BMW X7 E70 2007 only over heats if heater not at maximum 84 and max fan

[davidyun]

I know there is so much information I’ve been reading through.

Overheats if heater not full blast 84. Otherwise the fan doesn’t kick to full.
No leaks, burped multiple times and coolant level steady, water pump works.
Could it be something with a relay electronics?
Replaced expansion and hoses to it.
Maybe it’s the temp gauge not opening if heater is not at full?
Heater fan at half or 1 bar still overheats.

I have been trying to install ista for 3 days still a pain in the a. EDIT: Ista working now! Cable connection fixed.

Thoughts?
Thanks!
DA

[pshovest]

Sounds like the engine is running very hot and heat released thru heater core prevents the overheating.
Which engine?
Lots of possibilities.
How do you know it's overheating?
Did you bled the cooling system after replacing expansion tank?
Was it OK before replacing exp tank?
Unlock the hidden menu, go to test 7 and report the engine temp.

[davidyun]

6 inline. I replaced the tank and bled it multiple times on a current battery maintainer of 50 amps 14.4v
Not the first time bleeding, I have been with bmws for a while so I’m just a little confused whethe the thermostat opens only at high fan 84’ water pump works, fan works at variable speeds even when gassing it (with full heat on) agh I just wish ista would start working on my laptop. Hopefully I can see some figures … maybe sensors ,,,

[davidyun]

Oh I know it’s overheating because fan goes to full speed and then some time shortly later yellow and later red overheat warning. But still it doesn’t do that with full blast 84’ even if I drive around like a race car driver (for testing purposes) . Will keep updating but in case you’ve had before lmk. Radiator and hoses temp by touch… well to me didn’t seem like they have issues.. bmw adventures in the garage , right?

[andrewwynn]

I use bimmerlink to monitor coolant pump speed and fan speed as well as oil temp and coolant temp.

You need to know the actual temp to diagnose this.

You are describing the symptom of a weak coolant pump. Say if the pump is turning 2/3 speed the extra radiator aka heater core is pulling just enough heat to keep things under control.

Thermostat not opening properly, coolant pump not running full speed are the prime suspects.

You can at least monitor coolant temp from the hidden menu for starters.

I recommend getting bimmerlink

[davidyun]

Roger that TY so much. I don’t know why BimmerCode is not working with my dcan $25 clear wire ( connected to iPhone with usb c to usb adapter) … but maybe I’ll go ahead and buy the bimmer link for $39.99. Will update as I go along

[davidyun]

The scan cable seems to work on pc BimmerCode app. Ista now loads but says can’t connect. Going to pick this up in AM.

[andrewwynn]

Get a listed as compatible Bluetooth OBD dongle. I think I have veepeek. Wireless and I can leave in and use every drive.


Here’s my dashboard on my iPhone.

[davidyun]

Originally Posted by andrewwynn

Get a listed as compatible Bluetooth OBD dongle. I think I have veepeek. Wireless and I can leave in and use every drive. .

Morning.
Oh wow I didn’t realize it was only 30-40$ this should really help with com ports and all the posture that comes with a cable !
Thanks!

[andrewwynn]

Bimmercode also works with the OBD2 Bluetooth


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