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Discussion Starter #1 (Edited)
Before you ask, yes I searched. :rofl: While driving Greta home, I get the OBD ENGINE OVERHEATING flashing. Fortunately I have the water temps on my Navigation display thanks to Intravee II. The needle is straight up 12 o'clock. I was in city traffic, not bad stop and go. I watched the temperature go from 192ºF to 203ºF and then back to 190º. The ENGINE OVERHEATING warning turned on at 202ºF.

Once I got home and let it cool down some, I checked the coolant reservoir level and it was right at the neck. I checked for an obvious leaks and found none. The fan clutch was replaced in February 2014 at 91.5K miles and the serpentine belt was replaced September 2013 at 89K. She is due for a coolant change this month.

No unusual noises coming from the water pump and the fans are running properly. I'm perplexed. Would a defective sensor cause this issue? Also ran my Peake with no codes.
 

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Any leaks around the thermostat housing or other coolant leaks you can see? The only time I've ever gotten my motor hot and had a warning was when I replaced the thermostat, and pinched one of the O rings so there was a pressure leak with some liquid coming out. Thankfully it was a 20 degree day in november on my way home after fixing it at a friend's.
 
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I bet on an issue with the fan clutch or the aux fan.





PLEASE NOTE THAT I DO NOT OWN AN M5 AND THIS POST IS NOT INTENDED TO BE ARROGANT. PLEASE READ THE IMPORTANT REVISED DISCLAIMER THAT APPLIES TO THIS POST
 

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I had similar issues with water temp rising when in stuck in traffic but back to normal once at speed. I found that the aux fan was broken AND my radiator was totally blocked with straw/grass/feathers/dirt. Once I replaced the aux fan and radiator (though I suppose you could just clean it) all was fine.
 

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Discussion Starter #5
Any leaks around the thermostat housing or other coolant leaks you can see? The only time I've ever gotten my motor hot and had a warning was when I replaced the thermostat, and pinched one of the O rings so there was a pressure leak with some liquid coming out. Thankfully it was a 20 degree day in november on my way home after fixing it at a friend's.
No leaks that I can see.
 

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I bet on an issue with the fan clutch or the aux fan.





PLEASE NOTE THAT I DO NOT OWN AN M5 AND THIS POST IS NOT INTENDED TO BE ARROGANT. PLEASE READ THE IMPORTANT REVISED DISCLAIMER THAT APPLIES TO THIS POST
same issue happened with my e39 528i, there were no leaks but when replacing the fan clutch the issue went away.
 

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Odd. I've seen 96C water temp on my dashboard (climbing the hills out of Folsom on a very hot day last summer), which is about 205F and got no warning. Needle was still straight up and down at 12 oclock.
 

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I had a similar experience, but at 120k miles plus and just overhauled everything. The only thing I found with an issue is the waterpump bearings ground quite a bit when I turned it by hand once removed. I believe the water pump was on it's way out.
 

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Discussion Starter #9
Welp, got a call from the Dealer. The guys could not replicate the problem.

They thought it might be one of the sensors for the thermostat or radiator on its way out. I agreed and will keep an eye on it. Maybe Greta is still a little pissy?
 

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Welp, got a call from the Dealer. The guys could not replicate the problem.

They thought it might be one of the sensors for the thermostat or radiator on its way out. I agreed and will keep an eye on it. Maybe Greta is still a little pissy?
She wants one final shot at getting tarted up. Dump a few grand into her one last time!
 

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Discussion Starter #12
There could be air bubbles in the system. Try opening the reservoir, then running the heat at full blast and watching how much the level drops. If it's significant...there was air in the system. Once you figure out if there is air in the system or not, then try tackling the fan clutch.
Will try that when I bring her home.
 

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Can you read codes? Do you have a 35 (hex) for the aux electric fan? It is the primary cooling fan, especially in stop/start traffic. The clutch driven fan is a backup.
 

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Everyone keeps pointing to a cooling system issue, but the temperatures you mentioned are not overheating and are in fact normal. I see about 205-210*F everyday now in the summer with the AC on. This sounds like buggy electronics. IMO, start with sensors and their connections. Check em and maybe see about verifying all fan electronics are happy. Codes?
 

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Discussion Starter #15 (Edited)
Can you read codes? Do you have a 35 (hex) for the aux electric fan? It is the primary cooling fan, especially in stop/start traffic. The clutch driven fan is a backup.
Everyone keeps pointing to a cooling system issue, but the temperatures you mentioned are not overheating and are in fact normal. I see about 205-210*F everyday now in the summer with the AC on. This sounds like buggy electronics. IMO, start with sensors and their connections. Check em and maybe see about verifying all fan electronics are happy. Codes?
I ran codes with my Peake with nothing. They ran the computer at the Dealership with no stored engine overheat code. They could not replicate the problem. While I was driving home, I replicated it. SMH I also have a feeling it's a sensor issue. My issue is that my Intravee was hitting 203º and tripping the ENGINE OVERHEATING OBD warning. Whether it may be normal or not, it shouldn't be tripping that warning.
 

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Everyone keeps pointing to a cooling system issue, but the temperatures you mentioned are not overheating and are in fact normal. I see about 205-210*F everyday now in the summer with the AC on. This sounds like buggy electronics. IMO, start with sensors and their connections. Check em and maybe see about verifying all fan electronics are happy. Codes?
Yeah, you're right. That message should not have come up until the gauge was in the red, which it wasn't apparently. And the two thermistors in the sensor on top of the t/s agree with each other quite well since the gauge position and the KTEMP reading seem to match. It just gets so damned complicated if the DME software is reacting wrongly to an acceptable reading, I was hoping the OP just got confused.....

EDIT: just read GB's post. He wasn't confused, so it just got complicated.

GB, when you say in your original post the message was "flashing", do you mean regular flashing or flickering? (I'm thinking intermittent broken wire or ground.)
 

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Discussion Starter #18
Yeah, you're right. That message should not have come up until the gauge was in the red, which it wasn't apparently. And the two thermistors in the sensor on top of the t/s agree with each other quite well since the gauge position and the KTEMP reading seem to match. It just gets so damned complicated if the DME software is reacting wrongly to an acceptable reading, I was hoping the OP just got confused.....

EDIT: just read GB's post. He wasn't confused, so it just got complicated.

GB, when you say in your original post the message was "flashing", do you mean regular flashing or flickering? (I'm thinking intermittent broken wire or ground.)
Flashing as "pay attention to me or else" :rofl:
 

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Discussion Starter #19
I don't want to state the obvious but you do know you set the intravee overheat warning to your own number? My intravee warns me at 112 degrees as the car typically runs at 110


Sent from AutoGuide.com Free App
Obviously that isn't obvious. I didn't know you could set your own warning on the Intravee. I will investigate.
 
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