The V8 Owners Forum -

On the Vitesse unit, there is a steel pipe (ERC9123) which screws into the inlet manifold at the front and runs underneath it to the heater. Being steel, it eventually rusts through and is NLA. I made a new one using domestic plumbing bits - but it's leaking again. My guess is the brass bush I used has the same TPI as the original but not the same thread profile, so despite lots of PTFE tape eventually starts weeping. The face on the inlet manifold it mates to isn't square to the thread, so you can't use a washer between it and the pipe bush.

Later versions of this engine - like say the 3.9 - don't use this pipe. Where do they get the heater feed from?

You have to remove the inlet manifold to get at this pipe so not ideal.

Heater feed on my 4.6 comes out of the inlet manifold, threaded hole to pipe.



Tom.

I thought the heater feed was on the back of the manifold ?
Your pipe was heater return!
Please correct me if I'm wrong ?

No, the heater feed is on the front left of the manifold.
The heater return feeds into the bottom hose/thermostat housing/pump inlet.

Tom.

You're confusing me.

The pipe I'm talking about comes from the same 'chamber' that contains the thermostat. On the other side of that to the top hose.

Sorry if I'm getting flow and return confused.

I've seen manifolds with this tapping fitted with a blank plug - so there must be an alternative way of doing it.

I have a 4 litre manifold here which is a different casting - and that does have the heater as shown in the pic. However, I'm not sure that could be used with my 3.5 Vitesse unit.

I confuse my self quite often

The long pipe which has rusted for you is the heater feed, the return goes parallel to that and feeds the back of the water pump, well it did on my 3.5 flapper engine.

If you don't have a heater you can block off the port that this pipe screws into as long as you have the bypass circuit connected.

You could use the bypass outlet to feed the heater, but if that would then be replace your bypass circuit then there shouldn't be a heater valve to cut off that flow. I guess you could use the bypass outlet to feed both the heater and the bypass circuit but with the higher resistance of the heater matrix I don't know how much hot air you'd get in the cabin.

I think the main difference with the older manifold is the injector holes, the newer manifolds designed to take an o-ringed injector. Also there is a flat for the idle control valve to bolt to which is not on the newer manifolds. If you can get the injectors to fit, and have some sort of idle control then I don't see any reason you can't use the newer manifold. You'd need to check regarding to holes/threads for the sensors.

Tom.

As I said, I've got a manifold here (among the many) - same as the one on my SD1 - with a blanking plug where the pipe goes - and surely every vehicle has a factory fit heater? So I was guessing there is an alternative factory way of doing things to this pipe?