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Any idea why coolant may be leaking from my expansion tank?

2.6K views 17 replies 6 participants last post by  DaggerPayne  
#1 ·
BMW 325i 2004 5 speed 2.5l.

I don't daily drive this car at all. I only use the car to go to the store about a mile away. If I were to daily drive that's what I got my other bimmer for.

I noticed the car started to overheat when I got off of a long drive on a 15 mile long bridge. I noticed my temperature gauge was in the red. I pulled over and popped the hood and noticed there was absolutely no coolant in the expansion tank; it all got leaked through what may be the many radiator hoses this car has. I thought that was the issue so I went to O'Reilys and replaced the expansion tank. The car still has an overheating issue and its still leaking from the many hoses the expansion tank is connected to. I bled the system multiple times and used the correct fluids. Even had my boy at the shop take a closer look at it. I don't see any signs of leaking coolant from the engine and the engine seems to have plenty of pressure when I cup it with the oil cap. I've provided some pictures of the obvious leaks, and they only leak from the coolant tank hoses! Engine seems pretty solid starts right up no problem I don't drive it at all just trying to figure out what may be the cooling issue.
1012073
1012074
 
#2 ·
- How many miles on the odometer?

- Do a compression test to r/o head gasket issues.

- Then search forum for cooling overhaul.

- Stay away from reservoir from OReilly etc. Stick to BMW or CoolXpert brand etc.
Info re brands (Conti belt, Wahler thermostat, Hepu WP, Sachs fan Clutch etc.) in those cooling overhaul threads.
 
#13 · (Edited)
Antifreeze color is caused by what ever dye the manufacturer uses and has nothing to do with compatibility. There was a chart of technically appropriate coolants available on NewTIS and that I had excerpted as fair use and copied here. BMW branded coolant blue and green can be mixed and some range of BMW's were loaded with green at the factory. Trust AND Verify!!!. YMMV

My X5 CPO had green coolant when I got it and the cooling system components all seem to be functioning well. The thermostat has been preemptively replaced twice at the BMW Service Center and the cooling system properly filled with coolant.

It's gonna be tough going back to first principles for all of these technical decisions absent NewTIS. I wonder how many Festers paid for their access and use. See ...

17 01 96 (140). Main group 17. Technically suitable antifreeze and corrosion inhibitor for BMW ... at NewTIS.info