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Discussion Starter · #1 ·
Was wondering what the appropriate coolant/engine temperature range is in *F. My car is running at, what seems to be a high temperature range (240*F-275*F), but my coolant gauge says it is perfect (right in the middle of cold-blue and hot-red). If it is true about my suspicion, what do you suppose is the problem?

-I installed new thermostat and water pump, coolant temp sensor, cleaned radiator, and flushed the system with distilled water and drained/refilled completely. Coolant mixture is 50/50 and reads perfect with no air bubbles present.
 

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How are you getting a reading in F? The computer reports C. It should be almost exact 95C at all times, except under certain circumstances.
 

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Discussion Starter · #5 ·
How are you getting a reading in F? The computer reports C. It should be almost exact 95C at all times, except under certain circumstances.
You can change the setting, its very simple. Hit the right cluster button on the gauge panel. DONE!
So you are telling me it should be about 203*F? Ok so any ideas as to what my problem is?
 

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I cannot buy that that your engine operating temps are 240-275F, this is HIGHLY unlikely.

What part of the world are you in? What are the ambient outside temps?

Where/how are you reading these values?

Post a picture.
 

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Discussion Starter · #11 ·
To Jfoj,
Using bmw OBC function 7.0 and selecting Fahrenheit using the right cluster button on the gauge panel, I am able to see my coolant/engine temp. Learn how to do this yourself. And for the environment, I live in Arizona and the temp was 91 today...not to bad. I honestly believe that the coolant temp sensor is bad.


Sent from BimmerApp mobile app
 

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Engine should be running 96C/205F even at 91F outside temps.

I would expect things to be boiling over if you were running temps like you mentioned.

You need to get an OBDII Scan tool, you WILL need it.

Suggest you get an App for your smart phone and an interface, usually $35 or less for both.

Read this - http://forum.e46fanatics.com/showthread.php?t=967204

Also read the 3rd link below in my signature.
 

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In the summer w/ ambient around 85F or so, my coolant temps typically run at 86-95C at operating temp with fairly hard driving (even without the mechanical fan in place); temps actually decrease with hard driving where my temps are more in the lower 90's to high 80's under hard driving. With grandma-ish driving like it's a Toyota Camry, usually sits right around 95C +-3 degrees without the mechanical fan. In Summer in stopped conditions on the highway w/ the AC blowing, still maintains 95C +-3 Degrees even without the mechanical fan in place. Since someone stole my expensive OBDII reader that has realtime data output, I don't know what the temps are in the winter & haven't done the onboard diagnostic stuff because I can never remember how to do it...

Highest temp I've ever seen was 102C in 95F ambient weather in the sun, without a breeze, without the mechanical cooling fan, & without the AC running while idling in my driveway for about a half hour to see whether the car would overheat after I removed the mechanical fan because the fan clutch was making noise. W/ AC on in this 'test', temps dropped to around 98C because the auxiliary fan was constantly on. Even two summers ago w/ 110F ambient temps in W. Michigan in start/stop conditions, coolant temp measured a steady 95C +-3 degrees (AC was obviously on).
 

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Discussion Starter · #14 ·
Engine should be running 96C/205F even at 91F outside temps.

I would expect things to be boiling over if you were running temps like you mentioned.

You need to get an OBDII Scan tool, you WILL need it.

Suggest you get an App for your smart phone and an interface, usually $35 or less for both.

Read this - http://forum.e46fanatics.com/showthread.php?t=967204

Also read the 3rd link below in my signature.
I forgot to mention that I do have an OBD II reader and I have not gotten any codes. Any other ideas? I get that the temp is too high, that is obvious but I am wondering if it's because of a false reading from the coolant temp sensor or if it's a pressure leak due to a hairline fraction in the radiator.
 

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Discussion Starter · #16 ·
The gauge won't be in the middle at 275°F. Should be nearly maxed out at that temp actually
I have come to that conclusion already.
What I am looking for are any suggestions as to what the problem can be.
Please read the thread and comments above and possibly propose some solutions or ideas to troubleshooting.
 

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The problem is pretty obvious IF the temp gauge on the dash is almost maxed out, the Hidden OBC indicates the temps are too high and if you have an OBDII scan tool that can read Live/Real Time data and that tool reads high, then you have one of a few problems. I would not relay on the Hidden OBC menu for this task if you say the coolant temp gauge on the dash is centered. Get an OBDII tool that can read Live/Real Time data and see what the OBDII tools indicates. If you do not have a tool with Live/Real Time data, you need one. For under $35 a smart phone App and interface will do the job. Read this - http://forum.e46fanatics.com/showthread.php?t=967204

Either your coolant temp sensor or wiring to the coolant temp sensor is faulty.

There is an electrical grounding problem somewhere in the vehicle.

A possible air pocket in the cooling system, proper coolant system bleeding can resolve this.

A broken water pump impeller.

A bad thermostat that is causing the engine to run too high, but this is rare due to the thermostat design.

The engine could be running 275F, however, I assume this not to be the case as I would have expect boil over, expansion tank cracking and very poor engine performance. With heat soak on engine shut down the engine temp will rise, so if you are really running at 275F, I would expect when the engine is shut down the temps may climb close to 300F! I would have expected a catastrophic cooling system failure by now. Meaning coolant all over the engine and ground.

I kind of expect poor engine performance/loss of power either way due to a significant reduction in ignition timing if the DME is really being told the engine temps are this high whether or not they really are. The DME does try to protect the engine to some extent and loss of ignition timing advance is usually the way the DME addresses this. Loss of timing advance kills engine power quickly.
 

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Discussion Starter · #18 ·
Engine is fine and temp is fine. OBC was wrong. Coolant runs at perfect 95'C. Honestly it wasn't own damn fault. I had it set to the wrong OBC function subset. Thanks everyone for your contributions though. I'm only human, I make mistakes.
 

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After replacing nearly the entire cooling system in mine, radiator and all the hoses, pump, thermostat and well... everything, mine runs at around 195 F. to around 204.8 while sitting at fast food drive throughs. (sometimes reaching 206 F)
 

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After replacing nearly the entire cooling system in mine, radiator and all the hoses, pump, thermostat and well... everything, mine runs at around 195 F. to around 204.8 while sitting at fast food drive throughs. (sometimes reaching 206 F)
i have the same problem with my 05 bmw e46 330i was your issue fix and what was it.
 
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