Changing coolant reservoir

[marcva]

I need to change the reservoir on my E36. Do I need to drain the radiator? Or, do I just drain the reservoir and work fast?

Thanks,

Marc

[shadowpuck]

last time i've done this i just worked quickly.

[TostitoBandito]

The less messy way is to drain the radiator, yes. You're gonna have to add coolant and bleed it after regardless, so it's just a matter of needing more fresh coolant if you drain the radiator. Everything else is the same.

[bmwdirtracer]

I'd drain the radiator into a big drain pan, then drain the expansion tank as possible. Personally, I can't imagine how you're not going to dump pretty much all the coolant., except what might be held captive in the block. The E36 reservoir is pretty troublesome, to me, but maybe others know tricks which I don't....

[shadowpuck]

it's been a while since i've done this on my e36, but, i know the time i did it i did not drain the radiator. well, now that i think about it - maybe that was changing out the level sensor.....hmmm....

[TostitoBandito]

Draining the radiator is easy. Draining the engine block thankfully isn't really necessary for this unless you're doing the water pump or thermostat at the same time. The plug for the block typically requires the removal of one of the pre-cat O2 sensors in order to get at it, and then splashes all over the pipes.

[marcva]

K. I'll suck it up and drain the radiator. I figure rushing with fluid running out of the bottom line will likely lead to some awkward amateur oversight.

History is that I THOUGHT I had a bad sensor seal so I changed the sensor. very easy to drain the reservoir to do that with my mityvac... Then I noticed a pin hole in the reservoir itself...trip #2.

Yes, its factory
Yes its new (about a year old).

They just don't make them like they used to...sigh.


MP