cold level in the coolant reservoir?

[kikkegek]

i changed my rad to an aluminum version and took a good look at my total cooling system.

I dont understand why there is a cold level in the coolant reservoir?

isnt the only function of the reservoir "overflow"? so excessive coolant can flow freely at too high pressure in the rad?

or does the coolant also get sucked back in?

here is a old pic of my coolant tank, clearly showing the cool level.

[tucsonjwt]

Theoretically, I have read that the radiator should "put and take" from the reservoir as needed. I fill the reservoir to the cold level but I notice that the level drops a bit after a while - I think that the loose fitting fill cap allows for some evaporation.

[TheApocalyptican]

I was always under the impression that it did indeed pull from the tank and into the radiator, as well as expand out of the rad to the tank.

[kikkegek]

hmmm...okay, I thought it only spilled into the tank at overpressure, but I'll watch it the next couple of days and see if the level changes...thanks guys...

[fastwillie 696969]

Originally Posted by tucsonjwt

Theoretically, I have read that the radiator should "put and take" from the reservoir as needed. I fill the reservoir to the cold level but I notice that the level drops a bit after a while - I think that the loose fitting fill cap allows for some evaporation.

some will naturally evap as coolant loses its ph level and its strength, water will dissipate which will lower the level

[Keith Seymore]

Originally Posted by TheApocalyptican

I was always under the impression that it did indeed pull from the tank and into the radiator, as well as expand out of the rad to the tank.

Absolutely. Well spoken, sir.

The "cool level" line is what allows you to set the proper fluid level, so that you can do it at your convenience (when the engine is cold) rather than after everything is heated up under there (like when checking automatic transmission fluid - which is a pain).

K

[78 Chevyrado]

The tank keeps the pressurized part of the system full. It also keeps from dumping coolant on the road.

Before they had coolant tanks, if you filled your radiator up full and went driving, when it got hot it would push coolant out and onto the road. Then when the radiator cooled down completely if you opened the radiator cap, it would be like an inch or so below full.

Anytime you get it up to operating temperature, coolant comes out of the radiator and goes into the tank, and any time it cools down completely it sucks coolant back into the radiator. tanks an easy way to tell if you have enough coolant without touching or opening anything.

[kikkegek]

alrighty tighty guys! thanks very much, that clears things up!

[masterjohnson]

Originally Posted by 78 Chevyrado

The tank keeps the pressurized part of the system full. It also keeps from dumping coolant on the road.

Before they had coolant tanks, if you filled your radiator up full and went driving, when it got hot it would push coolant out and onto the road. Then when the radiator cooled down completely if you opened the radiator cap, it would be like an inch or so below full.

Anytime you get it up to operating temperature, coolant comes out of the radiator and goes into the tank, and any time it cools down completely it sucks coolant back into the radiator. tanks an easy way to tell if you have enough coolant without touching or opening anything.

i think i am now enlightened.lol i thought i am having leaks on my radiator or in my coolant think so i place something beneath my truck then the following morning there is no sign of any leaks and i just figured out maybe i just need to change my rad cap and it worked for me. my cap is an after market before then i switched again to stock rad caps. lesson learned: if you use stock parts you wont be having any problems at all.lol

[Axle]

The hip new term is 'coolant recovery system'.