Hello everyone,

I own a 2006 525D M-Sport (12,500 miles)

2 weeks ago I recieved a message on the dashboard stating "Engine Coolant Level is Low" I ignored the message and it has not poped up again till yesterday, yesterday it popped up again with the same message. There has been no message today.

I have searched on the forums, and in the DIY section but I have not found a definitive answer.

I know I should definitely use BMW Engine Coolant to top it up, but I have also read stuff regarding flushing the engine coolant or something, and topping it off with the engine running because air bubbles or something can come up?

Is there anyone who can help me here with a proper answer.


Kind Regards,
Cream Sauce

 

If you're only topping off with BMW coolant you should do that when the engine is "cool". However, since the system is closed any loss is suspicious. After 4-5 years it's not unusual for the plastic parts of a BMW cooling systems to start leaking from cracks that are barely noticeable! You should have a qualified BMW mechanic investigate ASAP.

 

Is there anything I can do, other than take it to a BMW stealer?

For instance (Just talking logically here): Actually check under the bonnet in the engine coolant reservoir if the engine coolant is low when the engine is cold and then after some driving when it is hot ? And if it is low get some topped up via my own mechanic, and if after some use it shows the same problems then get it checked by a dealer to see if a leak is the problem ?

Kind Regards,
Cream Sauce

 

Check underneath that part in the red box for any drops while the engine is running and hot and keep searching all the pipes and radiator for
any small cracks it's so hard to notice unless you have coloured coolant but most leaks comes from the refilling box and it's not that expensive and easy to replace.

 

I don't know if the diesel has sensors in the same locations as the V8 but check the temp sensor on the radiator return line and also on the radiator vent pipe as these are common points of leakage. If you open the fill cap on the reservoir after the car has run for some time be aware the reservoir will be pressurized with hot vapor. If you have to add coolant while the engine is still hot, be sure to go back and check it again when it cools.

 

I had a low coolant issue with my e46 before. What was happening was I had a cracked/weathered hose and coolant was leaking there but only when the car was warm. I never noticed the leaking because it would only drip when warm and then would drip onto a hot surface and burn off so I never so any puddles where I park.

 

Same here thats why I suggest checking for leaks while the car is running and hot

 

Almost always you can see the deposits left from a coolant leak of any significance. The residue is generally white with green or blue tinged crystals. Look all all joints, sensor locations, look at the radiator, etc. for small leaks. Usually if there is a leak it will happen at a plastic-aluminum joint or in the expansion tank. Note that although it's a closed system, over a very long period of time it isn't abnormal to see *some* level of coolant loss. If you top it up and it goes down quickly though you've got a problem to solve.

I'd bring it in though, if you haven't changed the coolant in a while, and have them swap coolant and pressure test the system. Coolant should be changed every two years I believe.

 

I had this last winter. I replaced the thermostat, a few hoses and the expansion tank and all was good again. A pressure test would show up the radiator if its that.

 

mine said the same thing the dealer just topped it off