Thread: can i pick someone's brain please

I think we need a little more clarification here.
I don't think I have your answer but I think you're asking to identify which pipe is the inlet, which is the outlet on the motor, and which is the inlet, which is the outlet on the heater (where it come through the firewall)?
Not even sure if it matters? There would still be flow through the heater when it's on, no matter if the tap for water flow is on the outlet or inlet pipe? Only prob might occurr if the heater matrix was clogged in one direction, an you run it the other way and the muck goes into your cooling system. I'd flush it first in both directions and check it's not leaking before conecting it up.

Originally Posted by davros

I think we need a little more clarification here.
I don't think I have your answer but I think you're asking to identify which pipe is the inlet, which is the outlet on the motor, and which is the inlet, which is the outlet on the heater (where it come through the firewall)?
Not even sure if it matters? There would still be flow through the heater when it's on, no matter if the tap for water flow is on the outlet or inlet pipe? Only prob might occurr if the heater matrix was clogged in one direction, an you run it the other way and the muck goes into your cooling system. I'd flush it first in both directions and check it's not leaking before conecting it up.

It does matter as the heater core is an upright and filling the heater from the top tank causes airlocks.

A 3.9 has two pipes running down the drivers side of the intake manifold.
The supply from the engine comes from under the manifold just near the thermostat and connects to the pipe with the riser on it with the plug.
The hose to the firewall connects to the pipe on the drivers side.

The heater return pipe then goes to the other steel tube without the fill riser and connects on to the back of the waterpump housing.

You need to remove the plug in the radiator, fill it from the heater pipe to top it up, put plug back in pipe and radiator, run the engine and just crack the filler plug seal with it running to purge any air in the heater circuit.

These suffer badly from airlocks so an occasional crack of the expansion bottle cap for a day or two to release any trapped air with the engine running tends to help. Just make sure you check the level in the bottle everytime and top up as needed.

Regards

Andrew