Coolant Leak Issues

Last month my low coolant light went on and after a quick visit to my BMW service center, it was determined that the coolant level was low (Obviously). Thereafter the coolant was topped off, and as a result the low coolant light went off.

However, the following week, the light went on again while I was driving and a short distance later it went off. This process then repeated for about three more weeks, in which the low coolant light would randomly go on and off while driving. Sometimes, it would go on and off three times over the course of 6 miles of driving, and on some days it wouldn't go on at all. I decided that it was time to take it back to the service center to get it fully checked out.

For the past five days, the service center has been unable to correctly diagnose what is causing the issue/the exact location of the issue. The mechanics informed me that there isn't any visible leakage of coolant in the engine bay/under the car and that they have been unable to find where any leakage is occurring, but that the system is constantly loosing coolant after it is replenished. They also informed me that when I brought the car in, there was absolutely no coolant present at all. This bothers me because the low coolant light should stay on if low levels of coolant are present, not to mention the absence of all coolant. Also, how is it possible for a BMW to run without coolant?

Does anyone have any idea as to what the issue could be? If the coolant's absence is not due to a visible leak, then what could it be? Not to mention, why would the low coolant light be randomly going on and off? My BMW warranty ends this April and I don't want to have bigger problems on my hands that will cost me a lot of money after the warranty ends.

Additional Notes:
I'm not sure if this is relevant, but over the past few weeks, the coolant temperature gauge on the dashboard showed that the coolant's temperature was normal (The needle was half way between both ends of the gauge) even with the low level/absence of coolant.
Also, a few days before bringing my car to the service center, I needed to jump start it. I'm not sure if an electrical issue could have made matters worse for the coolant system, but the service center informed me that the battery needs to be replaced and I am doing just that.

Thank you for your help!

Not to sound facetious, but the issue appears to be that the tech. is unable to find the leak. That coolant loss is not due to evaporation, guys.

I recommend you escalate the issue to the Svc Mgr. and/or BMW Regional svc. rep. Also, I would not rule out filing a complaint with the NJ Consumer Affairs Bureau...don't mean to be encouraging legal warfare, but the darn car has a coolant leak!

relinuca

I'll take an experienced guess: the leak is on the coolant reservoir right around where it branches of for the return line of the cabin heater. It's a stress fracture on the seam of the mold. You don't normally see since water seeps out only when the system is pressurized. Tell the tech to warm up the car and disturb that general area by applying pressure to the reservoir or gently wiggling the coolant return line.

1) how many miles?
2) go to a different stealership (I wouldnt go to any of them)
3) coolant sensor?
4) Depending on mileage, if high I think you need a cooling system overhaul

Originally Posted by jdauria

1) how many miles?
2) go to a different stealership (I wouldnt go to any of them)
3) coolant sensor?
4) Depending on mileage, if high I think you need a cooling system overhaul

J -- I have a different take.

I am willing to bet this is a very low milage x3 since it is still under warranty....maybe in the 20k mile range.

With that said, it isn't a cooling system that needs to be refreshed or a sending unit that is bad...although a slight expansion tank leak is a possibility. This is a post lci n52 motor...a simple proactive full refresh isn't really cost effective.

I actually am siding with a different answer...mostly based on assumed low miles....

Low coolant at around 20k miles is extremely common. Heck motor trend even reported it on their long term test of the 11:

http://www.motortrend.com/roadtests/...e28i_update_9/

I even had the same issue right at about 25k miles. The expansion tank was nearly empty. Filled it up, now at 107k never had another issue. What happens is the cooling system gets slightly bigger as the hoses expand and then some evaporates out.

Now with the above said here is what I would do:

1) find a trusted Indy shop and pay the $150 - $200 to have the car fully inspected to find any Warranty issues that need to be fixed before it expires...they will know what they are.

2) take that list to another BMW dealer and have them fix them

3) enjoy your x3! It is a great car that will last a long time with proper maintenance.

Originally Posted by x3brian

J -- I have a different take.

I am willing to bet this is a very low milage x3 since it is still under warranty....maybe in the 20k mile range.

With that said, it isn't a cooling system that needs to be refreshed or a sending unit that is bad...although a slight expansion tank leak is a possibility. This is a post lci n52 motor...a simple proactive full refresh isn't really cost effective.

I actually am siding with a different answer...mostly based on assumed low miles....

Low coolant at around 20k miles is extremely common. Heck motor trend even reported it on their long term test of the 11:


I even had the same issue right at about 25k miles. The expansion tank was nearly empty. Filled it up, now at 107k never had another issue. What happens is the cooling system gets slightly bigger as the hoses expand and then some evaporates out.

Now with the above said here is what I would do:

1) find a trusted Indy shop and pay the $150 - $200 to have the car fully inspected to find any Warranty issues that need to be fixed before it expires...they will know what they are.

2) take that list to another BMW dealer and have them fix them

3) enjoy your x3! It is a great car that will last a long time with proper maintenance.

thats good information brian. did know that since I don't have a 07+ x3.

So basically draining coolant, filling it back up, bleeding correctly should fix the problem?

I was meaning the refresh isn't necessary more so because it is potentially a low milage car.

The expensive part is the electric water pump. It alone is $400 and is an 8 hour job to replace...fun...

In most instances, opening up the bleeder screw and filling the expansion tank is enough.

Originally Posted by x3brian

I was meaning the refresh isn't necessary more so because it is potentially a low milage car.

The expensive part is the electric water pump. It alone is $400 and is an 8 hour job to replace...fun...

In most instances, opening up the bleeder screw and filling the expansion tank is enough.

Okay cool, awesome information again. Listen to the man!

Originally Posted by x3brian

In most instances, opening up the bleeder screw and filling the expansion tank is enough.

It seems like this has done the trick... so far. After almost a week at the service center, they completely emptied out the tank, refilled it, and made sure that no air was present in the system.

The service manager told me that what probably happened was that when we came to top it off the first time, the car didn't have enough initial time to cool down. The result of this was that the added coolant retained air in the reservoir, which ended up causing the coolant to disappear. I was informed that if anything happens within the next few months, that it will be covered without any problems.