Radiator pressure 1988 740 Estate

As the water pump pressurises the cooling system based on the revs of the
engine the higher the revs the more the water pump pumps the higher the
radiator pressure I assume.

If this is correct then if the engine is a high revs then the rad pressure
will be higher but by home much in relation to idle.

If my assumption is correct then after the engine returns to idle how long
before the pressure drops.


?

 

The water pump is designed only to circulate the water, it doesn't create a
pressure. The pressure in the cooling system comes from the water increasing
in temprature, but when the pressure exceeds approx. 15 PSI, a valve in the
radiator cap opens and lets the pressure out.

(Sorry about the language, i'm a swede).
/Erik

 

Nothing wrong with the language, the english looks as good as my (native)
english.

 

Is the enclosed reply correct, if the engine revs higher the water pump will
pump more water as the pump is connected to the
engine pulley.

As the water pump has a large hose and other parts of the water system are a
smaller diameter then there must be pressure as a result although the
pressure may not be great.

If I rev the engine I get a gurgle sound in the heater matrix, if I close
the heater valve and stop the flow of water to the matrix the gurgle stops.

Open the valve rev the engine I get the gurgle, this would indicate to me I
have a slight block in the heater matrix which would cause a build up of
pressure in the cooling system.

 

Not only was the English flawless, so was the advice. There's only one
thing that normally adds pressure to the cooling system - engine heating
of the water. The pump does not add any pressure. If pressure is
getting in another way, it's probably from the head gasket or a
cracked/corroded cylinder head. Also air should burp out of the cooling
system on its own - if air is continually getting into the system that's
another indication of a head gasket problem.

--
Mike F.
Thornhill (near Toronto), Ont.

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