[thopwood4]

Still in break-in period, around 550 miles or so right now, so trying to vary speeds and rpms while driving. I try to keep it around 72 or so on the highway but will accelerate gently to a higher rev range and cruise at 85 for a bit or so. When I do those shorter squirts of acceleration I notice my water temp drop dramatically. I've never seen this in a car before. My E90 has the MPerformance wheel with water and oil temps on the top of the wheel and that car never did that. Granted there is a much smaller grille opening. Today was 18 degrees this morning so the drops went from the 210 mark down to 170 or so. I know there is an increase of airflow, and very cold air today. Just wondering if anyone else has seen this? I've also seen it around 50 mph too, so not necessarily highway speeds.

[forcefed]

That's normal.

[kgelfen360]

Mine does something similar and it’s 45 degrees outside.

[RUNSOK]

Same here.. I don't know why but I have never seen a car that fluctuates water temp during regular driving. Mine fluctuates between 160 to 190. Oil temp gets up to 200 and stays there which is normal.

[CDunster]

Totally normal. These cars have a great track ready cooling system. Mostly on cool days you'll notice the water temp drop quickly when you get on the throttle. The variance is not as noticeable on hotter days.

[SwankPeRFection]

You sure you’re looking at coolant temps and not oil temp. Jumps in quick acceleration like that and the temps you described are usually the jumps seen in oil temp.

[Bimmerfun82]

Great cooling system. I was also a bit surprised but totally normal esp in cold weather. This is water temp we’re talking about. Oil temps on the other hand are fairly consistent once warmed up. But even in hard driving I’ve seen oil temps drop slightly as well but no major variability.

[mdr955]

Originally Posted by SwankPeRFection

You sure you’re looking at coolant temps and not oil temp. Jumps in quick acceleration like that and the temps you described are usually the jumps seen in oil temp.

I’ve never seen my oil temps drop like that. Usually very stable around 210 or a drop higher once warmed up.

[christianb5s4]

This might be one of the few cars I've ever seen that have higher temps when cruising on the highway versus driving around town, even getting on it. To other's points, totally normal and thankful this car is so effective at cooling out of the box.

[SwankPeRFection]

Originally Posted by mdr955

I’ve never seen my oil temps drop like that. Usually very stable around 210 or a drop higher once warmed up.

If there’s a malfunction in the oil cooler temp control where it’s opening sooner than needed and closing later than needed, then yes, it could reach down to 170-180 of that cooler isn’t shut off quickly enough, especially if it’s cold outside when it’s doing it. If that bypass control isn’t working as it should, that oil cooler will drop temps quick in the winter.

[thopwood4]

Originally Posted by SwankPeRFection

You sure you’re looking at coolant temps and not oil temp. Jumps in quick acceleration like that and the temps you described are usually the jumps seen in oil temp.

Nope. Looking at coolant. Interesting the oil temp will drop too it sounds like? I’m putting a mishimoto oil cooler guard on, will that affect the cooling? I haven’t seen the oil temp drop, similar to my E90’s experience with water temp, I’ve never seen the oil temp drop on that. That one just goes higher. 🤣

[SwankPeRFection]

No, you’re good. Put it on.

[forcefed]

Originally Posted by thopwood4

Interesting the oil temp will drop too it sounds like?

Nope, the thermostat for oil is closed till 212f to get it upto temp, after that 50% gets routed to the oil cooler, after 240f all the oil goes through the oil cooler. Unless you're tracking the car i wouldn't worry about any oil cooler guard affecting temps.