e39 get hot and leak top of coolant reservoir

[bunty83]

hello
i got 1997 528i 5speed m/t . for some reason when i drive in city coolant start leaking top of coolant reservoir. already change the coolant reservoir cap. but still leak and temp gauge get high. but when i drive on freeway it is alright. no leak .
plz help.

[maardein]

Did you bleed the cooling system, and check for air in the system?

You should check you fan clutch as well.

[mattmartindrift]

probably the reservoir itself is bad. diagnose and replace.

[cnn]

You need to do this whole thing ASAP:
www.bimmerboard.com/forums/posts/199986 (http://www.bimmerboard.com/forums/posts/199986)

[540i nashville]

:rofl

...welcome to BMW ownership- now go replace your entire cooling system.

[jamesdc4]

Welcome to BF.c.

If your coolant reservoir is leaking in the city, it's a good bet that it's also leaking on the highway. At the higher speeds, it's likely that the extra volume of air being pushed through the engine compartment is keeping the engine from overheating. Make no mistake about it. You are looking at a huge expense in repairs if you continue driving the car in this condition. Do as cnn mentions and do a complete cooling system overhaul. If you or the PO have already replaced parts of the cooling system, then replace everything that got neglected including the expansion tank.
A blown head gasket or worse could be the result if you put this off.

Good luck.