Z4M: 50K Mile Coolant Flush

After reading through Ron's post below to get a idea of how to go about draining the block neatly, I started the coolant flush process this past weekend.

http://www.bimmerfest.com/forums/sho...=coolant+drain

After thinking through and analyzing the tight area for draining, I decided to make a flexible funnel that will allow drip style draining to a container under the car. Below are some pics of the coolant drain process -

The flexible funnel made from Reynolds silver foil, duct tape and the base of a funnel nozzle. Then attached a flexible hose to it.





Drained the radiator first - I loosened the blue plastic bolt with a flat head screwdriver enough to get a smooth stream of coolant flowing out with splashing all over the place.






Got about 3.5L from the radiator


Coolant looked quite clean for 53K miles


Next up was the block drain. Loosen the exhaust header heat shield to create space to get your hand and a ratchet in there. I put some silver foil over the nitrogen canister and around that area just incase there was an "accident" with the drain bolt. Then I positioned the flexible funnel under the drain bolt and routed the hose to under the car to a catch pan. Then broke the 13mm bolt loose and unscrewed it slowly to a point where the coolant started to drip out.







About 10-12 hours later - about 3.8L or so (a little over a gallon)


About 7.6-7.7L of coolant drained - neatly


I ordered up a new drain bolt and washer for the block and a spare for the radiator (could not find a P# for the washer on the blue plastic plug).





More to come when I get the new bolt and washer and start the refill process.

Originally Posted by pal

After thinking through and analyzing the tight area for draining, I decided to make a flexible funnel that will allow drip style draining to a container under the car. Below are some pics of the coolant drain process -

The flexible funnel made from Reynolds silver foil, duct tape and the base of a funnel nozzle. Then attached a flexible hose to it.

That works.

Griot's has one:

http://www.griotsgarage.com/product/...rrivals&page=1

Great writeup!!!

The new plugs (block and radiator) came in today from North Haven so I picked up some Distilled Water from the local CVS and completed the refill.

You only need the radiator plug (blue with washer), gasket ring and block drain plugs. The adjusting plates are just me replenishing my shim kit ...




Antifreeze and friends.


The car took almost the entire 7+ litres without needing a restart. You need to loosen the 2 bleed screws a couple of turns to let the air out (you will hear a little whoosh) until you start seeing coolant seep from the screws. The fluid in the reservoir bubbles to let air out and the surface is full of minute air bubbles.








Start the motor up, turn the heat and fan to max and let it idle until you feel the coolant hose coming off the thermostat get hot (thermostat opens). If you see the coolant level in the resorvoir rise, just turn the bleed screw on the reservoir a couple of turns to let the air out.


That's it. I think I am done - leaving the car to sit overnight and will take it for a spin tomorrow to ensure no leaks and proper level.