seanjordan20

There is no programming involved with changing coolant system parts. You are looking at either a bad thermometer, motor or temp switch. Do you have a program to see if it measuring the temp right? Did you unplug the switch and forget to plug it back in?

Jeff Bergman

Ok so that helps. There's no programming. You never know with these cars you know. When I changed my battery, I was told that the computer had to be programmed to recognize there was a new battery to avoid overcharging it. Who would have thought that a simple battery change would require programming.

Ok so back to my issue. I don't have any software to check the coolant temp. I have an infared thermometer, but I'm not sure that's what you are referring to.

When you say the switch, are you referring to the sensor on the lower radiator hose? If so, I put a new sensor in and yes it's plugged in.

On a cold engine, do you know how long it takes after I start the car for the fan to come on? I tried turning on the AC, but nothing happened. Do you think I need to just wait longer? I ran the engine for 5 minutes and no fan. Maybe it didn't get hot enough??

Is there a way to force the fan to come on? I read something about unplugging the temp sensor. Is that the one on the lower radiator hose, or on the thermostat? I was also told it would cause a code but that code would reset itself in a few days. Does that sound correct??

I'm trying to avoid taking it back to the dealer after all the work I've done.

Thanks everyone for trying to help.

Jeff Bergman

ok here's an update. I could not find any 100A or 10A fuses. I decided to just start up the car and see what happens. Let it run in the garage for a bit. It's not a hot day; about 65 degrees. I turned on the AC. I noticed the fan came on "low speed" for a minute or so, then shut off. So the fan does seem to turn on. I could not get "high speed" out of it. Maybe it's just not hot enough?? I'm feeling like it's just not working right but can't pin point it. Does any of that help you pros out there give me more feedback??

Thanks guys.

twh

There is no reference to a water pump in that diagram. I was just saying that many people automatically assume you have a 6 cylinder BMW, which all have electric water pumps as of late.

BTW, RealOEM.com is very handy. See this diagram of your water pump:
RealOEM.com - Online BMW Parts Catalog

Those fuses are likely in the trunk on the passenger side behind the carpeted panel.

seanjordan20

Their are two fan speeds low and high. So we know that you are getting power to the fan now we need to know why it is not kicking over to high. Hhave you tried replacing the sensor with the old one to see if it makes a difference. The sensor should dictate when the fan cuts on. Once it reaches a certain temp the sensor sends a signal then the fan cuts on high. Yes I was referring to the coolant/engine temp earlier. Have you checked the temp with your infrared. Have you gotten an over heat error while running the car. If not then your car is not getting hot enough. I would check the thermo if the sensor swap does not make a difference. It might be stuck open for some reason. All cars takes different times to get to operating temps. But I would say around 10 mins max should get you there depending on fluid types used and size of engine. At 5 mins it probably should of kicked on.

I am just throwing some suggestions out there because I know how you feel about going to the dealer.

Jeff Bergman

Thanks for the feedback seanjordan20.

Are you referring to the sensor in the lower radiator hose? If so, will I have to drain the coolant to change the sensor to the old one??

No error messages re: engine temp during the 10 minutes or so I ran the engine.

What about the electric connection or sensor on the water pump? Is that something I should look at?

I heard a reference to disconnecting the temp sensor which would force the fan to run on high speed. Is that the sensor on the lower radiator hose?

No I didn't do an infared temp check. Where's the best place to point the laser to check temp? Radiator or block, OR???

Thanks for the help guys. The dealer will hit me with a $150 fee just to diagnose again. Then whatever they find??

seanjordan20

I do not know where yours is located. Mine is located on the passenger side 3/4 down the radiator so I think that is the lower hose. Either way no drain is necessary for the sensor to be pulled.

The block is where you want to measure temp at. I would not worry about the water pump. Is it not kicking on either? Yes disconnecting the sensor would kick it on because there is no way for it to tell what temp it is and it goes into "protection mode". I will start my car and get back with you and tell you how long it took mine.

park828

BMW n62 cooling system issues | BMW Logic7 site


be very careful if the fans dont work with ac on.

and dont even drive the car for a short short short distance when engine hot message comes on.

i've damaged my transmission because of it.

seanjordan20

Ok there is probably nothing wrong with your car. It takes a while for them to heat up. Either take it for a 5 min drive or let it sit for 20 mins running. My fan started working at 14:36. Which is well after a US car.

seanjordan20

park828 you must of drove it for a while with the Hot engine message. Do you know how long it take the trans cooler to over heat?