OK, got a V-reg Ford Focus 1.6 Petrol Zetec Engine.

had to replace the thermostat housing on my car the other week as it had a crack in it and was leaking. Got new seals and replaced the thermostat at the same time.

However, I don't think the new thermostat is working. The hose going from the stat to the bottom of the radiator is always cold, whereas all the other hoses are hot. The cooling fans will start running, even though there doesn't appear to be anything flowing through the radiator and theres water bubbling back into the expansion tank from the hose that goes from the top of the engine block .

The odd thing is though, the gauge on the dashboard shows the temperature as "normal"?

When I first refilled it, I had assumed it was just an airlock. I had to replace the stat a few years back and found that by releasing the cap slowly after it had reached temperature released the air and the cooling system worked fine after that. However, this time, having done this several times now, the problem is persisting.

So, any suggestions as to what else might be causing this before I start stripping the engine down again to test the stat? I would have thought being brand new this wouldn't have happened, but can't think of what else it might be and the thermostat housing is a right swine to get to, being sandwiched between the alternator and air-con pump.

Also, any ideas why the gauge on the dash still says the temp is "normal" when the radiator cooling fans are going full belt?

Thanks in advance.