Geo

I also got a coolant warning a few months ago (car was 10 months old). I filled it back to the normal level with water. It now seems like I can smell antifreeze by the front grill after driving the car. There is never any signs of liquid on the floor of the garage. Anyone else notice the same?

dillusiv

Coolant fluids are a closed system generally speaking correct?

IS there something uniquie about BMW coolant systems? I don't know why/how they could actually become low if it's a closed system.

Rudy

I'm no mechanic but generally speaking, most modern-day cooling systems have an expansion tank (sometimes referred to as the overflow tank) but are still considered a "closed" system. The expansion tank is connected to the overflow tube -- when the coolant (engine) gets hot, it expands. In the old days, the expansion of the coolant would cause it to flow into the overflow tube on onto the ground. Now, instead of spilling onto the ground, it flows into the expansion tank. When the coolant cools, a vacuum is created which sucks the coolant from the expansion tank back into the cooling system. In theory, since the system is closed, no coolant should ever be lost but sometimes you can be a little low. Adding coolant to the expansion tank (only when the system is cold) is pretty normal if you get a low-coolant warning once in a blue moon.

If you seem to get persistent low-coolant warnings, then you may have a small leak of some sort. If you smell coolant burning, that's another cause for concern. Usually, if you smell it, the coolant level is very low and likely overheated or you are leaking coolant and it is hitting another hot component like the exhaust manifold or the engine block itself...

katheikia

I had this happen to my E39 a few times, but not on my E60...Yet...15,000m..

zen

I believe that there are two marks on the dipstick. One for the level when the fluid is cold and the other when it is hot. Also there is air in suspension when the system is filled. When the air disappears the fluid level will be lower.

pinguhk

In HK they fill it with BMW coolant 100%, they do not use water
I know that the bottle say you can add water to it but they don`t
In HK it dose not get to 0 in winter, just about 5c

geokr1

You are a far more patient man than I to wait five hours. After many years of driving sports cars in Arizona heat, including Triumphs made for the cool UK, I have had to add water many times and never waited longer than 20 minutes or so. It's a bit dangerous but you can loosen the cap of most radiators with a towel to let off pressure without removing the cap - it's a safety feature that requires you to turn it past the first detent (pressure relief) to the second to take it off completely. When it's off I simply start the engine and add water slowly - it gets plenty hot enough before reaching the block to avoid "shocking" the engine. Recap the radiator, top off the reservoir and off you go. If you're in a hurry and near a water hose spray the radiator with cool water for a couple of minutes and you should relieve most of the pressure. Might sound redneck but it always works. By the way, "Coolant Low" means reservoir coolant, doesn't it? The engine ought to still have plenty. Just top off the reservoir. I don't know why BMW doesn't provide a temp gauge to verify actual coolant temps so that you'd know if there was a real problem or not.