[AngryInch]

Anyone else notice their coolant temp dropping when on the highway after city driving? I hit the freeway home and noticed the coolant temp drop a few mm under the 100c mark... Typically its slightly over 100c driving around town...

[Maverik259]

Originally Posted by AngryInch

Anyone else notice their coolant temp dropping when on the highway after city driving? I hit the freeway home and noticed the coolant temp drop a few mm under the 100c mark... Typically its slightly over 100c driving around town...

Lot more air flow over the engine…pretty standard.

[F30Andy]

The one on the dashboard is oil temp, how do you get to see your coolant temp?

[phoenixbmwlife]

Originally Posted by F30Andy

The one on the dashboard is oil temp, how do you get to see your coolant temp?

I think he means engine temperature.

[AngryInch]

Originally Posted by Maverik259

Lot more air flow over the engine…pretty standard.

No, its not pretty standard, most engines have spring pressure thermostats that regulate operating temp ~95c, most of my vehicles regulate around that temp, but this M5 seems to drop down quite a bit from normal operating temp which is usually slightly over 100c... I guess it might be hard to tell since there isn't a numbered digital read out how far its actually dropping, but it seems like quite a bit.

[AngryInch]

Just drove 400km to the mountains at about 140-150kmh, car ran slightly above 100c…

It seems to drop when rip around town and after hitting a freeway for a min or two…

[MysticBlue]

I haven't looked into the specifics of this M5, but on previous M's (and non-M's for that matter) that I've owned, the temp gauge isn't really connected directly to coolant temperature in the classic sense of direct temperature reading. It's a gauge who's output comes from the computer, which is an amalgamation of oil temp and coolant temp and who knows what else.

[pbonsalb]

My 2018 runs at 250F. I almost always drive in efficient mode. Time in Sport mode is intermittent and I have never paid attention to see if oil cooling is better then.

250F is 120C. I agree it is hotter than I would choose and probably done for fuel economy. Likely someone makes lower temp thermostats but I am not sure whether coding or tuning is needed for any related computer stuff.

[Pugnacious]

2018/2019 M5 temperature gauge measures oil temperature. Fully synthetic oils can run at temperatures above 150c/300f so a fully warmed up reading of 120c/250f is fine. 2020 and newer M5's measure coolant temperature. If your oil temperature was only getting up to 100c/212f when the vehicle was full warmed up you would cause water buildup in the crankcase as the oil would never get hot enough to boil off condensation that forms when the engine oil cools to ambient temps.

[e92hunter]

Originally Posted by Pugnacious

2018/2019 M5 temperature gauge measures oil temperature. Fully synthetic oils can run at temperatures above 150c/300f so a fully warmed up reading of 120c/250f is fine. 2020 and newer M5's measure coolant temperature. If your oil temperature was only getting up to 100c/212f when the vehicle was full warmed up you would cause water buildup in the crankcase as the oil would never get hot enough to boil off condensation that forms when the engine oil cools to ambient temps.

The LCI M5 gets both, you can use the dash button to show Coolant Temperature. You already get the oil temp on the side so you can see both.

[Maverik259]

Originally Posted by AngryInch

No, its not pretty standard, most engines have spring pressure thermostats that regulate operating temp ~95c, most of my vehicles regulate around that temp, but this M5 seems to drop down quite a bit from normal operating temp which is usually slightly over 100c... I guess it might be hard to tell since there isn't a numbered digital read out how far its actually dropping, but it seems like quite a bit.

It is standard that when you run this car in hotter temps at higher revs it will run hotter than normal. It's a major heat soak with the V turbos. So if it's colder outside and you're not pushing it and the coolant doesn't have to open as much to cool the engine it will run slightly cooler. There isn't anything designed to warm the engine up besides keeping the coolant closed. But if ambient weather cools the engine below what you see as normal that seems pretty thermodynamically sound. Either way.

It's also electronically controlled vice mechanically if I recall a previous post discussing "colder" thermostat mods. I did one on my AMG but the main issue discussed here is that since the ECU controls it, how effective would it be. Either way I'm generally not concerned if my engine is running cooler than normal. Especially when it's cooler outside as you stated. Maybe it just hadn't warmed up all the way yet. Maybe it's just taking longer.

[bimmerbeast7]

Originally Posted by MysticBlue

I haven't looked into the specifics of this M5, but on previous M's (and non-M's for that matter) that I've owned, the temp gauge isn't really connected directly to coolant temperature in the classic sense of direct temperature reading. It's a gauge who's output comes from the computer, which is an amalgamation of oil temp and coolant temp and who knows what else.

there is an oil temp gauge and a coolant temp gauge. coolant will be best advice on realtime temp of the motor block.

