Coolant system - expansion tank/bottle

[lambostylus]

Back to billy-basic questions... (mostly because I have a shocking memory, but also because have spent so long away from the build I can't recall the information!)

1. On past experience, can anyone advise whether an expansion tank is merely a good idea or absolute essential?
And if essential, is it sufficient to simply connect this into the system by a single hose or is this asking for trouble regarding creating potential vacuum pockets in the expansion tank.
(I have an old golf expansion tank ready to go, but I can't place it significantly higher than any other point in the coolant system, so am not entirely sure what to do with it.)

2. I can't seem to get the rad hot enough to trigger the thermostat (and fan). having boiled the darn thermostat on a stove with thermometer, it seems to work. What temp is best for it to switch at, if placed in the radiator rather than next to the block?

I'm also going to wire in a manual switch for those hot sunny days when my confidence might be failing!

as always, advice gratefully received.

[stylussprinter]

I think you said it was a 1.8lt Zetec and they like to run and are most efficient at 92 degrees. If you are using the original FORD thermo holder then you need the large exit pipe to the top of the radiator . The large water pump entry to the bottom of the radiator (this must have 3 seperate joins into it -- one from the expansion tank -- another from the thermo -- plus the return from the heater) Don't put any of these into any ' Y ' peice before joining Finally the tiny pipe from the thermo into the top of the expansion tank.
This is Paul Dunnell's water flow system for any Zetec --- the key to it's success is using 3 seperate joins into that bottom pipe about 50mm apart. I made an alloy 1.25 inch diam' x 10 inch long pipe with two joins into the bottom and one into the top .(needs a little hump sweated around the edge of each end to secure the hoses )

I wouldn't run without the tank Fit the tank on the bulkhead so that the cap is just clear of your bonnet when you shut it --- that's high enough then run the engine with the rear end of the car jacked up on stands , without the cap on the tank for 40 mins , topping up as it bubbles air out so's to avoid more air trapped ) ---This ensures it's the highest water point

The only other way is to use a RACELINE water rail as I do but it's more money Dunnell's system works fine but not if you mess around trying to save making a 3 way joiner by using ' Y ' peices further up