cooling system question

[smithy010]

Ok, so my diesel is working nicely now.

It has been pretty cold here at nights, (getting down to about7 degrees). When i went for a drive tonight (about 80km), the temp gauge did not go above about 1/4 or less up the gauge. When i stopped, the top rad hose was fairly warm, and the bottom hose was cooler, meaning the thermostat was still shut. As a result i am led to believe that the engine wasn't heating up enough to even open the thermostat...

Should i be concerned that the engine is running too cool?

[brackie]

Just a cold day?

Ok, so my diesel is working nicely now.

It has been pretty cold here at nights, (getting down to about7 degrees).

Ha!!!! You call that cold?? It was -7 here yesterday morning (and my mk1 still started )

When i went for a drive tonight (about 80km), the temp gauge did not go above about 1/4 or less up the gauge. When i stopped, the top rad hose was fairly warm, and the bottom hose was cooler, meaning the thermostat was still shut. As a result i am led to believe that the engine wasn't heating up enough to even open the thermostat...

That puzzles me. It's OK for the engine to stay cool in cold weather, but you should have had both hoses at least warm. I suspect the thermostat's jammed open. Replace it and see what happens.

Should i be concerned that the engine is running too cool?

Yes. Definitely. An engine not running at optimum temperature wears quickly (you wouldn't believe how much quicker n, sludges up and uses a lot more fuel. That's why we have thermostats

[Edison]

Ok, so my diesel is working nicely now.
Should i be concerned that the engine is running too cool?

not too much, but it works better when it's warm, in cold weather it's good to get a bit of cardboard box (or anything more elegant) and slip it in front of part of the radiator to keep it warm. I do it normally when going over the blue mountains 0-10degrees C it makes the heater work properly to keep you warm and means the combustion works more efficiently. it mentions exactly this sort of thing in the official manual supplied with the car, but calls it a car part from the dealer i think.