Re: what courses bad MPG on JTD
Coolant temperatures have been steadily increased over the last twenty years. The 164 had an 'upgrade' stat quite early in its life taking it from 92 to 97c I think.
There is only one reason, and that is emissions. The quicker you can get the engine up to a high temperature the quicker you get to conditions for complete combustion..or as near as you can call it complete. High temps get the catalyst working quicker, and in cooler climates there is a better chance of keeping the cat hot and working.
We had a new stat in the 2.4JTD recently. In fact I think I have put one in just about every Alfa i've ever had. Stats are not Alfas finest hour..and yes the one for my V6 cost £21..and the one for the 2.4 was £70 plus......ouch indeed!!
If your engine is slouching around at 70C it may well be cool in one sense, but not in another. It needs replacing. It should be on 90.