Hello Gentlemans,

i am Benno from Germany and life in Dubai, i drive a Chevrolet Blazer 1996 4,3l 4WD.

No my Problem, in the engine room there is a radiator and a coolant recovery tank.

My recovery tank is every time full, it never goes low. My radiator lost per week coolant, round 1 liter. But i didnt have a leak, there are no oil in the radiator and no coolant in the oil system.

If i drive the temperature is ok, if i stop it goes up because the coolant missing. If i push the throttle i can pull down the temperature.

Iam sure if i arrived my goal in the city an stop the car, the temperature of coolant will goes up and reach more then 100 degrees. Now the coolant will goes over the springvalve in the cap, back in the coolant recovery tank.
Thats normal!?

On coolant recovery tank there fixed to hoses, one is going from the cap of radiator to the bottom of the tank and one is fixed on the top and this end is hanging arround in the engine, i think thats for overfill/full.

How comes the coolant back in the radiator?

Because there is only one hose, he is fixed direct on the neck of the cap thread and in front there is the one way valve with a spring. If i understand this construction right, the coolant liquid can got from the radiator to the recovery tank but not back?

Wahts that for a construction? Is it the same in your blazer´s? I didnt understand the system. Or is my Cap wrong? Did you have a spring valve in your radiator cap?

Thank you guy for your help!

 

When the engine cools down the radiator will suck coolant back into the system from the overflow. If you are losing coolant, check for a leak possibly at the water pump or an intake leak at the back of the engine. With a small or slow leak, you will not see coolant dripping because it evaporates off of the hot engine before it hits the ground.
A leak could cause air to be sucked into the system from the atmosphere instead of from the overflow tank.

 

Thx bandidolenny, i was few days before in a workshop and they measure with over pressure the radiator and the radiator/system doenst los air by this measure.

can you explain how the coolant can go back from the overflow?

I think my cap is the problem becaus it close the way from overflow to radiator.(valve inside with a spring)

 

The radiator cap maintains the cooling system at 15-16psi at all times. As the coolant heats up, it expands. Once it expands enough to reach 15-16psi, any further expansion pushes past the radiator cap and into the overflow bottle.

The cap also has a check valve in it. This check valve is sealed when the system is under positive pressure. Once the system starts to cool, the coolant in the cooling system shrinks back down causing the system pressure to decrease. Once it has decreased enough for the pressure to reach zero, the check valve will open. Further shrinking of the fluid will result in fluid being pulled back into the cooling system from the overflow bottle.

If there are any leaks in the system, this return flow from the overflow bottle to the cooling system will likely not take place.