DIY Radiator Flush

impee's DIY Radiator Flush / Coolant Drain for BMW 318i e46
How to Flush a Radiator / Coolant Drain yourself!
Taken from: http://www.impee.co.uk/radiator_flush.htm



Prices: Professional labor costs for Radiator Flush / Coolant Drain  - 55 (private) or 155 (BMW) - per hour X 1 hours

Please Note: Tools required below will also be useful for other DIYs

Difficulty Level: Easy

Approximate time for this project: 2 hours











5 Liter, Anti Freeze & Summer Coolant




Ionized Water

5 Liter (also sometimes called Distilled water)




Flat Head Screwdriver





Phillips Screwdriver





Flat knife type tool





Trolley Jack

Should support up to 2 Tones.




Jack Stands / Axle Stands

Should support up to 2 Tones.
To lift car on stands, refer to this page.




Oil / Coolant Drain Pan

At least 5 Liter capacity.






It is a good idea to go and buy an extra Vent Screw from BMW before you start the DIY. Past DIYs (and my impatient nature) have taught me to always have at least 1 extra of each screw, bolt or clip! Sometimes you could simply loose one, break or even strip it! They only cost from 0.70 up to 3.00 a piece, depending on what you buy.






Vent Screw

Part number: 11537793373 Part #2.
(please refer to section #17 of this DIY)




Radiator Cleaner 200ml

Art no 0893 556 2
Use only if you wish to flush the radiator.















Assemble Your Kit + Notes



Below is the total kit I used. As you can see, there aren't many tools required for this job at all. The bottles are 5 liter each, however you only require about 2.5 liters of each to fill the Radiator.

Change Duration: The Radiator should be flushed no sooner than every 2 years.





 for Radiator Flush




How It Looks



Best for it to be on 2 stands, so all the water can drain.

Having the car on Axle / Jack stands is optional. I used it as I could not get the screw driver underneath the car to open the splash shield screws. If you have a short Philips screw driver, then you should be able to get away with no Axle / Jack stands.

For more details on lifting the car on Jack Stands, please refer to this page.





on Jack Stands




Radiator Cap Location



Just to show the location of the radiator cap and bleed / vent screw.





Radiator Cap & Vent Screw





Radiator Cap And Black Bleed Screw




Close up of the Radiator cap and the bleed / vent screw.







Close up of Radiator Cap & Vent Screw




Engine Splash Shield



This is the splash shield from underneath the car. This is to show where and how many screws and clips / Expanding Rivets are located.
The Expanding Rivet are the top 3 and the remaining are screws.





Sheild removed





Splash Shield Being Removed




Splash Shield in the process of being removed, using the flat head screwdriver for the front Expanding Rivets and the Philips head screwdriver for the remaining screws.







Car Sheild half off





Shield Clip - Removal




The front 3 Expanding Rivets are a little odd. You need to first pull out the tin middle part all the way out, then you can pull the rest of the clip out.







Car Shield
 front Expanding Rivet




Splash Shield Expanding Rivet



This is a photo of the middle thin part of the Expanding Rivet pulled out.










Shield Expanding Rivet Removed




This is the actual Expanding Rivet, removed.












Remove Radiator Cap




To begin the process or draining the radiator, first open the Radiator cap.







Radiator cap removed





Remove Big Blue Drain Plug



Next get underneath the engine / car where the splash shield was removed and locate the big blue drain plug.





Radiator plugs



How to Remove Blue Drain Plug


Open and remove this drain plug with a similar tool or flat head screw driver and watch for the water that starts pouring out immediately. Also make sure the drain plug does not get lost.



Opening the big radiator plug



Loosening The Smaller Blue Drain Plug


Only loosen this second smaller blue drain plug (turn it a couple of times round with a flat head screw driver) and let the remaining water drip out.



Opening the big radiator plug



Radiator - Draining


Demonstrating how the water & coolant mix pours out.

NOTE: Coolant is poisonous, if any leaks on to the ground, wash it away with water. As it is sweet, animals tend to drink / lick it.



Water & Coolant pouring out



Radiator Bleeding


Now to bleed the radiator to enable all the water to come out, turn the black bleed / vent screw a few times to loosen it, with a flat head screw driver.



Opening the Bleed / Vent screw



Radiator - Flushing


Next fit the big blue drain plug back and also the smaller blue drain plug (but not too tight, as you may damage them) and fill the radiator with water. I used tap water myself, but if you prefer, you could use distilled water.

Next close the radiator cap and tighten the black bleed / vent screw and either take the car for a short drive or start the engine and rev it a for a few minutes. This will enable the water to mix with / dilute any remaining old coolant.

NOTE: Do not over tighten the bleed / vent screw, it will / can break in half...as happened to me!



Filling water in the Radiator



Filling Ionized Water


Make sure the radiator isn't too hot, then slowly open the Radiator cap again (with your face pointing in the other direction), open and remove the big bottom blue drain plug again, loosen the smaller blue drain plug and then loosen the top bleed / vent screw again. Then wait for all the water to drain out, it may take about 10 minutes.

Next close and tighten the bottom blue drain plugs (not too tight).

Turn the heating on full in the car as in Step 21 and pour about 2.5 liters of water into the radiator.



Filling Ionised water in the Radiator







18) Filling Coolant

Next pour about 2.5 liters of Coolant into the Radiator



Filing Coolant in the Radiator





19) Radiator Full

Pour until the orange stick sticks out as below, indicating it is full.


Water level indicator in the Radiator




20) Heating On Full


Close the Radiator cap and tighten the black bleed / vent screw next to it.
Now turn on the engine and rev it for about 5 minutes, also turn on the car heating to full temperature. All these will bring out any air trapped in the pipes.



Heating Control System in the Bimmer





21) Radiator - Bleeding

One you have done that, leave the engine running and open the Radiator cap and loosen the black bleed / vent screw until water starts coming out of the hole.
This process gets rid of the trapped air. Now you may need to pour a little more water / coolant in the Radiator again, to fill it up.
Follow this procedure as many times as you like, while revving the car.

Once satisfied, fix the splash shield back to the bottom of the car, tighten the Radiator cap and tighten the bleed / vent screw (again not too tight).

One method to tell if all the trapped air has been released is to ensure you are getting constant hot air from your air vents inside the car.
If it fluctuates, it means there is more to bleed



Bleeding the Radiator




21) Final Top off Water & Coolant


Once the car has completely cooled down, open the radiator cap once again and top up the radiator with water & coolant (till the yellow stick sticks out again), as it will usually be required.







DIY Radiator Flush / Coolant Drain by - imran hamid www.impee.co.uk