BMW E46 Fanatics Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
2002 325i

Just got this car. Coolant was low in the expansion tank. I filled it up, ran the car with heater. Filled it up again. When I stopped the second time, there was coolant steaming/spitting out of the top of the connection where the upper radiator hose connects to the radiator and the expansion tank was empty.

When I filled the expansion tank this time, coolant started pouring out of that (bottom) of the upper radiator hose connection. The hose connector at the top of the radiator was backed off about ¼ inch. From the forums, it looks like I need a new hose that is tight. This one is not. So, I’ll get one of those.

I took the hose off completely and tried to run water through the radiator to see if it would come out the engine. The radiator would not take any water from a garden hose.

I put the hose in the expansion tank. Water/coolant started pouring out of the engine where the upper radiator hose would be. Tried the radiator again. Wouldn’t take anything. Expansion tank again, water flowed right away. I put the hose back on, filled the expansion tank. Same thing. Water pouring out the top connector.

There was minor sediment build-up on the outside of the radiator at the connector. Minor abrasions. Felt around in the radiator with my finger and it felt dirty…like some random deposits/caked here and there.

I am getting the radiator fill light periodically but not consistently but the temp gauge never gets above halfway. Periodic but inconsistent interior heat from heater. Seems like the radiator is blocked and it won’t let coolant in. Doesn't seem like a flush would do any good if nothing is getting into the radiator. Am I missing something obvious? Is the next step a new radiator (besides the upper radiator hose)? I’ve worked on my Hondas for 20 years and am comfortable with them but I don’t know much about BMW.
 

·
Registered
Joined
·
2,377 Posts

·
Registered
Joined
·
148 Posts
Definitely replace the expansion tank... from reading around here, it's pretty much enemy #1 and the single part that is most prone to failure. Mine somehow went 125k without exploding, but as soon as I saw it was original I replaced it the very next week (along with the entire cooling system). I plan on replacing the whole cooling system every 50k-75k, which is basically every 5 years.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #4
Thanks swordsman. I didn't see anything there to address this specific issue but I will repost over there.
 

·
Registered
Joined
·
227 Posts
Most people will tell you to replace the entire cooling system in one shot. I got a behr radiator for a little over $100 and it seems to work great. Most non oe style radiators will not line up right with expansion tank mounting bracket.
 
1 - 6 of 6 Posts
Top