c   c app  

DIY Radiator Flush

impee's DIY Radiator Flush / Coolant Drain for BMW 318i e46
How to Flush a Radiator / Coolant Drain yourself!

Difficulty Level: Easy

Approximate time for this project: 2 hours

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

Anti-freeze 1.5 Litre Part number: 83192211191 BMW 2 £10
De-Ionised Water 5 Litre (also known as Distilled water) 1 £4
Gasket Ring Part number: 07119963200 Part #8 BMW 1 £1
Flat Head Screwdriver     1  
Phillips Screwdriver     1  
Flat knife type tool     1  
Trolley Jack Should support up to 2 Tonnes. 1 £30
Jack Stands / Axle Stands Should support up to 2 Tonnes.
To lift car on stands, refer to this page. 2 £15
Oil / Coolant Drain Pan At least 5 Litre capacity.
1 £13


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! Some times 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 #16 of this DIY)
BMW 1 £2
17mm Screw Plug

Part number: 07119904539 Part #9
(please refer to section #14 of this DIY before you buy this)

BMW 1 £1
Radiator Cleaner 200ml Art no 0893 556 2
Use only if you wish to flush the radiator. 1 £7

*prices correct at time of publication

c   c




1) 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 litre each, however you only require about 2.5 litres of each to fill the Radiator.

Change Duration: The Radiator should be flushed every 2 years.

Kit for Radiator Flush


2) How It Looks

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.

BMW on Jack Stands


3) Radiator Cap Location

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

Radiator Cap & Vent Screw


4) Radiator Cap And Black Bleed Screw

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

Close up of Radiator Cap & Vent Screw


5) Engine Splash Shield

Next remove the engine splash shield.

This is the splash shield from underneath the car. This is to show where and how many screws and Expanding Rivets are located.
The Expanding Rivets are the top 3 and the remaining 7 are Quick-release screws.

Use the flat head screwdriver for the front Expanding Rivets and the philips head screwdriver for the Quick-release screws.

Car Sheild removed


6) 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 Quick-release screws.

Car Sheild half off


7) Shield Rivet - Removal

To remove the front 3 Expanding Rivets you need to first pry out the thin middle part all the way out, then you can pull the rest of the clip out.

Car Shield front Expanding Rivet


8) Splash Shield Expanding Rivet

This is a photo of the middle thin part of the Expanding Rivet pulled out and then the actual Expanding Rivet, removed.

Expanding Rivet

Expanding Rivets



9) Remove Radiator Cap

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

Radiator cap removed


10)  Radiator Drain Plug

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

Remove Radiator Drain Plug


11) Removing The Radiator 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.

Remove Radiator Drain Plug


12) Loosening The Expansion Tank Drain Plug

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

Loosening The Expansion Tank Drain Plug


13) Radiator - Draining

Demonstrating how the water & coolant mix pours out.

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

Water & Coolant pouring out


14) Loosening Engine Block Drain Plug

The engine Block screw drain plug also needs to be removed (and also the washer needs replacing) to drain all the water, but I do not have any photos of that yet and will put them up next time I am under the car. Apologies for that!

However have a look this photo that some one else has taken: photo. Once you are under the car and looking at the engine block - it is easily recognisable. You need to locate and open part #8 & #9 in this diagram.


15) 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


16) 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 happened to me!


17) Filling Ionised Water and Coolant

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 #19 and pour the required ratio of water to Coolant into the Radiator. This will be written on the Coolant bottle, depending on how cold climate you live in. For the UK (maximum -20 degrees) it is 1.5 litre of Collant to 3 litre of water, so to get the total correct, roughly about 1 full bottle of coolant + 250ml from the second bottle and 3.25 litres of water.


18) Radiator Full

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

Water level indicator in the Radiator


19) 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


20) 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 To pup 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.

BMW e46 Care Care e46 Models Fuse Box On Jack Stands Fault Diagnosis Torque Specifications Air Filter Change Alloy Repair Jack Stands CDV Delete Clutch Bleed Differential Oil Final Stage Resistor Fuel Filter Change Headlight Removal Interior Lights MAFS Clean Oil Change Oil Light Reset Power Steering Fluid Radiator Flush Radiator Fan Change Shiny Steering Wheel Spark Plug Change Transmission Fluid Window Regulator Timing Chain Tensioner Airbag Occupancy Mat Sensor Rear Light Clean BMW Fault Code Read impee impeeCreations BackInfo

DIY Radiator Flush / Coolant Drain by - impee

top of the page