coolant pump: pressure control

[dark_knight]

just had an interesting thought.. i know the alternator has a voltage protection circuit/system that prevents it from churning out more than 14.4 VDC or thereabout.. and the oil pump has a pressure relief valve that prevents oil pressure building up too high when the engine revs go higher-than-normal.

now, just wondering if the coolant pump also has some sort of pressure control, or the cooling circuit needs not any kind of pressure control..? can anyone shed some light on this..?

 

[Rob H]

The rad cap is the pressure controal for the cooling system that's all there is as the thermostat only controls the flow till the engine gets up to temp.

 

[Jay]

It's built into the radiator cap. Excess pressure will exit into the reservoir under normal circumstances. In the case of overheating your headgasket is designed to blow before catastrophic damage is done ot the head and block.

 

[duratec7s]

you can sack of standard pump and put in electric water pump which can have flow control dependant on engine temp etc.....
bit overkill for a starlet though really.....

 

[dark_knight]

gunning a cold engine = blown cooling circuit?

so it's just as bad with coolant as it is with oil to gun the engine when cold because before optimum temp, the thermostat will be shut, meaning no way for the pressure release to get to the rad cap as this circuit is still shut off by the thermostat, correct..?

 

[weeJohn]

No, there is a small hole in the thermo housing that bypasses the stat for this reason.

 

[dark_knight]

is the bypass enough to keep the system safe when red-lining from a cold-start..?

 

[Texx]

The hole in the thermostat prevents air locks in the cooling system, it allows any air in the system to bleed past the stat and flow straight to the header tank of the radiator.

The thermostat controls the flow of coolant through the radiator, even when the thermostat is closed the radiator can still be pressurised through the bottom hose and so the cap can still pop.

 

[dark_knight]

rad pressurization

Texx, you bring a good point about the bottom rad hose. totally didn't think of that. oh well, this is nice to know..