What is your engine operating temp?

I did not checked my temp for long time in hidden menu,but yesterday I changed some leaking tube behind throttle body and look at temp after driving, it was 105C. What is yours after driving? I am planning a long trip just want to be sure that i am alright. Thank you guys.

Depending on the driving it varies, and I have a 760 so it runs a bit hotter. One day in HEAVY HEAVY traffic where I moved 1 mile in 2 hrs, Temp was 118C Degrees. During regular driving it floats around 105C. During highway driving it ranges between 86C and 110C depending on my speed.

Glad you posted. After I did my coolant pipe last winter, I monitored the temp @ between 100 and 105C. Just last week I got a CEL and P0128 code that indicates the engine is running too cold / too long so I monitored the temp on my drive home from work (about 30 miles 50/50 hwy/cty). It warmed up to 90C and stayed there cruising @70mph on the freeway. When I got into some lights, it only got up to 92.
I picked up a new thermostat but didn't get a chance to install it last weekend so going to have to wait till this coming weekend. Hopefully that fixes the problem; I figure the thermostat is stuck closed or has a leak.

I think 105 is probably the normal temp. I thought I saw that when reading through some similar posts.

Thank you guys. I know my thermostat opens after some time, i can feel tube becomes hot on the other side of thermostat. I always thought if u have faulty thermostat your car should overheat not running cold?

Originally Posted by Khabar

Thank you guys. I know my thermostat opens after some time, i can feel tube becomes hot on the other side of thermostat. I always thought if u have faulty thermostat your car should overheat not running cold?

The thermostat in our car is designed to fail open...that means the car should run cold if the thermostat is bad....especially in cold weather. Besides checking the hose on the other side of the thermostat and easy way to check is open the coolant reservoir....turn on the heat in your car. From a cold start there should not be any coolant flowing to the reservoir especially with the heat on. After a few minutes if the thermostat is working right coolant should start to flow....if coolant flows right away as soon as you start the car then you have a thermostat that's stuck open.

are u sure about that DFEL750i?

Originally Posted by csmeance

Depending on the driving it varies, and I have a 760 so it runs a bit hotter. One day in HEAVY HEAVY traffic where I moved 1 mile in 2 hrs, Temp was 118C Degrees. During regular driving it floats around 105C. During highway driving it ranges between 86C and 110C depending on my speed.

Wow, you're gonna kill your engine and tranny very soon 118 means you've got air, just like I had! Get it out ASAP.
Set heater on high, Disconnect aux water pump and if you have no warm air coming from heater core, then start venting your system ASAP.
If you drive like this you'll get most favorite blue smoke symptom along with coolant pipe etc valve stems don't like 118C!
And don't worry your engine was not built to run a little hotter just bc it's V12 your temp should not be higher than 105C and actually 103-105C otherwise you've got cooling issues:
Assuming water pump and tstat are good:

Air in the system (heater core)
Coolant pipe seal is leaking inside

Ps. I'm so surprised these perfectly built engines can sustain this heat so good for so long, if it was Japanese or American engine, it would have gotten head gasket or head problem very quick. What I hate about it is that bmw don't want us to know when it's overheating !!!! Old bimmers had temp gauge where you could see it overheating.

Originally Posted by Khabar

are u sure about that DFEL750i?

Yes. Our thermostat will fail open to prevent overheating. Also when the car is cold and therefore coolant is cold there is no need for the thermostat to be open to run coolant through the radiator. If no coolant is being run through the radiator then there wont be any coolant flowing into the expansion tank.

Originally Posted by DFEL750I

Yes. Our thermostat will fail open to prevent overheating. Also when the car is cold and therefore coolant is cold there is no need for the thermostat to be open to run coolant through the radiator. If no coolant is being run through the radiator then there wont be any coolant flowing into the expansion tank.

-1 wrong. Check how your radiator is built my friend even with small loop it still goes through small radiator loop which cools tranny and alternator
So when your car is cold and you can see a coolant flow from small hose it's totally normal, and is not that good if you don't have it, bc it means coolant pressure loss either bc of waterpump or some leak

I have to agree here with SFbay. I know my thermostat is good and coolant was circulating the way u DFEL750I describe since i bought a car.It takes 1 mile run from a cold start for thermostat to open. Big engine 7 has.

Originally Posted by Khabar

I have to agree here with SFbay. I know my thermostat is good and coolant was circulating the way u DFEL750I describe since i bought a car.It takes 1 mile run from a cold start for thermostat to open. Big engine 7 has.

1 mile run?? Really?? I have 1000 doubts about it.
If you're saying its opened, how do you know?? Did you check lower hose?? I bet 1000$ it's going to be cold until your engine reaches 100-105C. Boil your tstat and you'll see that it starts working only from 100C. Before that its fully closed. Ppl who have more than 105C would notice that lower hose is cold even at 105C therefore aux fan won't kick in when needed.

maybe more than mile. I wormed my car all the way until line disappears from dashboard then drove 1.5. after hose became hot and fan kicked in. I am very disappointed in quality of hose connectors at end of coolant hoses. They use some kind of fiberglass material.

Originally Posted by Khabar

maybe more than mile. I wormed my car all the way until line disappears from dashboard then drove 1.5. after hose became hot and fan kicked in. I am very disappointed in quality of hose connectors at end of coolant hoses. They use some kind of fiberglass material.

Line disappears when temp is more than 70C and its not even close for tstat to open. When fan kicks in, this when tstat fully opened and lower hose temp is higher than 65C. Lower hose fan switch is actually temp sensor, not a switch how they call it.
Also you know that this tstat opens electronically if engine temp is higher than 105C no matter what temp you have at lower hose. This is that black connector is for, it's just a dme controlled heater inside your tstat. They installed it to prevent from overheating or if engine needs it to open earlier. Bullet proof design- but as we know here...

Coolant flow in the Engine Block
The coolant flows from the water pump through the feed pipe (1) in the engine's V and to
the rear of the engine block. This area has a cast aluminum cover (see following illustration).
From the rear of the engine, the coolant flows to the external cylinder walls and from there
into the cylinder heads.
The coolant then flows from the cylinder heads into the engine block V and through the
return connection (3) to the thermostat housing. When the coolant is cold it flows from the
thermostat (closed) directly into the water pump and back to the engine (recirculating for
faster warm up).
When the engine reaches operating temperature
(85 ºC-110 ºC), the thermostat opens the
entire cooling circuit to include the radiator.