BROWN SLUDGE EXPANSION TANK

[G-Man]

Hi All
New Kid on the block, I have a 318i touring and picked up a problem on Sunday where the expansion tank was full of brown sludge. The temp is normal and no other alerts. Question: what caused this and how do I correct it.

Thank you <.< G-Man

 

[Spy007]

No Idea but I did replace the expansion tank on gopher and there is a diy so if that helps.

 

[Sith]

It's rust in your cooling system, and it's caused by not changing the coolant regularly. As it's causing you no problems, the cure is simply to flush the system and put in new coolant. If there are any weak points in the system, the flush may cause them to show up, and you may need one or two small repairs. However, that is better than waiting for the weak points to cause overheating and, in turn, bigger bills. Make sure you use BMW coolant.

 

[Die_Miek]

+1 on rust in your cooling system.

i had the same problem on my wifes tazz.
here's how i rectified the problem:

1. i bought radiator flush too loosen all the crap. added the radiator flush as per instructions on the bottle
2. i than drained all the water out of radiator.
3. i refilled the radiator with clean tap water, and loosened the pipe that returns the water from the engine to the radiator.
4. i than started the car and while idling i fed clean water into the radiator with the hosepipe until there was only clean water coming from the engine.
5. i drained the tap water from the radiator,connected the pipes and added distilled water and antifreeze

note: this was on a tazz, if you have some DIY skills and shouldn't be too difficult on a BMW.

cheers

 

[Diablo Jnr]

Flush your system as suggested, but if it doesn't solve your problem, have your mech check your engine oil cooler, its a common problem with your model car. If its the oil cooler, your mech might be able to by-pass the oil cooler, which is the cheapest solution, if not, its going to be a pricy repair.
Hope you just require a flush :thumbs: