2004 X3 overheat. Need help!

Originally Posted by toshiba

I decided to go ahead and installed a new thermostat today, no flushing coolant, just added the missing. The electric fan still not working. The car run fine at 40 mph, and at idle, while the AC was turned to level 2 for about 20 mins. Then we parked and let it idle with AC set to highest. Then temp needle started to raise to hot red. We shut the engine off. Again, radiator fan still not rotating. I think I narrow it down to the fan. I thought it could be the temperature fan switch.

Why a new thermostat? we ruled that out since the begining. Failed T-stat will make the engine run cooler and/or longer times to get to OT (Operating Temperature), never to overheat. (there are exceptions to the rule...)
To me it is obvious that the problem is electrical, not mechanical. When you say "while the AC was turned to level 2 for about 20 mins." Was the fan ON? It is ON at all or just sometimes?
At 40MPH, there is enough air circulation through the radiator to keep the engine at OT.

Originally Posted by toshiba

Is the electric fan on 2004 X3 supposed to turn on when the AC "snow flake" button is pressed at any time?

Yes and no.
The fan is supposed to start running at low speed as soon as you start the engine and increase/decrease speed depending on the engine and ambient temperature. The fan motor is a variable speed type, so when your AC is on it adjust accordingly as well.

To test your fan the right way, you need to put 12v from a BATTERY and see if it turns, if it does, then is something else in the circuit. (like the thermo-switch)
You said you did check all the fuses right?

Originally Posted by X3-terrestrial

Why a new thermostat? we ruled that out since the begining. Failed T-stat will make the engine run cooler and/or longer times to get to OT (Operating Temperature), never to overheat. (there are exceptions to the rule...)

Damn right there are. I've never had a thermostat fail in the open position and I've had my fair share of stuck thermostats. They got stuck in the closed position and caused overheating from lack of coolant circulation. I'd call this the rule, not the exception.

I totally agree though that the OP's problem is electrical. That electric auxiliary fan should come on at some point.

Originally Posted by Ishniknork

I'd call this the rule, not the exception.

I'd call it really bad luck!

We took it to a foreign auto shop for diagnosis, and they said it the electric cooling fan. They quoted me a crazy price to replace the fan assembly and lower and upper hoses. I'm looking for a cheapest way (DIY) to save money. Really appreciate any help or ideas. Is there fan replace diy for my x3?

You're probably out front on this one.

I would suggest a fresh printer cartridge, a ream of paper and a 24hour subscription to:

http://www.bmwtis.com/

Originally Posted by toshiba

I'm looking for a cheapest way (DIY) to save money. Really appreciate any help or ideas.

As the fan does not seem to be serving any useful purpose at present, here's what I would do:

- remove the unplugged fan assembly

- take it to an auto electric shop and see if they would replace/recondition just the motor

- look into temorarily installing a universal $100 electric fan (Flex-a-lite, etc.)

- check auto wreckers for an undamaged fan assembly

Before I order new fan, I'd like to test the current electric fan to make sure it's dead. Where do I connect the red (positive) and ground from battery to? The fan plug has three slots, which I think is positive, signal, and ground.
If I order used fan from the same year, is it going to be broken again, or should a fan coming from a newer 2005 X3 be a better choice (if it fits?)
Will the service manual dvd from ebay explain a little bit about the fan replacing process?

**Updated: The fan suddenly turned on today after about 2 mins of idling, plus AC on. The fan seemed to run at 2 different speeds. After 10 mins, the fan stopped. And now we couldn't get it run again, lol...I guess I don't have to replace the whole fan assembly, but something else. There is only 1 fuse in the glove box that indicate electric fan. We tested it a couple days ago, and it was good. Is there another fuse or fan relay I need to check also?

Originally Posted by toshiba

Before I order new fan, I'd like to test the current electric fan to make sure it's dead. Where do I connect the red (positive) and ground from battery to? The fan plug has three slots, which I think is positive, signal, and ground.
If I order used fan from the same year, is it going to be broken again, or should a fan coming from a newer 2005 X3 be a better choice (if it fits?)
Will the service manual dvd from ebay explain a little bit about the fan replacing process?

