Where does Coolant go? - BMW Forum

Delmarco · 03-05-2006, 01:07 PM

Okay, I can't find any leaks whatsoever.

1. The cooling & heating system in the cabin works fine.

2. Engine temp is fine (in NYC during the cold 20 degree to 30 degree weather the needle would dip to the cold side whiles driving over 50-60mph on highways).
3. I can't see where it would be leaking out under the car. All hoses (as far as I can see) under the hood are intact and good condition.

Yet every week or after about 500 to 1000 miles of driving my coolant level is about 25% to %40 less than it was.

I did have a scare last winter when I saw blue/green liquid dribbled into the cabin footwell. Everyone who saw the pics conceded that it was washer fluid, and not coolant since my heater core would have exploded for coolant to be leaking there. And had the core exploded I would have been plagued by a sleu of other problems and coolant would have been gushing out non-stop and not dribbled and dried up.

Where is my coolant going?

4evrwyntr · 03-05-2006, 01:16 PM

It's been cold recently. Tighten up the hose clamps.

tomctx · 03-05-2006, 03:12 PM

Take it to a garage and have it pressure tested. They can put a dye in and find where the leak is coming from if it's not obvious.

walshja · 03-05-2006, 06:42 PM

you could just have air in your system, and essentially what you are doing is bleeding the air out of the system over the course of weeks, by adding a little every time.

if you are not smelling any coolant, or seeing any puddles of coolant under your car, my guess would be that you are simply bleeding your system over time.

97alpineM3 · 03-05-2006, 08:04 PM

Are you smelling coolant when you first turn on your heater?...

Common sign of coolant in the footwell is a leak on the imput line of your heater core. Only reason I say this.. is cause sometimes once it leaks a lot... seals it self with the dried coolant.. which leaves a powdery chalk... and now you might have a small leak.. poke around.. you might find it...

Is your oil still dark.. no milky ness?...

You might be slowly burning it... a leak.. next to a extremely hot spot.. will often evaporate the fluid faster than a drip. Which is called a pressure leak. Doesnt leak with no pressure on the system.

Have your coolant system pressure checked.

Peace,

Les

Redbullrr · 03-06-2006, 09:29 AM

I would test it for compression. Same thing was happening to me, it turned out to be a HeadGasket.

green325is · 03-06-2006, 04:13 PM

I don't think I have a headgasket issue, and recently (past 10k miles) replaced the cooling system (radiator, hoses, expansion tank). Before and after I have always smelled coolant when turning the heater on and my car will need about 1/4 cup of coolant once a month (maybe less). I once heared from BMW "well BMW's will use some oil and will use some coolant." Thats BS, a car shouldn't "loose" coolant under normal driving conditions. I must have a small leak somewhere.

walshja · 03-06-2006, 04:25 PM

if you are smelling coolant when operating the heater, you probably have a bad heater core.

mine went last winter, and I was smelling coolant for about a year before I finally fixed it.

started off exactly as you are describing, then finally started leaking real bad.

i never saw coolant leaking into the cabin, in fact I never saw any coolant leaking anywhere. I just smelled it, and finally it started fogging my windows up so bad I had to get it fixed.

replacing your heater core is not an easy job, I would keep adding coolant until the problem gets worse.

k2c69n · 03-06-2006, 05:03 PM

What type of coolant do BMW's use.. I have to add some coolant to mine, it is telling me my coolant is low.. what kind should i pick up?

green325is · 03-06-2006, 05:50 PM

Ideally you want to use BMW coolant, but if you don't have BMW coolant in there now try to add to whatever is in there with the same stuff.

walshja,
What kinda of price are we talking about re: replacing a heater core? Did you have it done @ a dealer or independant shop?

walshja · 03-06-2006, 06:38 PM

green325is, i went to an independant mechanic, although the price between the dealer and independant mechanic was not that great.

the heater core total price was something like $1200. the rest of my cooling system was OK.

replacing your heater core involves removing the passenger side of your dashboard, from what I have researched not a job for the faint of heart.

you having problems with your heater core?

green325is · 03-07-2006, 03:42 PM

Quote:

Originally Posted by walshja

green325is, i went to an independant mechanic, although the price between the dealer and independant mechanic was not that great.

the heater core total price was something like $1200. the rest of my cooling system was OK.

replacing your heater core involves removing the passenger side of your dashboard, from what I have researched not a job for the faint of heart.

you having problems with your heater core?

My heater seems ok, although at times when set at "72" the air can go cold and I need to bump the dial up to get the heat back. And yea I do smell coolant sometimes with the heater on! And since you mentioned the issue with the fogging of the windshield, I have started to notice it more. Hopefully it can hold out for 3 or 4 years until I get another car, I hate to dump that much $$ into a dam heater core. The engine or clutch I don't mind spending money on though. Funny...

tomctx · 03-07-2006, 07:07 PM

It's not so much the heater core as it is the labor to replace it. Like Walshja, a bear to replace. And then you get to BLEED the system again! Joy! OH! Joy!

walshja · 03-08-2006, 08:13 AM

I fought fixing mine for over a year, then last winter it got so bad that I could not use the heat at all.

If I did turn the heat on, even for 1 second, the entire car would fog up INSTANTLY.

It was actually very dangerous, cause once it fogged up, there was no way to get rid of it, except to shut the car off, and let everything dry up.

It was kinda funny, I would get out of work, and the temperature would be around 20 degrees. I would promise myself that I would NOT turn the heater on. So about 15 minutes into my 1 hour commute home I would literally be freezing my ass off, and I would talk myself into turning the heater on for just a second, just to warm my hands up. Well, instantly all the windows in my car would fog up, and I don't mean a nice little haze on the windows, but the antifreeze would put this slime on the windows that wouldn't even let you wipe it off, it would just smudge. I would have to then open up my windows, in 20 degree weather and drive with my head out the window until the windshield would clear up to where I could close my windows. By this time I am simply frozen to the core !!! Don't wait that long before fixing your heater core !!!

Ohh, and because of the heater core leak, I got air in my cooling system, and the car started overheating.

It is an expensive and crappy job, but sadly, you will be forced to fix it.

Then when you do get it fixed, it's like you are driving a brand new car !!!

good luck man !!

walshja · 03-08-2006, 08:16 AM

ohh, TomCTX is right, the heater core itself was maybe $200, the rest was all labor !!!

also, you can pinch off the lines to the heater core, disconnecting your heating system from the cars cooling system, if you are short on cash and live in a warm climate . . .