The V8 Owners Forum -

3.5 V8 in a Westfield kit.
Car has always run on the hot side but never overheated, has a Westfield supplied Ally rad.
Stationary when the fan cuts in it has a job bringing the temp down and from memory won’t stop until your on the move again.
It’s piped as below but I’m not sure this is correct, I don’t run a heater in the car.
I’m using an offy manifold and it’s has the water connnection at the back as shown, I can’t help thinking the water isn’t circulating through the rad correctly.
Maybe just blanking this connection is all it needs?
Thanks in advance.

Hi

I would suggest a restrict or between the manifold and Y piece.

Not a blank but perhaps 1.5 mm hole to allow it to bleed air bubbles

This in turn would mean the coolant is forced to flow through the radiator and not have an alternative route.


If you have a hose On this part of the circuit perhaps try clamping it with mole grips to test the theory before making big changes.

Ian

I do have a valve suitable for this I could close down to almost nothing.

Think if you do that you’ll have little or no circulation thermostat is closed.

I had presumed the thermostat had the hole drilled to allow some flow until the thermostat started to,open

I was under the impression that’s what the bypass hose was for?

That is a bit of an odd arrangement!

Water is sucked into the water pump from the bottom hose, the thermostat bypass hose and the long hose running from the 'Y' connector. It is pumped into the block backwards, and rises into the heads at the back of the engine. Then it travels forwards and comes into the inlet manifold at the front. From there, it goes either back through the inlet manifold and out to the 'Y' piece, out of the thermostat bypass hose, or out through the thermostat into the top of the radiator.

Depending on the radiator design, it is using all of the core? Is there anything to stop the water predominantly dropping down just the side of the core that the two hoses are in?, and never using the whole width?

My money would be to feed the header tank into the bottom hose. Then I would blank the thermostat bypass at the front (both ends), and just use a long hose from the rear of the manifold back around to the water pump as the bypass hose.

As it stands, you have two thermostat bypass circuits.

How big is the radiator? The one in my Landie is about the size of the 17" fan, and does not get anywhere near overheating.

Chris.

Attached is a simple version on a GT40 something similar work well!

Ian

Can you post a couple of actual pics of the plumbing in your engine bay. Looks a strange arrangement on the front of your diagram.

Engine is currently out of the car so no pics available, its piped as per the diagram really so im not sure how i can make it any clearer?

On your diagram you have three pipes connecting into to the pump. 2x small and 1x large.
One is a heater return (You don't need this so blank it off)
One is a thermostat bypass hose from the inlet manifold (The small pipe - you need this)
One large one is from the radiator bottom hose (you obviously need this)

The port at the back of the inlet manifold (where you have the Y adapter) would be your heater inlet (you don't need this so blank if off)
The hose from the bottom of your header tank should tee into your large bottom hose from the radiator.
The header tank needs to be the highest point in the cooling system.

Thats great, thank you.
Is there any reason i cant leave the hose on the bottom of the header tank connected to the heater return on the pump as the inlet is right next to the rad bottom hose inlet?
Im guessing it will perform the same function.

You don't really want much coolant flow through the header tank - so plumbing it directly to the pump (suction) inlet I don't think would be ideal as the pump will be constantly sucking on the header tank. you want as much of your flow (only) through the radiator as possible.
The header tank really only has two jobs, to allow the coolant an air space to expand when it gets hot, and as a high point in the system to collect any air.
Plumbing it into the bottom hose via a long small ID pipe will limit the flow through the tank, whilst enabling the tank volume to change with pressure variations.

Would be easy to try just removing/blanking the Y piece from the back of the manifold and trying it. If it works; great, probably benefit from a restrictor. If still marginal then look at moving the header tank feed pipe into the bottom hose.