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DIY: How to change the coolant?

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140K views 6 replies 6 participants last post by  drozd  
#1 ·
Hi guys can anyone tell me how to change the radiator coolant? The reason for asking is because I can't find the drain plug at the bottom of the radiator.
 
#2 · (Edited)
sorry I got it.

Ok, the following is from the BMW Technical Information System, 1982-2004, v 6.3.1.23B, and addresses the Series R53, engine W11 Cooper S. Call that my disclaimer, neither BMW nor myself is responsible, etc, etc. You will need the vehicle on ramps or a similar safe elevation device.
1) Carry out the work on the cooling system after cool down
2) Properly dispose of the coolant per local regulations
3) Before ignition off, place the heater control in HIGH HEAT and the fan on LOW
4) Remove the pressure relief cap on the expansion tank
5) Remove the under body protection panel
6) Disconnect the lower radiator hose, drain and catch the coolant. You will get wet.
7) When it stops flowing, reconnect the hose
8) This part is hard to describe but...behind and below the intercooler, under the wiring bundle, is the heating distribution pipe. This is a small, 1" or so, rubber hose. You can see it when looking down over the back of the intercooler. There is a small 6 pt bolt head, looks shiney, cadnium plated or such, screwed into a fitting in the heater hose. This is a VENT plug and must now be RELEASED (loosened).
9) RELEASE the vent plug in the UPPER hose. This is visible at the top of the radiator, this plug is slotted for a screw driver and is also fitted to a port clamped into the hose. Leave BOTH plugs loose as the system is vented during filling.
10) Using proper type and mixed coolant, pour the coolant into the expansion tank. As the coolant emerges from the vent plugs, tighten them.
11) Fill the expansion tank to the MAXIMUM indication line.
12) Start the engine and allow to run at idle, adding coolant if the level drops.
13) Continue running the engine until the coolant stops dropping, switch off the engine and top off if necessary. FLUSH all surfaces with water when finished.
 
#4 · (Edited)
MINI Cooper S

MINI Cooper S R53 AntiFreeze Coolant Flush

The following procedure flushes the cooling system and replaces the defective plastic coolant expansion tank with a superior metal tank.
The R53 coolant capacity is 6.0 L (6.3 qts) with the tank filled to MAX, and this procedure removes ~6 qts.
Duration is a few hours, including the messy clean up.

References:
MINI Owner's Workshop Manual - Haynes
http://www.mini2.com/forum/first-generation-mini-cooper-s/176299-diy-how-change-coolant.html
MINI COOPER :: North American Motoring - Coolant Flush DIY?
MotoringFile MINI R50/R53 Buyers Guide (coolant tank problems)


Parts:
BMW/MINI coolant, 1 gal
Coolant Type:
One Gallon BMW Part# 81 22 9 407 454
82 14 0 031 133
82 14 1 467 704 (found this one at BMW dealer)
(note BMW coolant is the same blue color coolant as MINI's)
Distilled water, 6 gal
Funnel that tightly fits on the BMW coolant container top
Catch container (large rectangular plastic storage type with 6" deep sides and cover, Wal-Mart ~$12)
Locking pliers for hose spring clips
Wetvac, 4.5 HP minimum (Stanley from Wal-Mart ~$50)
Wetvac tapered adapter (1 1/4" down to 1/4" dia) Tip: ShopVac brand hoses seem to leak more. If the unit only has 2 1/2" hoses, then a 1 1/4" adapter is needed.
Forge Motorsport Aluminum Coolant Tank, optional ($180, Forge Motorsport - Way Motor Works)


