I seem to have plumbed my cooling system wrong as have to have heater on. I have mg v8 radiator, Offenhauser manifold with by pass inlet in thermostat housing, Harrison header tank, spitfire radiator.
Does anyone have a diagram of how it should be plumbed. There seem to be many variations on the Internet. Am I right in thinking all water pump outlets are feeds into the pump?
Thanks
Radiator flows
Re: Radiator flows
Hi Tony,
I can only relate to the Rover set up which as you have mentioned a MGV8 rad I assume you have.
The two small and one large connection on the pump are indeed inlets and should therefore be the cooler water going in.
Main cold flow from radiator bottom goes to the large pump inlet and into the block. The heater bottom outlet connection travels under the inlet manifold and dog legs across and bends into the small vertical connection on the pump.
There is also a separate by pass connection from the thermostat housing going into the small connection on the back of the pump.
The heater top inlet comes from the rear of the inlet manifold. The large hot water outlet from the thermostat housing goes via the Harrison tank to the top of the radiator.
I have made mine a closed system by adding an overflow tank ( Austin Metro) and so the overflow pipe from Gerry's header tank has clips to make it pressure tight and it goes into the bottom of the over flow tank. The header tank has a simple cap ( not pressure relieving) and the pressure cap is put onto the overflow tank. Thus when the engine gets hot the water expands and goes into the overflow tank and when it cools down it sucks it back in rather than having dumped it onto the road.
The only issue I have had is the delayed reaction of the thermostat compared to the temperature gauge. The hot water seen by the temperature probe has to travel to the end of the manifold and back again before getting to the thermostat housing.
Hope that helps.
Peter C
I can only relate to the Rover set up which as you have mentioned a MGV8 rad I assume you have.
The two small and one large connection on the pump are indeed inlets and should therefore be the cooler water going in.
Main cold flow from radiator bottom goes to the large pump inlet and into the block. The heater bottom outlet connection travels under the inlet manifold and dog legs across and bends into the small vertical connection on the pump.
There is also a separate by pass connection from the thermostat housing going into the small connection on the back of the pump.
The heater top inlet comes from the rear of the inlet manifold. The large hot water outlet from the thermostat housing goes via the Harrison tank to the top of the radiator.
I have made mine a closed system by adding an overflow tank ( Austin Metro) and so the overflow pipe from Gerry's header tank has clips to make it pressure tight and it goes into the bottom of the over flow tank. The header tank has a simple cap ( not pressure relieving) and the pressure cap is put onto the overflow tank. Thus when the engine gets hot the water expands and goes into the overflow tank and when it cools down it sucks it back in rather than having dumped it onto the road.
The only issue I have had is the delayed reaction of the thermostat compared to the temperature gauge. The hot water seen by the temperature probe has to travel to the end of the manifold and back again before getting to the thermostat housing.
Hope that helps.
Peter C
Re: Radiator flows
Thanks Peter I opened the vent in the inlet manifold and it was empty, I think my problem is the pipe going from radiator to thermostat. It doesn't open to the harrison tank, the tank is connected via a tee to the heater return into the pump. I plan on working on it today. Let you know if I solve it.
Cheers
Cheers
Re: Radiator flows
Tony,
Looking at photos of original cars the genuine Harrison tank as apposed to Gerry's version were only connected by a small dia pipes as apposed to the main flow to/from the rad. Some show two pipes others only one. As the tank is mounted higher than the rad there is a vent pipe from the very top of the rad into the Harrison. The heater hose sized pipe does seem to go down towards the water pump but I expect T 's into the heater hose.
I guess over the years it was piped up several different ways.
Peter C
Looking at photos of original cars the genuine Harrison tank as apposed to Gerry's version were only connected by a small dia pipes as apposed to the main flow to/from the rad. Some show two pipes others only one. As the tank is mounted higher than the rad there is a vent pipe from the very top of the rad into the Harrison. The heater hose sized pipe does seem to go down towards the water pump but I expect T 's into the heater hose.
I guess over the years it was piped up several different ways.
Peter C
Re: Radiator flows
Hi Peter
Turned out to be a faulty thermostat. Took it out and even with my tidy but perhaps incorrect plumbing all seems well. May take it to a garage to tune as the mallory vacuum seems too much have blocked off for now.
Are you out local to West Sussex?
Cheers
Tony
Turned out to be a faulty thermostat. Took it out and even with my tidy but perhaps incorrect plumbing all seems well. May take it to a garage to tune as the mallory vacuum seems too much have blocked off for now.
Are you out local to West Sussex?
Cheers
Tony