2007-11-17 10:12:13 · 7 answers · asked by timmy t 1 in Cars & Transportation ➔ Maintenance & Repairs
The radiator cap only opens under pressure
2007-11-17 10:35:08 · update #1
The cap also has a vacuum relief valve that pulls the coolant back from the reservoir as engine cools
2007-11-17 11:10:25 · answer #1 · answered by tronary 7 · 0⤊ 0⤋
Mark H is right when coolant is hot it expands creating pressure. Your radiator cap only holds a certain pressure. when coolant excedes this pressure it passes the cap and goes into the over flow tank. as the coolant cools (when engine is off) the pressure starts to go down causing a vacuum thus sucking the coolant back inti the radiator.
2007-11-17 22:08:06 · answer #2 · answered by kellyglockman 1 · 0⤊ 0⤋
Thermal expansion, the fluid contracts as it cools causing a vaccum to build up in the closed system. The hose from the cap to the reservoir draws coolant.
2007-11-17 18:26:23 · answer #3 · answered by ThisJustin 5 · 1⤊ 0⤋
The coolant in the radiator cools and contracts which creates a vacuum and it is sucked out of the reservoir.
(After you shut the engine off, normally.)
2007-11-17 18:15:19 · answer #4 · answered by 19G30 5 · 2⤊ 1⤋
The cooling system operates under pressure. When the engine block is low the rad cap opens to let in coolant required.
2007-11-17 18:16:53 · answer #5 · answered by seed2ofchuck 2 · 0⤊ 3⤋
Thru the reservoir line
2007-11-17 18:16:31 · answer #6 · answered by maryann p 3 · 1⤊ 1⤋
By a hose connected to it along with the pressure it has built up helps it get back to there---if it didn't your radiator or radiator hose would burst!
:)
2007-11-17 18:17:07 · answer #7 · answered by fstladylaudie 4 · 0⤊ 3⤋