danclements

Hi all.

Trying determine what the catalyst is for my big fan kicking in at 100%. Car is tuned and the setup has the fan starting slightly higher to deal with the additional heat generated.

We have had a few consecutive hot days here in AU of late; 4 days of 42c-45c temps (108f-113f). I'm finding that the big fan is kicking in within 10mins of driving lately. Oil temp below 60c, coolant below 80c, which is well below optimal operating temperature.

Is this based purely on ambient temperature? Or are there other conditions taken into consideration? e.g. air intake temps.

I may need to upgrade the cooling system to assist with this, but I don't drag or track this car and daily it, so don't want to go big if I don't have to. The divorced intercooler setup is on my radar.

Appreciate any feedback.

Cheers,
Dan.

EckFe1

Are you running the AC as well?
Fan runs when AC needs to cool condenser temp.

danclements

I drove it with the AC off to confirm if it was still occurring, and it's the same behavior.

sunil517

if not the fan is doing its job of keep the oil/coolant at a given temp.
Take it on the highway and get some air flow and see if the temps go up or stay the same.

danclements

Oil and coolant temps are perfect when warmed up. Oil sits anywhere from 94c-97c and coolant at 91c-94c. That's the reason I'm confused. Not sure what is making it kick in.

sunil517

make sure oil and water are now low also pop the engine cover and check the level of the IC level. It next to the ECU that is for the intercooler system. Make sure the pump by the passenger side head light is working that is the pump for cooler what is your IAT.
On every BMW I had when the fan is 100% is a sign of failing electric water pump or stat soon to follow by a CEL.

danclements

​​​​​​Thank you for the feedback, I really appreciate it.

I have a first gen M157, so the intercooler reservoir doesn't exist and is shared with the radiator. Fluids all look great. Oil was changed only 100kms ago and is fine. (was happening before and after)

How would I go about viewing IATs? I have a base level scanner, but not sure if it has full visibility of the ECU values.

I'll see about the water pump. Is there any real way to know it's under duress or not performing as well as it could be?

sunil517

the big bucks scan tool can turn on and off the fan check flow rates and opening of the stat. That is how I found the issue on my 535 turbo BMW. and I drove it till the CEL came up scan it again and it said water pump and stat not up to spec.
Turned out that it was not the water pump but only the stat. I changed the stat and that took care of it. maybe try bleeding the coolant for air and see if that helps. What I do once the car is cool I open the over flow and tap up unti lit takes no more. I am sure a vent bleeder is somewhere on this motor.
Does your fan work at any other speed? or just HI. Speaking with my friend he said when his fan faile 2014 E550 same fan as E63 ( I think) it would only run at HI. so maybe your coolant temp is telling the fan to turn on at lower temp and it is not.. It is waiting till HI to turn on. Scan it and they will be able to tunr on the fan at different speed.

e65

using trans temp on torque app, not sure if it's really recording the transmission temperature, when that reaches 104 celcius the fan goes to 100%.

it is slower at 103 and slower again at 102.

that is the best and most consistent correlation I've seen with the fan speed.

danclements

Thank you! I had no idea about this and have had intermittent trans issues for the last 2 years when out on spirited drives. It may very well be related. I really appreciate your feedback!

V-AMG