Running engine temperature in cold weather

[aeroden]

Good day guys,

I noticed when it's 7-12C outside the engine temperature gets down to 65C when I'm cruising on a freeway at 100km/h. Is that normal?

It didn't go below 65 when it was both 12C and 7C so I would assume thermostat is shutting off radiator flow to the engine warm?

When it's idling, the fan keeps at around 100C. But on the other hand I would've expected thermostat to shut off the radiator when cruising in cold weather to keep the working temperatures close to 80-85 - to narrow engine operating temperature range (wrt metal parts expansion/contraction, etc.)

What's your experience?

[Antares]

Originally Posted by aeroden

Good day guys,

I noticed when it's 7-12C outside the engine temperature gets down to 65C when I'm cruising on a freeway at 100km/h. Is that normal?

It didn't go below 65 when it was both 12C and 7C so I would assume thermostat is shutting off radiator flow to the engine warm?

When it's idling, the fan keeps at around 100C. But on the other hand I would've expected thermostat to shut off the radiator when cruising in cold weather to keep the working temperatures close to 80-85 - to narrow engine operating temperature range (wrt metal parts expansion/contraction, etc.)

What's your experience?

65 sounds a little low, mine only gets down to like 75c even on cold winter days

[Salem]

Seen from another angle, this 165bhp bike can do 250kph. Very simple calc, just air resistance alone with no respect to mechanical & tire losses & electrical load & wet clutch cooling implies if you are cruising at 100kph you are using 100^2 / 250^2 or just 16% of its power. Also the reason why you get that great tank mileage at that cruising speed. A BMW 310 does that speed  easily, 1000cc is an overkill.

Thermostats have a weep hole to aid in getting air out. That gives a tiny coolant flow thru the radiator. As the flow is tiny, it gets cooled down  to (too cold) ambient. Just this, and the normal cold air flow might explain it. Radiator is not hot, so cold air hits both the exhaust pipes (not very hot either) and engine block. Might thus be simply too cold and too low of a load on the engine. 

Simple test would be trying to block the radiator off with carton or plastic  If you have a (BMW) radiator protection not too difficult with tie wraps. 65C coolant is too cold for efficient engine operation, you want 85 or so

You'd want the oils at 100 C+ plus so it can boil off any condensed water and blow the steam out thru the carter vent. Just my old school thinking

[Mareng1]

Originally Posted by Salem

Seen from another angle, this 165bhp bike can do 250kph. Very simple calc, just air resistance alone with no respect to mechanical & tire losses & electrical load & wet clutch cooling implies if you are cruising at 100kph you are using 100^2 / 250^2 or just 16% of its power. Also the reason why you get that great tank mileage at that cruising speed. A BMW 310 does that speed  easily, 1000cc is an overkill.

Thermostats have a weep hole to aid in getting air out. That gives a tiny coolant flow thru the radiator. As the flow is tiny, it gets cooled down  to (too cold) ambient. Just this, and the normal cold air flow might explain it. Radiator is not hot, so cold air hits both the exhaust pipes (not very hot either) and engine block. Might thus be simply too cold and too low of a load on the engine.

Simple test would be trying to block the radiator off with carton or plastic  If you have a (BMW) radiator protection not too difficult with tie wraps. 65C coolant is too cold for efficient engine operation, you want 85 or so

You'd want the oils at 100 C+ plus so it can boil off any condensed water and blow the steam out thru the carter vent. Just my old school thinking

What?  If there is entrained water in the oil, then it will boil off at 100c (not on the oil pump discharge side - as the pressure will elevate the evaporation temperature.   The last thing you want is that foaming oil in your sump.   

Oil should not have a bulk temperature of >100c.

That’s just my old-school thinking.

Back to the OP - I think that some further investigation, and possibly a new thermostatic valve.   They are cheap units, and DO jam.

[Salem]

(funny with a few answers and 100+ no comment views), i think I disagee with you. These people seem to agree with me. As you stated you can not boil of water on the pressure side. It needs to happen non pressurized in the sump. And that requires 100C+

edit error in link:

https://www.verus-engineering.com/blog/informative-8/oil-cooling-a-deeper-look-29

[smithy]

Originally Posted by Mareng1

Back to the OP - I think that some further investigation, and possibly a new thermostatic valve.   They are cheap units, and DO jam.

Difficult to get at though...

Smithy.

[aeroden]

Did some tests - to my understanding radiator should stay cold till engines goes to 80+C.

Well, my radiator heats up quicker than the engine  (started the engine was 22C cold): https://imgur.com/a/VxzFMjk

Is it highly probable that the the thermostat valve is stuck open?

[Mareng1]

If the coolant is being directed to the radiator from start up- I think it is safe to say that the TV is jammed open to it.

[aeroden]

Got the thermostat replaced eventually - did not help a bit. Still runs at 65C on 15C ambient day when cruising at 6th gear on freeway @100km/h.
The old thermostat works fine as well - closed when cold and opens up when I boil it.

The holes Salem mentions are not that small though - see the picture.

[aeroden]

Went for a ride with a friend who has 2018 model with only 9k odo on it and his was running similarly cool with +/-1C difference from mine. I guess these just run cold on the cruising speeds.

At least, thanks to Smithy I now got a non-abrasive coolant