior to the late 60's) you would have to top up the cooling system on occasion cause as coolant the expanded it was just expelled on to the ground. So usually when an oil change was done, it included topping up the cooling system as you would end up with a pile of air in the system....
The over flow tank is a good way to see if you have coolant leaks internally (or externally) if the level in the overflow tank drops then you know you have leak some where. Since yours does not appear to dropping the leak must be very minor.
You need to make sure you have a recovery type cap. If you get a cap for these year trucks, it will be a recovery type cap.
The cap needs to seal well against the top of the radiator neck, this is a different seal than the one that pressurizes the coolant system on the bottom of the cap.
You also need to make sure that little hose going to the tank is in good shape with no holes and is clamped to the radiator nipple. And make sure the end that is in the tank is submerged in coolant. If it can suck air rather than the coolant out of the tank, it will do that instead of drawing the coolant out of the tank
And last but not least, when the engine is cool take the cap off and fill the radiator as full as you can get it. If there is a lot of air space in the top of the radiator it will not pull any coolant from the tank.
There has been some debate on this before, the tanks on these trucks have no easy fill cap and no level lines on the side of the tank. It seems like they were really just a catch tank to keep the coolant off the ground, but if you do all the above, you can make it work like a recovery tank.