[bimmerbeast7]

Originally Posted by F30Andy

The one on the dashboard is oil temp, how do you get to see your coolant temp?

Press the top button on the tip of the left hand stalk coming out of the steering wheel it will bring it up on the center of the right hand side of the speedometer

[bimmerbeast7]

Originally Posted by Pugnacious

2018/2019 M5 temperature gauge measures oil temperature. Fully synthetic oils can run at temperatures above 150c/300f so a fully warmed up reading of 120c/250f is fine. 2020 and newer M5's measure coolant temperature. If your oil temperature was only getting up to 100c/212f when the vehicle was full warmed up you would cause water buildup in the crankcase as the oil would never get hot enough to boil off condensation that forms when the engine oil cools to ambient temps.

So you've heard stories about horse cum in the heads of motors.. but u dont quite have it right ...

Optimal operating temperature range for motor oil is 180-220°F
Which makes you love BMW even more as it always keeps my oil at 190-200.. only when driving it hard will it touch 217°F

Dudes get horse cum in their motor from never getting their motor up to operating temperature (200°F) .. like driving only 3 miles to work or keeping it in the garage all the time and only driving it a few miles to get gas and then back to the garage for months and months

but 250°F?? hell no. your motor is too hot if it goes over 220°F

[bimmerbeast7]

Originally Posted by Maverik259

It is standard that when you run this car in hotter temps at higher revs it will run hotter than normal. It's a major heat soak with the V turbos. So if it's colder outside and you're not pushing it and the coolant doesn't have to open as much to cool the engine it will run slightly cooler. There isn't anything designed to warm the engine up besides keeping the coolant closed. But if ambient weather cools the engine below what you see as normal that seems pretty thermodynamically sound. Either way.

It's also electronically controlled vice mechanically if I recall a previous post discussing "colder" thermostat mods. I did one on my AMG but the main issue discussed here is that since the ECU controls it, how effective would it be. Either way I'm generally not concerned if my engine is running cooler than normal. Especially when it's cooler outside as you stated. Maybe it just hadn't warmed up all the way yet. Maybe it's just taking longer.

Running high revs/running hard in a hot environment will make any motor hotter

[bimmerbeast7]

Originally Posted by AngryInch

No, its not pretty standard, most engines have spring pressure thermostats that regulate operating temp ~95c, most of my vehicles regulate around that temp, but this M5 seems to drop down quite a bit from normal operating temp which is usually slightly over 100c... I guess it might be hard to tell since there isn't a numbered digital read out how far its actually dropping, but it seems like quite a bit.

hotter engine temperatures equal higher efficiency(Toyotas and lesser cars that they try and sell on efficiency they set to run at higher temperatures because you get better gas mileage that way)

lower engine temperatures equal higher performance (m car setup)

They build M cars to run cooler because motors makes more power at cooler temperatures (And you'll hear educated individuals say that coolant systems on m cars are very well sorted)

beginner stuff here.


intercoolers purpose is to push fluid through it and lets air pass through it to cool that fluid.

more air and cooler air = better cooling and lower temps

so of course if you're in stop and go traffic your motor is relying on only the fan to push air through the intercooler as opposed to you actually driving and the big grills and inlets on the front of the m5 are able to gobble up some air and pass it through the intercoolers and cool the motor, coolant, and oil all much better and more efficiently

I assure you the car likes to run at about 185-190° for the most power and once you push it hard it will get up to 210 220 but not any higher if it does you need to stop driving it so hard and chill out and let it get air (A.k.a. drive it at a decent speed at low RPM , not stop at a red light..)

and never cut your car off hot. never. worst thing for a motor

Ive found 2500 RPM pulls coolant through the motor fast enough but it's low enough RPM that it can cool and cools it the quickest

Cruising in Top Gear at 1500 RPM doesn't really push coolant through the motor fast enough and doesn't do the best job at cooling

my F10 was tuned with downpipes and it never went over 212°F
unless it was over 85°F outside

hot air doesnt cool very well

Most interesting part I learned from the F10 though was if I drove over 100 miles the oil and coolant temperature would get better and better at stabilizing and both would get 190°F and wouldn't budge because all the oil and coolant had fully passed through the system and was all fully acclimated

fun stuff

[pbonsalb]

These intercoolers are air to water units. Air from the turbos passes through and coolant in them that is cooler than the air cools the air. Since the coolant is absorbing heat, it is then pumped through an additional radiator to cool the coolant so it can keep doing the work of taking heat out if the air. The intercooler coolant system is entirely separate from the engine coolant system and operates at close to ambient outdoor temperature.

