Thermostat Question
 

I have a question about the thermostat on these engines. I drive to work and around town.. the temp is always in the middle but the lower radiator hose is always cold to the touch even after a run? Does it take a lot of hard driving to get these up to temp?

With a thermostat that didn't open, I could operate freely at less than one third throttle and not overheat.

More than many other diesels, certainly much more than a gasser.

Describe your driving mode, and ambient temps.

Is the radiator as cold as the lower (return) hose? Is the rad temp consistent top to bottom, side to side?

I drive about 15 miles to work one way. I do drive easy for best mileage and the temps here are pretty cold right now. I would say 30 to maybe a high of 45 F

If I just start up an leave, I'm up to operating temp by the time I reach the highway 2.5 miles away.

Same here, In my case it`s appr 2miles usually taking 5-8mins driving, depending on traffic but very light driving, several redlights, Winter cond.
Idk if it makes a diff but heat/blower is definitely off (it`s often 14-20F (-5,-10C) now in the mornings)
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``the temp is always in the middle but the lower radiator hose is always cold to the touch``

My lower hose is always somewhat (or more) `colder` than the upper one, even after driving an hour at 65mph.
A digital (non-contact) thermometer is your friend there

Hot water in on the top and cold out the bottom. I assume that is the coolant
Flow. I would say the radiator is just getting the coolant close to ambient
Tempature

If a t-stat is stuck open the motor usually won't warm up at all do to the coolant
Always flowing

Yep, hot out of motor at upper hose, cold in at thermostat housing (lower hose). If the lower hose stays cool in cold weather driving with light load on the motor, means the t-stat and rad are working as they should. If t-stat is stuck open, you'll feel more heat in the right side of the rad and in the lower rad hose.

87`c
 

http://www.eeuroparts.com/Parts/5459...7-Deg-411687D/

Is this the right one for the turbodiesel Volvos (740)?
Thank you.