[ryanpat198808]

Hi everyone, whilst driving on the motorway at roughly 60mph for around 15 minutes I noticed the temperature gauge fall. The temperature falls from the usual temp near 120c (250) to above 90c. Is the normal for the b58 engine to drop temperature whilst driving at low revs for longer periods? Also my heating was on max too.

[Billfitz]

The temperature does vary with how you're driving. For the most part it runs hotter when cruising for higher efficiency, cooler when your speed varies to prevent pre-ignition when you accelerate. The temperature dropping while cruising is out of the norm.

[ryanpat198808]

Just wondering could be anything to do with it showing oil temperature instead of coolant temperature. I am quite confused on what the temperature gauge on my 340i shows as it has a oil/coolant symbol. If so would the oil temperature drop whilst cruising?

[HighlandPete]

Originally Posted by ryanpat198808

Just wondering could be anything to do with it showing oil temperature instead of coolant temperature. I am quite confused on what the temperature gauge on my 340i shows as it has a oil/coolant symbol. If so would the oil temperature drop whilst cruising?

Oil temperature is managed, like coolant temperature (ECT) is. Does seem odd that oil temperature is dropping so low. May be worth running the hidden menu, to see what the ECT is doing as well.

Just reread your original post, "heater on max..." not enough cabin heat? What ambient temperature?

[ryanpat198808]

I have attached an image of roughly where the needle goes when cruising. I usually have the heating on at 28c which is the highest setting.

[Billfitz]

That's pretty much where my needle sits most of the time. Why 28C/82F? Are you growing tomatoes in the back seat?

[JimKden]

You might have a problem with the computer controlled coolant temperature control ball valve. Thermostatic coolant control is not by a thermostat but is controlled by the 3 way ball valve. Coolant continuously heats/cools the oil to the oil warms quickly. Temperature gauge reads oil temperature. I oil gets overheated, either it's an oil problem or a coolant problem. Two types of issues are indicated by the single gauge by design.
See the training manuals on this site if you are interested in learning about how it works.

[Wgosma]

Originally Posted by HighlandPete

Oil temperature is managed, like coolant temperature (ECT) is. Does seem odd that oil temperature is dropping so low. May be worth running the hidden menu, to see what the ECT is doing as well.

Just reread your original post, "heater on max..." not enough cabin heat? What ambient temperature?

+1
Take a look at what the cooling water temp is doing, may give you a clue.

[ryanpat198808]

In terms of actual temperature the car usually runs at around 115c during city driving and then cruising it sometimes drops to 100c. Is this not normal for the b58 engine? I believe I had the temperature wrong in my first post. I assume the line between 120 and 70 is 95 therefore my car runs above 95 around 100c whilst cruising. I hope this makes sense.

[ErkanTR16]

Originally Posted by ryanpat198808

Hi everyone, whilst driving on the motorway at roughly 60mph for around 15 minutes I noticed the temperature gauge fall. The temperature falls from the usual temp near 120c (250) to above 90c. Is the normal for the b58 engine to drop temperature whilst driving at low revs for longer periods? Also my heating was on max too.

The Oil Temp decreased for me as well. This only happens when i switch to Eco Pro. When i switch back to comfort or sport the temp increases to normal readings. I find this to be really odd.

[ryanpat198808]

Might be normal but I will ask when I drop my car off to the dealership

[HighlandPete]

Originally Posted by ryanpat198808

Might be normal but I will ask when I drop my car off to the dealership

From your first post I thought your oil temperature was dropping back much more. Your posted picture shows the oil temperature in the range many of us see with the BMW 6-pot petrol engines.

My car (N55 engine) has always run oil in the 105° - 110°C range, in normal driving and typical UK temperatures. Ran a check this morning, to confirm the temperatures at 7° - 9°C ambient temperature. ECT was ~103°C; oil temperature ~105°C, running at 55 - 60mph steady driving.

Still worth a hidden menu check, both ECT and oil are in the same display.

[JimKden]

My B58 sits steady on temperature.

[sunny]

Water temp goes up and down all the time.
Your car is designed to run at range of temperature.(90c to 120c) or around there.
when you first start your car, the thermostat stay closed so the engine can get to designed running temp quicker and when your car warms up to 120c(or around there) the thermostat opens to circulate the coolant to cool down the engine. It does this over and over again.
The hot coolant goes through "heat exchanger and blown air from that is the heater air.
So when you used max heater, you extracted heat from your coolant.

[Wires]

OP, to answer your question: Yes.

You are looking at oil temperature, not coolant (aka engine temperature). Under heavier load or stop and go driving, the oil temperature will increase. On the highway, the oil will start to cool and the temperature drops.

Perfectly normal. It's only a concern when you see the oil temperature substantially climb to the hot side.

[SlickShift]

As others have said, completely normal.

[zdzamatira]

Mine runs between 90 - 115 degrees Celsius and water pump only revs to 255rpm at a stop sign but when I am cruising its at 42 rpm I'm not sure if that is normal

[AspektUSA]

Only time I've noticed it move off of ~200*F is when it was -2*F outside and I was trundling along at 40mph in eco mode.