How do I know if I need to add coolent?

[EDG08]

So every 5th time i start the x5 is says to check coolent level. So today i checked it and the resevore is about 1/4 full. The red bobber is about an inch below the top. I am going to get the oil changed in the next month or two and am wondering if i should just have the dealer change the coolent with the oil? In the meantime should I top it off the coolent? If so what kind should I use and how much should i put in?
Thanks guys
2002 4.6is

[chefwong]

You have a leak possibly. Eyeball the engine and check 1st along the expansion tank area. If not, look around the hoses and see if there a buildup of coolant somewhere...

Have you ever topped it off. If so, how long before it went below the line. You want the round part of the stick to be level with the top of the reservoir. Reminder to user OEM coolant or compatible coolant with distilled water.

I did my valley pan about 4 months ago. Do a search on ~valley pan~.

When the coolant goes, it goes out quick so plan accordingly and

[EDG08]

So what type of coolent should I use? Or should I just wait till i get it changed at the dealer? I am below the min level but i know that there is still about an inch in the reserve tank.
thanks

[chefwong]

my point was that I don't think u need antifreeze flush. My hunch is on a coolant leak that you need to identify and address...

[Weasel]

If the coolant has never been flushed whether it be an actual flush or a system component failure like a waterpump etc that would have lost coolant during replacement, it should be done... It is recommended to be done every 4 years to keep the coolant fresh and acting right. I did mine last year.

You can top it off with water and keep an eye on it until the oil change is due, then have it checked out for leaks and serviced.

[m5james]

Check for coolAnt (notice the A, not E in coolAnt) leaks that look like white streaks running down things. It's a sealed and pressurized system, so it's going somewhere. If it's something you can't see directly from looking around the engine bay (coolAnt resevoir, radiator connections, expansion tank, heater diverter valve) then it's most likely the valley pan.

As for the coolAnt type, you can use either BMW brand (more $) or Zerex G-05 (less $). It has to be phosphate free, and I wouldn't personally trust all those "Works in all makes/models" coolAnt as they must have made cuts somewhere in order to be able to state those claims.

[bgsquad]

But the warning should not come with the level he describes in the reservoir... the guy is only one inch low! I had once the reservoir totally empty (maybe a little down there) and still i had no coolant level warning... I would suspect a faulty sensor, especially that the warning comes and goes while the level is constant (assuming on a leveled surface)

Now about the missing inch, it might very well be normal as many threads talked about the unidentified missing coolant or something I myself miss around 300ml to 400ml every 6 months or so, with no leaks under pressure test... the last time i topped up with water, when it's time for the next top up i'll do it with antifreeze (to keep the 50/50 ratio)...

[omodos]

Yup mystery coolant leak issue, mine is a diesel so pan valley doesnt apply I have been told, but up to now i to up say half a bug full every 1000miles and dont wait for my sensor to tell me, as for coolant i use bmw 50/50 mix or 60 water 40 coolant...

[EDG08]

I put about 8 cups of water in the resivour to fill it up that should get me a month untill i get my oil changed. Putting water in wont hurt anything right? I guess it is duluted with the remaining coolent in the engine.
Thanks guys

[roadfrog]

I researched Zerex G05 and as a result, used it for my rad flush and coolant replacement. Silicate, Amine and phosphate free, just like BMW requires.