Cooling pipework

The cooling turned out not to be too difficult in itself, once I had got my head around the connections which I needed to make, although the actual making of the connections proved to be harder than it needed to be. The key to working out the pipe runs was help from fellow builders Nick and Robin, and a diagram from Tom Wood’s blog which turned out to be just what I needed.

Cooling Schematic

Cooling Schematic

After fitting the radiator and the upper and lower radiator hoses, I began with the thin expansion bottle pipe, laying it roughly in place. The hose I had was considerably longer than needed, but I resisted the urge to cut and fit until I was sure I had the layout correct.

I fitted the pipes in this order – now cutting as I went as I concluded there wasn’t really any other option:

  • Expansion bottle to T-piece;
  • T-piece to engine;
  • T-piece to modine;
  • Modine to heater valve;
  • Heater valve to heater (inlet);
  • Heater (outlet) to heater valve;
  • Heater valve to submarine;
  • Submarine to water rail;
  • Engine to expansion bottle (that first pipe I put in place).

When fitting the submarine, there were a couple of choices to make. Fitting the temperature sensor (which is the reason for the submarine) is done via a screw thread. This is apparently prone to leaking, so I chose to use a few wraps of PTFE tape (thanks Simon) to try and make the thread watertight.

The second choice is how to route the pipes either side of the submarine. This is complicated by the loom wiring, which needs to connect to the sensor and also an earth for the submarine. I found the wires emerging from the loom to be pretty short, and therefore a big limitation on where the submarine could sit. The Guide indicates an “under” arrangement, where the submarine sits just above the bellhousing. I could not make this work with the loom wires, and also it seemed to be a difficult position to reach in the case of leaks from that sensor thread.

As a result I went for an “over” arrangement, helped along by Robin who has got a similar set-up through IVA recently. It makes much more sense to me: easier access plus no stretch on the wires. I also had no way to connect the earth on the submarine – Derek obliged with a ring connector via the post as shown in the photo above.

One thing I really struggled with in this part of the build, and I mean really struggled with was the hose clips provided. For the male connections on the modine and water rail, I could not make the provided clips open wide enough to fit over the register on the connector without them popping open in the process of fitting the pipe. I ended up shouting in frustration after spending a precious hour of build time fighting with clip after clip trying to connect up the modine.

I nipped out to ScrewFix and bought the next size up. The job was done in 5 minutes. Bah.

The last step in this process is to run the heater control from the driver footwell to the brass switch – a pull on it opens the tap to allow hot water from the system to flow through the heater, a push closes it. Lovely, simple engineering.