1) While car is running, turn heater on HI and fan speed to Low setting.
2) Park with front-end up on ramps and in reach of an electrical outlet.
3) Turn off and wait until the engine has cooled down; prepare wetvac, tools, etc.
4) Very slowly remove the pressure relief cap on the coolant expansion tank.
5) Remove the under body protection panel and move catch container into position under the lower radiator hose.
6) Wearing safety goggles/gloves/mask, very carefully disconnect the lower radiator hose, drain and catch the coolant.
7) Connect wetvac 1 1/4" end on lower radiator hose and turn on wetvac to draw remaining coolant from water/coolant pump and engine block.
Note, it's a tight fit and requires shoving the wetvac 1 1/4" end up into the lower radiator hose end until a watertight fit.
8) Turn off wetvac. Disconnect the upper radiator hose at the point right after the vent plug (in the direction from the radiator towards the engine).
Tip: The dull flathead screwdriver used for the vent plug, can be used to gently pry the hose loose from vent plug housing.
Do NOT push the tip under the hose end, just use gentle sideways force around the hose end to separate them a bit, then pull the hose off.
9) Turn on wetvac to remove additional coolant drained from upper hose removal/message, then turn off and disconnect wetvac from lower radiator hose.
10) Disconnect the lower and upper hoses of the coolant expansion tank (should be empty). Remove the plastic tank if later replacing with metal Motorsport tank.
11) Completely drain the wetvac by pouring into the catch container (then pour all used coolant into an empty 1 gal container if keeping track of how much coolant removed).
12) Use the wetvac adapter and funnel on upper radiator hose to pour distilled water, flushing the radiator until only clear water drains (~2 gal).
13) Pour a funnel full amount of distilled water into the other upper radiator hose in the direction towards the engine (cleans hose with very slow drain).
14) Reconnect original upper radiator hose.
15) Pour distilled water into the lower coolant expansion tank hose, using wetvac adapter/funnel.
16) Repeat step 15 until drained water appears clear (~1 gal).
17) Reconnect wetvac to lower radiator hose and turn on wetvac.
18) Repeat step 15 until distilled water is removed, flushing the engine block/water pump as much as possible (~2 gal).
19) When all the coolant/water mixture is believed to be flushed, then repeat step 11 to compare the most recent old coolant/water mixture with a new 1 gal distilled water container.
Tip: They should appear similar, but not identical as the drained water may have a sleight off-clear discoloration, indicating when the cooling system is flushed.
20) Reconnect all original hoses. Install the new metal tank.
Tips: Do not install the lower plastic guides on the new tank until it's fully in place and connected.
Remove the #3 spark plug wire from the coil for more room.
Carefully lower the new tank downwards, avoiding contact with any metal surfaces as it's easily scratched.
Rotate it around to connect the two hoses and attach the top bolt. Insert and finger tighten the lower passenger side plastic guide on the bottom bracket.
21) Open the heater hose vent plug. Behind and below the intercooler, under the wiring bundle, is the heating distribution pipe. This is a small, 1" or so, rubber hose. You can see it when looking down over the back of the intercooler. There is a small 6 pt bolt head, looks shiney, cadnium plated or maybe gold colored, screwed into a fitting in the heater hose. May require a foot long extension to reach. This is a vent plug and should be opened (loosened).
22) Open the vent plug in the upper radiator hose. This is visible at the top of the radiator and slotted for a screw driver and is also fitted to a port clamped into the hose.
23) Leave the vent plugs open (but don't remove them) so the system is vented during filling.
24) Using proper type and mixed coolant, pour the coolant into the expansion tank. If coolant emerges from the vent plugs, tighten them (don't overtighten).
25) Fill the expansion tank to the MAX indication line and close the vent plugs.
26) Start the engine, turn the heater on HI and allow to idle until the temperature gauge rises towards halfway, adding coolant if the level drops.
27) Switch off and slowly open the vent plugs to vent air and see if coolant escapes. Close the vent plugs.
28) Repeat steps 26-27, until no air hisses out and coolant emerges.
29) Install the pressure relief cap on the coolant expansion tank and allow the engine to cool.
30) Clean up all equipment and flush all surfaces with water.
31) Check coolant level and top off as necessary.
32) Properly dispose of all used coolant mixtures (note AutoZone won't take it).