**Updated: The fan suddenly turned on today after about 2 mins of idling, plus AC on. The fan seemed to run at 2 different speeds. After 10 mins, the fan stopped. And now we couldn't get it run again, lol...I guess I don't have to replace the whole fan assembly, but something else. There is only 1 fuse in the glove box that indicate electric fan. We tested it a couple days ago, and it was good. Is there another fuse or fan relay I need to check also?

I think you're stabbing in the dark on this one. It's time to bite the bullet and hand it off to the professionals before you do some BIG TIME damage to something.

I don't know how much yours would be but a remanufactured N52 engine is over $9,000 not counting install.

Yup time to had it off to the professionals, it's a shame our BMWs are no longer as simple as E30s.

Originally Posted by toshiba

Before I order new fan, I'd like to test the current electric fan to make sure it's dead. Where do I connect the red (positive) and ground from battery to? The fan plug has three slots, which I think is positive, signal, and ground.
If I order used fan from the same year, is it going to be broken again, or should a fan coming from a newer 2005 X3 be a better choice (if it fits?)
Will the service manual dvd from ebay explain a little bit about the fan replacing process?

**Updated: The fan suddenly turned on today after about 2 mins of idling, plus AC on. The fan seemed to run at 2 different speeds. After 10 mins, the fan stopped. And now we couldn't get it run again, lol...I guess I don't have to replace the whole fan assembly, but something else. There is only 1 fuse in the glove box that indicate electric fan. We tested it a couple days ago, and it was good. Is there another fuse or fan relay I need to check also?

One thing we know for sure, it's not working properly. It was my first bet and the indy shop diagnosed it, you need a new fan.

I haven't done it before in the X3, but looking at it it should be a straight forward DIY.

Not sure what to advise you as I am not familiar with the wiring system to the fan. As it's variable speed I would suspect there is a thermostat which adjusts the speed based on the temp of airflow through the radiator. It can get expensive replacing parts until you address the problem and a thorough diagnosis can save you money. If you believe the opinion of the shop you took it to, you can buy a replacement fan and shroud from ebay for 260 bucks plus shipping. Here is the link. http://cgi.ebay.com/ebaymotors/BMW-X...Q5fAccessories

From what I have read there are a number of internal electronics within the fan including a timer so it's quite possible this is the problem. As for swapping this out, should be a fairly simple project although I have to admit to not having done this on mine as of yet.
Good luck

Originally Posted by toshiba

The fan suddenly turned on today after about 2 mins of idling, plus AC on. The fan seemed to run at 2 different speeds. After 10 mins, the fan stopped. And now we couldn't get it run again, lol...I guess I don't have to replace the whole fan assembly, but something else. There is only 1 fuse in the glove box that indicate electric fan. We tested it a couple days ago, and it was good. Is there another fuse or fan relay I need to check also?

So you have established that the fan is not dead entirely, so no need to test feed 12V to the terminal.

No point in looking further at fuses - they cannot cause an intermittent problem.

A relay could be sticky.
Could be a relay/control module built into the assembly itself as szee1 suggests.
Might be best to see how easy it is to remove the fan assembly for cleaning and checking.

Keep in mind these fans are not designed for continuous duty - so the cycling off after 10 mins. could be what it is meant to do.

Clearly, this is not a common problem, so we are guessing.
Have you done a seach on other BMW model forums for better clues?

A further complication is that third smaller pin - that could be fed by the CAN-bus rather than a straight connection to a temp. sensor.
Don't want to mess with that.
(Temp. sensors are usually just the ground return of a 2 wire connection AFAIK.)

Unfortunately, might be one of those cases where getting a dealer to read a fault code is the only way to get at the problem area.

Your engine is the M54B25. That, as an earlier poster stated, is the same motor that is found in the e46. If both of the radiator hoses are hot, then your water pump is working. It sounds like your electric cooling fan is on the outs. But no worries, it is not difficult to replace. Your car does not have a seperate aux air fan for the AC. The electric cooling fan does both. On older cars, like my e36, it was possible to overheat the car at idle with the AC on if the Aux fan was out and it was VERY hot outside. But on your car if the electric fan is out, then your car is not being cooled properly and it will overheat because again, you only have one fan now. They did away with the clutch fan, which in my mind is a good thing. Yoiu dont have to worry about replacing a fan clutch anymore.

