Thanks for the reply.

I did look at the thermostat and as I expected it is in perfect working order (did a pot test). When I was changing the thermostat last time I had lost one of the screws and could not find it. It turns out that it went in to the thermostat opening and did not allow the thermostat to close. I am so lucky that it did not get sucked in to the water pump. All is working well know. The car warms up in about 15 minutes at 17 F.

Question : What is regeneration switch over valve and what does it do?

It is loud enough that I can hear it on the drivers side with the hood closed. Is that normal?

Thanks