540I Problem

[bmw540i]

Well i drove my car yesterday night pretty roughly I was racing with my cousins 745i. After i came home in the morning i saw coolant all over where my car was parked well i took a look under my car and coolant was leacking what do you guys think caused that.

[CalvinH]

Sorry, not enough info. Is it a little or a lot? one pint of fluid covers a lot of floor space but isn't a large percentage of the system capacity.

Did you put it away hot? If so, and you would be lucky, maybe what you see is merely overflow - check the level the system probably needs topping. Can you by looking under the car and under the hood identify the point of exit for the fluid?
Otherwise, you should start it (again after checking fluid levels), pop the hood, and look and listen. Any noise from the area of the waterpump? Any evidence of where the fluid exited the system?

Just a few thoughts,
CalvinH
2003 540i6 Black Sapphire Metallic on Sand

[kowached]

I would look at the:
-little plastic elbow on the pass side top of the radiator
-where the sensor inserts on the bottom of the coolant reservoir tank
-a fracture (where my $ is) at the top radiator hose on the passenger side, or a fracture along the side plastic of the radiator right below it, this is too common of a problem...


Report National Highway Traffic Safety Administration?

I demand the ability to be able to purchase a radiator from BMW that I will not expect to fail between 45-100k miles after I install it! I***8217;m not asking for a recall, but that would be nice, but I drive my cars forever and it makes me sick to my stomach that I just purchased a replacement radiator that will most likely fail me again during the time that I own this car.

I believe this to be a safety problem that BMW needs to address and the best way to get their attention is to report it to the NNTSA.

This safety problem:
- Disables the vehicle no matter where you are from rush hour traffic where the panic could endanger other drivers, to the middle of nowhere in the dead of winter by yourself.
- Steam from failed radiator blocks vision of the road, or whatever else is in the drivers side front corner of the vehicle.
- Failure can not be predicted by visual inspection of the radiator.

If you***8217;ve had this problem I invite you to join me and be heard by BMW in hopes of providing us a radiator that will make our cars safer. Don't give me any lip service here, I don't need it. Many people say that they'll do it, but the last time I looked I only found 4 reports, one of which was mine. Do it or don't.

Report your failure here: http://www.nhtsa.dot.gov/cars/problems/ivoq/default.htm

Survey: http://www.votations.com/asp/survey.asp?pollid=66461

Results: http://www.votations.com/asp/surveyresults.asp?pollid=66461

Radiator thoughts:

Failure is pressure related? I think that this is a long shot. The 528i and the 540i use the same coolant reservoir cap, and it is this cap that regulates cooling system pressure. An additional note would be that higher RPM makes the water pump spin faster and create additional pressure to be blown off, and the I-6 can out-rev the V-8 any day of the week yet this problem is almost exclusively a V-8 problem.

Failure is torque related? This may be more feasible. Does the upper radiator hose tug on the top of the radiator under load? Maybe. This may be what BMW suspects as well, which is why the later model 540i's have a slightly longer upper radiator hose.

Failure is heat related? The underhood temperatures of the V-8 are higher than the I-6 and may be a contributing factor.

Is the aftermarket Nissens replacement radiator less likely to fail than a replacement BMW OE radiator from Behr?

Victims list:
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1319565
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1321581
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1325680
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1443531
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1500846
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1596517
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1653091
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1655681
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1671213
http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=1710192

[bmw540i]

Thanks for your reply kowatched.

The wierd thing is that a couple of months ago before this happened the radiator cracked where the main hose attaches so they replaced it and then this happened. I think youre right it is on the passenger side because there was coolant all over the passengers side there was none on the drivers. I'm going to take the car to Pacifica BMW which i hate but i have to. I guess the V8 have radiator problems ha oh yeah and the car is only driven for 33000.

[kowached]

With the additional info that your radiator was replaced a few months ago, I now have my $ on a failed coolant expansion tank. It would appear that they fail like clockwork 4-6 months after radiator replacement. I did not beleive that, so I did not replace mine when my radiator failed, you guessed it, it started leaking, on a weekend when I could not get parts, thankfully I was not out of town with it.

Insist on a new fill cap for the coolant expansion tank, buy it yourself if need be. It is the only thing that regulates pressure in the system, and is only about $10. Cheap insurance.

[bmw325]

Curious-- Are there any aftermarket radiators which address this problem? If not, I'm kind of surpirsed-- the aftermarket has come up w/ replacements for other chronically bad BMW parts like water pumps.

[bmw540i]

Well they told me that it wasnt the radiator instead it was the anti freeze tank or something like that.

[kowached]

It seems that every coolant expansion tank fails within 3-6 months after having a radiator replaced. Let this be a lesson, if you get the radiator replaced, insist on a new coolant expansion tank, even if it comes out of your pocket (ditto on the pressure cap for the tank).