[Ramm440]

I just drove the wife's car and engine cooling fan is running a lot on high speed.

I did the water pump test and checked to see if coolant was flowing into the expansion tank and yes it is via the small hose.

I acessed the hidden menu to ck the coolant temp and the highest it went was 40c. I live in AZ and that cant be right because it was 95 when I checked it. I grabbed my infrared temp gun and got to like 175f on the hose from rad to the pump.

Plugged a cheap scan tool in and no codes.

I'm thinking of changing the temp sensor first because of the radical discrepency from the menu temp and my infrared gun.

Most annoying is the fan screaming like a race car.

[gbalthrop]

Originally Posted by Ramm440

I just drove the wife's car and engine cooling fan is running a lot on high speed... I acessed the hidden menu to ck the coolant temp and the highest it went was 40c. [That's Hidden Menu 7.00 I presume? -- Did you also confirm same ~ 40C range ECTS (Engine Coolant Temp Sensor) signal using Scan Tool Parameter Readout?] I live in AZ and that cant be right because it was 95 when I checked it. I grabbed my infrared temp gun and got to like 175f on the hose from rad to the pump. [That's the Lower Radiator Hose you're using the IFR Termometer on? That should be 10 to 20C COOLER than the OFH at the Upper Radiator Hose, where the ECTS is located. That's coolant that has been COOLED by the Radiator.] Plugged a cheap scan tool in and no codes...

QUESTIONS:
1) Does the 328i have an N51 or N52KP Engine?
2) Do you have a Temp Sensor on the Lower Radiator Hose (Radiator Outlet Temp Sensor)? Many/Most N52KP engines in US do NOT have a ROTS, such as my 3/14/2007 build 328xi N52KP.

If you have a ROTS on the Lower Radiator Hose, THAT is the primary Sensor Input to the DME for Radiator Fan Control. AFAIK, if you did NOT have a ROTS, and the ECTS signal was false LOW (40C), the Radiator Fan would NOT be running.

The ECTS is the Sensor that provides the Input to the DME which you read either with Hidden Menu 7.00, OR with a Scan Tool reading the Live Data Parameter "Engine Temperature." Problem is, that is the signal (variable voltage) returned by the ECTS via the Connector & wiring, so even though you can verify the False Low signal by aiming your IFR Thermometer at the ECTS Housing on the front of the OFH, you still can't be sure it's NOT a Connector or wiring issue.

Ultimate test: Remove the ECTS Connector and measure the Resistance (Ohms) with one Multimeter Probe on each of the two Sensor spades. Resistance at 20C (68F) should be in range of 2,500 Ohms, and Resistance at 90C should be in range of 250 Ohms. If your Connector & wiring are OK, but sensor is BAD, then you should see a resistance in the range of 1200 Ohms and a Hidden Menu 7.00 or ECTS Parameter reading of ~ 40C when the IFR Thermometer shows ~ 90C with fully-warmed engine.

If your engine has the ROTS on the Lower Radiator Hose, you might check that as well (with engine OFF, and staying clear of FAN that can run with engine OFF ;-).

Please let us know what you find,
George

[Ramm440]

I do appreciate the response but not into this car that much. I would much rather work on my Samurai with the Sidekick 1.6. I thought I was getting close to figuring out why the cooling fan races like its at the Indy 500 but fk it wife wanted this pos car against my judgment so there. Drive it till it drops😘

[Ramm440]

Btw it Only has 80000 miles and looks perfect but a pretty face don’t mean sht

[ctuna]

This car can run at 4 different coolant temps depending on
Sensor Feedback. The coolant fan should not run all the time though.
That usually indicates the water pump has gone bad.

Water pump can be exercised without starting the car using the purge
procedure . But be sure to charge the battery before and after.

https://www.google.com/url?sa=t&rct=...ACmbfEgCbsVKeH

See page 67 in the above document.

[Mantraxalos]

I don't know if the cheap scan tools can access all the modules. Perhaps the water pump error can't be scanned using that tool.
Maybe if the default setting for a faulty temp sensor is to run the fan on high. I know from working on multiple E90s when the water pump is bad (or bad connection/ground to the pump), the fan turns on full blast.

Originally Posted by Ramm440

Plugged a cheap scan tool in and no codes.

[Efthreeoh]

Originally Posted by Ramm440

I do appreciate the response but not into this car that much. I would much rather work on my Samurai with the Sidekick 1.6. I thought I was getting close to figuring out why the cooling fan races like its at the Indy 500 but fk it wife wanted this pos car against my judgment so there. Drive it till it drops😘

Then why did you come here and ask for advice if you think the car is a POS and doesn't deserve any attention? George is the guru when it comes to electrical system issues. Sounds like it hurt your brain. Take it to a BMW shop if it is over your head.

[Dabrwright]

Originally Posted by Ramm440

I just drove the wife's car and engine cooling fan is running a lot on high speed.

I did the water pump test and checked to see if coolant was flowing into the expansion tank and yes it is via the small hose.

I acessed the hidden menu to ck the coolant temp and the highest it went was 40c. I live in AZ and that cant be right because it was 95 when I checked it. I grabbed my infrared temp gun and got to like 175f on the hose from rad to the pump.

Plugged a cheap scan tool in and no codes.

I'm thinking of changing the temp sensor first because of the radical discrepency from the menu temp and my infrared gun.

Most annoying is the fan screaming like a race car.

I had the same problem recently. Engine had been running cold for a while and then the fan suddenly ran on high speed
There were no codes until the fan started running high and then a code for ‘thermostat stuck open’ appeared
Check your coolant thermostat
Not sure if my water pump was on the way out as well but got a new pump at the same time as replacing the thermostat. Just in case