2F Thermostat housing and fan switch

[al_kaholik]

Should there be a gasket between the block and the stat housing? There was none in it previously, but after changing the thermostat and removing the housing to do it - some bell removed the captives and put screws in instead - there is a leak from the top mounting bolt, this is even after replacing the o-ring and bolts.

Also my fan does not come on when the engine, assuming the gauge reads correctly, reaches over 90 degrees. The coolant pipes are far too hot to hold more than a second or two, so I am thinking that the temperature is correct. Do I assume that the switch is at fault?

I'm new to the water cooled scene, gimme an aircooled any day after all this trouble! If it helps the car is an H reg 1 litre injection.

Thanks in advance.
Al