Now this may be common knowledge and I have a vague memory of discussing this with some one at some stage. When I got the thermostat out of the packet I gave it a good inspection to make sure it was the same diameter and height as the old one and all this checked out. The only difference I could see between the unit I pulled out of the car and the new one was that the one in the car had a tiny little cut out in the seat of the thermostat and the replacement model had a hole in the flat disc section with a little loosely fitted brass pin in it.
Now I assumed that the little indent and the hole with the brass pin in it would serve the same purpose of allowing water through before the thermostat before it opened but I was wrong. After installing the new thermostat I took the car for a quick blast to the end of the street and back and then popped the bonnet. As I lifted the bonnet I saw that water was coming out of the rad over flow which I thought may have just been a knackered cap, but after feeling the hoses and having a closer look I was not getting any flow past the thermostat. After thinking about it for a little while I whipped the thermostat out and cut the little pin out reassembled and refilled with water and bobs your Uncle she was a goer.
Has any body else ever come across this or know any thing about it???
