M42 radiator overflow coolant routing question

[Jim Lepage]

Here's my setup:

-aluminum water pipe to lower heater core

-metal water pipe to upper heater core

-upper radiator to left water pump

-lower radiator to right water pump

Where should I plug the overflow hose ? I capped the metal hose coming from the right water pump side behind the pulley thinking it was useless for my setup but I'm now wondering if I should plug the overflow there ?

I thought about routing it directly to the lower radiator output. Would it work ?

[butters]

Where should I plug the overflow hose ? I capped the metal hose coming from the right water pump side behind the pulley thinking it was useless for my setup but I'm now wondering if I should plug the overflow there ?

This is correct, that metal hose is for the overflow.

[Jim Lepage]

This is correct, that metal hose is for the overflow.

Yeah I know but I think I'll let it shut and route the overflow to the radiator output pipe.

[butters]

Yeah I know but I think I'll let it shut and route the overflow to the radiator output pipe.

I won't claim to be an expert, I can't say for sure, but it seems like that would be a relatively significant change in the plumbing. The metal expansion tank pipe that runs from the water pump is on the engine side of the thermostat, i.e. coolant can "expand" through that path to the tank before the thermostat opens. You're looking at plumbing the water pump right to the hot side of the radiator?

You might look into the Z3 version of the S54 plumbing, which has the expansion tank plumbing on the driver's side of the car iirc.