[Silver Streek]

When you change the thermostat always change both thermostat, if you are getting slow warm up times it's generally due to bad stats. I know you have recently changed the main stat, but you do occasionally buy a bad one that fails straight out of the box or soon after.

My advice is don't use the dealers they can be lazy and expensive working on older cars. Find a good independent, or better yet change the stats yourself, it's pretty straightforward. I always do mine myself on my M57 diesel.

It should be running up to temp and staying around 87 to 90 degs. Mine runs a pretty constant 87 to 88 degs. Any lower and your stats aren't working properly.

Low temps really affect your fuel consumption on diesels, eventually affecting your DPF too. The DPF needs an coolant to of 75C minimum to regenerate.