What should my water level be?

[woody82]

My truck keeps boiling water out of over flow tube Someone told me it needs room for air.But how much room?It only does it after you shut it off.

[catch2otwo]

You need a coolant expansion tank for the coolant to over flow into. When the truck gets hot, coolant expands and needs a place to go. An expansion tank catches this "expanded" coolant. When the motor cools back down, the coolant "shrinks" creating a vacuum. This vacuum then pulls the coolant from the expansion tank back into the motor.

Get expansion tank
Burp the coolant system
Replace the radiator cap if its old. If the radiator cap spring isnt strong enough to hold back pressure, it will not allow the coolant system to run at the correct pressure thus effectively lowering its boiling point.

*Your cooling system should NOT have room for air.

[woody82]

New cap new thermostat new head gaskets heads have been crack checked.This vehicle did not come out with a over flow tank.when coolant level gets down about 3-4 inches it don't do it.

[geezer#99]

If you don't have an overflow then the level will settle where it needs to.
In your case 3-4 inches down.
Just check it once in awhile as the air pockets burp out of the motor. You might need to add a little.

[FirstOwner69]

These trucks do not require a recovery tank and did not come with one. However, I believe that one was available as a dealer accessory. My 69 owners manual states: "On crossflow radiators, if the engine is cold, the coolant level should be three inches below bottom of filler neck or up to the mark on the side of the radiator."

I have always maintained mine that way (mark on the side of the 4 row radiator tank) and have never had an overflow or overheat in the 45 years I've had the truck.

[Razorbacker]

On both my trucks, one small block and one big block, I leave about 2-2.5 in of air gap from the neck. I don't have any issues with coolant overflow.

I believe on one or both of my trucks the radiators have a fill line stamped on the tank below the neck about 2 in.

[Andy4639]

In these times which we live in all cars and trucks should have a over flow tank no matter what year they are. Keep our environment clean as possible for future generations to enjoy!

On a side note. If you drive a older car to a nuclear power plant in the USA and it puks coolant out into the parking lot, security will ask you to either not drive it to work anymore are place a catch pan under it. Ask me how I know this?

With the political correct answer out of the way. Yes these trucks didn't come with a overflow but it is a good idea to put one on them. It's cheap insurance you will not run hot. The water level is about 2-3" below the cap when cold. But even a good system is going to lose water over time. You will have to add water at some point. The over flow to aids a quick way to tell if there is a problem in the cooling system also. It's safer to add water into the over flow than to the radiator if it's hot!

[In The Ten Ring]

Andy is right on the money. AND if you lose anti-freeze and a dog comes along, you might end up killing it.

Once my truck is running, I am going to make an overflow take out of PVC pipe and mount it to the radiator core support. There was a thread on here about it but I can't seem to find it.

[Andy4639]

Originally Posted by In The Ten Ring

Andy is right on the money. AND if you lose anti-freeze and a dog comes along, you might end up killing it.

Once my truck is running, I am going to make an overflow take out of PVC pipe and mount it to the radiator core support. There was a thread on here about it but I can't seem to find it.

The easy way is to find a old Monte Carlo are seemlier and remove it's over flow tank. They are cheap and they are GM parts to boot.