Temperature Oddness

[AdeV]

All through summer (indeed, any time the outside temperature is above about 12 degrees), my Mk2 LS400's temperature behaves perfectly - straight to 1/2 way & stays there, solid as a rock.

As soon as the outside temperature dips below 10-12, the temperature gauge stops coming up to half way & hovers anywhere between the 1st mark (if it's really cold) & just under 1/2 way. I've never noticed it affect the cabin temperature. I don't believe it's a t-stat fault, as the car warms up (starts blowing hot air) after about the same time no matter what the outside temperature. Yesterday, I noticed a slight dip in the cabin air temperature at one point, which is a new symptom, but that may just be a low water level (my top hose occasionally leaks).

The car did the same thing for the last 2 winters, but not the 1st winter I owned it.

Any ideas?

[AdeV]

Bump...

Has no-one got any thoughts? Should I repost in the Engine subforum perhaps?

[ROYT]

Bump...

Has no-one got any thoughts? Should I repost in the Engine subforum perhaps?

For my two pennorth, the thermostat is my prime suspect...