Interesting Coolant Leak - BMW Forum

reepicheep_85 · 06-14-2007, 06:04 PM

So, I have been dealing with a coolant leak on my 92' 325is for awhile now and still don't have a solid idea where the leak is. It appears that the coolant is leaking out near the tranny. Are there any coolant lines that run to the tranny? This all started when it randomly overheated on me while I was heading to work. I have since replaced the entire cooling system (thermostat, alum. t-stat housing, radiator, metal impeller water pump, converted to elec. fan, all new gaskets and bled the system properly) My first theory was that the engine had overheated so badly that it had pushed the coolant through the seals somewhere because it only leaks when the car gets hot. Anyone have any ideas? Has this ever happened to anyone? I've searched all over and can't come up with a viable answer. Any help is much appreciated.

Starmavin · 06-14-2007, 08:50 PM

Was your coolant rusty color?

reepicheep_85 · 06-14-2007, 08:54 PM

Not at first. When I re-filled and let it warm up I just used water (didn't see the point in wasting coolant if it's just gonna leak out) and it is coming out slightly rusty looking. I've never seen a car do that before, what does it mean?

Starmavin · 06-15-2007, 09:23 PM

It could mean internal corrosion, if it's not then don't worry about it. Can you smell coolant with your heat on?

SHAHAB323IS · 06-16-2007, 10:15 PM

if it looks like it's leaking by the tranny, it's most likely a leak in your heater core, it can be hard to determine because it will leak onto the top of the transmission and at times you won't be able to see a leak, best bet would be to take it to a shop and have them pressure test it, they will be able to determine where the leak is coming from and you can take it from there

reepicheep_85 · 06-17-2007, 01:27 AM

Quote:

Originally Posted by Starmavin

It could mean internal corrosion, if it's not then don't worry about it. Can you smell coolant with your heat on?

yeah, I can actually smell some coolant when it's on. Are there any coolant lines that go to the tranny itself? It seems like there are, but I'm having a hard time routing them.

Starmavin · 06-17-2007, 10:46 AM

No the trans fluid goes to the rad not the other way around. Thats why I was asking if you could smell coolant, you heater core could be leaking.

reepicheep_85 · 06-17-2007, 03:12 PM

Ok, Thanks for the help I will check it out today.

reepicheep_85 · 06-17-2007, 05:06 PM

So it does appear that the leak is coming from above the tranny. Would the problem be with the heater core itself or with the lines that connect to the core? In the past when I have replaced heater cores, it has been because of a puddle on the floor boards, why would it be leaking outside but not in?

Starmavin · 06-18-2007, 12:22 AM

It could be leaking from the hose and running down the firewall. Or it could be worse.

reepicheep_85 · 06-18-2007, 11:27 AM

I pulled the dash apart last night and got to the heater core. It is definetly leaking and it looks like there is a drain hose that lets all of the coolant that has leaked out of the core itself drain through the floorboard. I'm hoping that is the problem since I just spent an entire day tearing that damn thing apart.