Where is the coolant going?

[Jay 535i]

I have the infamous heater core problem, and my coolant level needs topping up from time to time.

I realize that coolant is getting on/in the heater core, but then where does it go? I'm not really familliar with all the ins and outs of the cooling system and the heater core. When my coolant level goes down, where did the coolant go?

[E34-520iSE]

If your heater core has a leak, then your coolant will be running down from deep behind the dashboard, down the carpet an onto the front footwell metalwork. You may be able to smell coolant too.

HTH,

Shaun

[Jay 535i]

I don't detect any coolant inside the interior. That's my biggest fear. Is there CERTAIN to be coolant on carpets, etc.?

[av8r]

if your expansion tank is mounted to the firewall i would start there. I had a small crack in mine and would loose a little collant over time. New tank, no more coolant leak. Another way to tell if your tank is leaking is to remove it and look on top of the bell housing. if you see tell tale signs then i would assume its the tank. The tanks are prone to develope cracks on the back side of the tank.

[Akhil]

I was loosing coolant only when my heater is ON. So today when I mover my car out of parking lot I saw some fluid on floor under the engine bay. I opened hood and checked while engine is running and heater set to full hot. I found some wet spot under intake mainfold. Got a flash liget and zoomed it on different spot under intake mailfold and find coolant seeping from a tiny crack about an inch away from the clamp which connects hose # 7 to engine block. So I think I need to replace hose # 7 ( 4-way hose). But until then I am planing to turn OFF heater (set to min). But I am not sure turning heater off will make leak stop or not. Any idea?

http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=11_1123&hg=11&fg=35

You might wanna check under intake mainfold for any leak related to heater before you go for extensive check in heater core ect.

Thanks
Akhil

[Traian]

What makes your think it's the heater core? Coolant leak may be a number of things. Are you sure it's not pooling somewhere inside the engine bay?

[Paul in NZ]

isnt there a tray under the heater core that drains to the outside?

[Alan_525i]

Yes there is. If the core is leaking it drips down to the "box" that its in (for lack of a better word). There is a drain tube there that goes to the outside. This is there also to prevent condensation from building up in that area. You can put the car on ramps, find the hole and stick your finger in. It will be obvious if its coolant or not. You can even take a small taste (be careful, it is poisonous) if you aren't sure.