So everyone can understand the M54 motors found in the early X3's have electric cooling fans. On the e46 cars you have the old viscous clutch fan. There is a big difference b/w the two. FYI the M54B25 and M54B30 motors may have either a metal impeller water pump, or one with a plastic impeller. When these cars start hitting 100k miles, we will begin to see coolant system failures as you see in every BMW built. There is no way around this. All of the components are made of plastic. With heat and wear over time all plastic components will fail. Modern BMW engines run VERY hot. They are designed to run that way due to emissions and fuel economy concerns. It is the nature of the beast.

BTW replace your coolant at least once a year. I was unaware that BMW considers their coolant "lifetime fill", I think a previous poster's SA was jerking his chain. BMW does not label their coolant as lifetime, like they do their driveline fluids.

hope that helps some

Originally Posted by bmwadam

On the e46 cars you have the old viscous clutch fan.

Except MT's

I got the electric fan replaced by BMW dealer for over $1100, with 2 year warranty/unlimited mile warranty. It's all good now. Just want to let you all know, in case you bump into the same problem one day. Overall, I replaced new thermostat, new coolant temperature sensor, which were not the cause of this overheating. The bad electric fan is the one. Don't know what to do with these extra parts other than keeping them till the day.
Thank You all for participating in this thread and helping a bmw fella out.

Originally Posted by toshiba

I got the electric fan replaced by BMW dealer for over $1100, with 2 year warranty/unlimited mile warranty. It's all good now. Just want to let you all know, in case you bump into the same problem one day. Overall, I replaced new thermostat, new coolant temperature sensor, which were not the cause of this overheating. The bad electric fan is the one. Don't know what to do with these extra parts other than keeping them till the day.
Thank You all for participating in this thread and helping a bmw fella out.

I'm glad you're up and running again. I know it's a steep price to pay but it's part of owning a high end car. I'm hoping mine will be trouble free until it's paid off so I can build up a little cushion for the inevitable high cost repairs.

Originally Posted by toshiba

I got the electric fan replaced by BMW dealer for over $1100,

Glad it was fixed. You could have saved a bundle if you had done it yourself though. Dealer labor costs are just out of this world.

Originally Posted by X3-terrestrial

Glad it was fixed. You could have saved a bundle if you had done it yourself though. Dealer labor costs are just out of this world.

The third wire was the real problem in his case. It indicated to me that the speed control was in the fan and without a diagnostic flow chart and a multi-meter there was probably no way to know for sure whether it was the fan or the signal going to the fan. A $30.00, 24hour subscription to BMW TIS would have been well spent in this case.

You've gotta know where to put the X.

Originally Posted by rs6655

The third wire was the real problem in his case. It indicated to me that the speed control was in the fan and without a diagnostic flow chart and a multi-meter there was probably no way to know for sure whether it was the fan or the signal going to the fan. A $30.00, 24hour subscription to BMW TIS would have been well spent in this case.

You've gotta know where to put the X.

True. But he mentioned an Indy shop diagnosed it too, so he already had the culprit. As I understand raeding back, he just "wanted to make sure"

Originally Posted by X3-terrestrial

True. But he mentioned an Indy shop diagnosed it too, so he already had the culprit. As I understand raeding back, he just "wanted to make sure"

My father was a GM tech for 38 years and one valuable thing I learned from him was to use factory shop manuals. Until now I have never owned a car without buying them (usually available from Helminc). The are expensive but very thorough and will usually pay for themselves the very first time you use them.

In this case a small investment and he would have been sure. Factory shop manuals have very logical diagnostic flow charts that if followed to the letter will rule out what it isn't and take you to exactly what it is.

Yup. I have the Bentley for my VeeDub, and I don't know what I'd do without it. The e46 Bentley helps on the engine and other "shared" parts, let's see when our Friends at Bentley Publishers think about X3's

Originally Posted by X3-terrestrial

Yup. I have the Bentley for my VeeDub, and I don't know what I'd do without it. The e46 Bentley helps on the engine and other "shared" parts, let's see when our Friends at Bentley Publishers think about X3's

I sure hope it's pretty soon. BMW Motorrad sells full shop manuals on CD for their bikes. I wish the automotive branch did the same.