The PO decided to not use the factory installed coolant tank for some reason. So the car really does not have the correct amount of coolant in it. Maybe because the cap was junk...I don't really know. I pulled it out cleaned up the dried crusty old coolant that was left in there, and bought a new cap. Cap is not an exact match but it should work fine. My question is, what is the process to properly fill it? Just top off the Radiator and let it spit in there from the tube?
The level of coolant In the rad is what matters most. the rad should have a cold line on the tank below the cap. That cold fill line is usually about 3” below the top of the tank. the over flow tank should be filled about half way.
IIRC the cold line is only on vehicle's with out a over flow tank..... Both of my NON factory 67 gs 400 4 core rads do not have a cold line....
A properly assembly and operational cooling system coupled with a correct expansion/overflow tank, will "correct" any issues with coolant level in the cod system. When the car is driven to full high temp range, coolant is heated, and the car/engine is shut down, steam is released once the pressure exceeds the radiator cap rating, coolant/steam is released from the radiator (and engine) to the overflow tank. As the coolant in the engine creates a low pressure condition (vacuum), coolant in the overflow replenishes the coolant into the engine (cooling system). So, overtime, a properly operating coolant system, will eliminate any "air pockets" and normalize the cooling system to it's best state. The manufacturer's engineers got paid lot of money to figure all of this out First, follow their lead. Second, if after following that lead you see a trend that is contrary to the design and desired outcome, investigate with intelligence and purpose, Identity problem(s), and formulate and verify solution. But, for all that is sacred and holy, stop grabbing at straws or randomly throwing money, prats and silly ideas at the issue, hoping it will produce anything useful... (Vehicles that did not originally come with shroud for fans, overflow tanks, seat belts, collapsing steering columns and many other things added later may well benefit from adding them. Do not limit an improvement because it was not "fac-tree" on your specific vehicle. (Concourse entry and judging is an exception...)
If you don't mind wasting a little coolant, the system will self-balance in a few heat cycles by filling the radiator 100% to the brim and adding enough coolant to get the overflow tank to 1/2 capacity. After a few heat cycles, it will stabilize to the maximum the overflow tank can accept from the hot radiator before it overflows. If the system has no leaks, this is the equilibrium point where it expands but loses no coolant and contracts to refill the radiator each heat cycle.
Fill the radiator to about 3" below the neck. Run the engine to operating temperature with the cap off. Fill the radiator as high as you can with the engine running at idle. Then have someone rev the engine to 1500 RPM and hold it there. The coolant level will drop inside the radiator, and you will be able to add more coolant to the radiator. Fill it to the brim, put the cap on, and then have your helper release the throttle. Fill the overflow to 1-2" above the cold line. After a few heat cycles, the level in the overflow will stabilize. When at operating temperature, the level will be higher, when the engine cools, the level will drop.
Right I have no cold line on the Rad. I just have an add line and a full line on the plastic reservoir. It is original corroded plastic cap and all that I just replaced.
Thank you! I will do this. I have been paranoid about overheating (living in Florida), thats the last thing I want. Really appreciate the responses. Next will be gauges for peace of mind.