As for engine oil and coolant, oil runs hotter than coolant and it should. As others noted, condensation from warming up a cold engine can add a tiny bit of water to the oil and the oil needs to reach the boiling temperature of water or 212F to eliminate that water.

It is perfectly OK to have oil much hotter than coolant. Modern oils can handle 250F no problem. Coolant temperature should be lower. Pressurized coolant might not boil until 265F, but running the engine that hot can result in detonation. I agree with sticking to the range of 180-220F for coolant if possible.

I have actually not yet paid any attention to the coolant temp. I will take a look. Down the road, if I keep the car, I will look into modifications for the cooling system, oil cooling system, and air to water intercooling system. For now I am OK with the performance in the relatively cool New England area where I live, with just a JB4, 93 pump gas and water methanol injection.

[Pugnacious]

Originally Posted by bimmerbeast7

there is an oil temp gauge and a coolant temp gauge. coolant will be best advice on realtime temp of the motor block.

Your statement is incorrect. Coolant does not circulate through the "motor block". Engine coolant only circulates around the piston cylinder walls and through the heads which generate a lot of heat and heat up quickly due to their close proximity to the combustion process. Coolant can get up to operating temps in only a mile or two whereas the engine oil can take 5 to 10 miles to get to full operating temps.

Originally Posted by bimmerbeast7

So you've heard stories about horse cum in the heads of motors.. but u dont quite have it right ...

Optimal operating temperature range for motor oil is 180-220°F
Which makes you love BMW even more as it always keeps my oil at 190-200.. only when driving it hard will it touch 217°F

Dudes get horse cum in their motor from never getting their motor up to operating temperature (200°F) .. like driving only 3 miles to work or keeping it in the garage all the time and only driving it a few miles to get gas and then back to the garage for months and months

but 250°F?? hell no. your motor is too hot if it goes over 220°F

What don't I have quite right? The F90 M5 engine oil normal operating temperature is in the 250°F+ range.

[BlueString]

There's so many electronics in this car, you pretty much have to rely on the car's fault message prompts to notify you if there is an issue. When BMW decided to do away with the dipstick for the oil, I had to just rely on the system to tell me when I needed to top off the oil on my F10 550i and same now with the F90 M5.

[bimmerbeast7]

Originally Posted by Pugnacious

Your statement is incorrect. Coolant does not circulate through the "motor block". Engine coolant only circulates around the piston cylinder walls and through the heads which generate a lot of heat and heat up quickly due to their close proximity to the combustion process. Coolant can get up to operating temps in only a mile or two whereas the engine oil can take 5 to 10 miles to get to full operating temps.

What don't I have quite right? The F90 M5 engine oil normal operating temperature is in the 250°F+ range.

Just want to preface this by saying I'm not trying to start an argument but I do love a nice conversation about oil and preservation and maintenance

but normal operating temp is 180°F to 220°F ..

If either your coolant tip or oil temp is reading 250°F your car is crying for you to take care of it and let/help it cool down

[Pugnacious]

Originally Posted by bimmerbeast7

Just want to preface this by saying I'm not trying to start an argument but I do love a nice conversation about oil and preservation and maintenance

but normal operating temp is 180°F to 220°F ..

If either your coolant tip or oil temp is reading 250°F your car is crying for you to take care of it and let/help it cool down

Honestly, I too am not trying to be argumentative but the oil temperature gauge on my 2019 M5C has three temperature readings in Fahrenheit: 160/250/340.

When my M5 is fully warmed up after 5 to 10 miles of driving the temp stays right at the middle 250F mark. The 2018/2019 M5 had the "old style" instrument display. I have never seen the newer display in person but I did find an image of a 2021 UK spec M5C on the internet and it was clearly marked 100C with the little oil symbol under the °C marking. Now I am assuming that is the oil temp but I know the newer display has a lot more features than my 2019 M5 and as some have stated on this thread you can read both coolant and oil temp on the newer M5 whereas my 2019 M5 only has a idiot light for coolant.

So my seemingly stupid question is, do the 2020 and newer M5's with the new instrument display run at a lower oil temperature (100C/212F) as my 2019 is running great with no oil consumption at 250F.

[AngryInch]

My 21 runs oil at 100c.

Coolant runs slight over 100c, then randomly drops like there is a second thermostat that opens.. It must drop down to around 90c or lower, its a very noticeable drop.... A solild 2/8th or 1mm under 100c mark...