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How It Works
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Why Change your Engine Coolant?
Antifreeze does more than extend the freezing and boiling point of the engine coolant,
it lubricates the water pump and provides corrosion protection for the aluminum radiator
and engine components. The cooling system should be drained and replenished with new
coolant every two years. If a regular schedule is kept, the additional
trouble of a system flush is not necessary as minimal deposits will accumulate.
How To Do The Job
Allow two hours for this moderately-difficult job. On the M60 engine it is essential
to use the three drain plugs provided to effectively remove the existing coolant.
You will need to raise the front of the car at least eight inches such that you can safely
work underneath. Do not rely on jackstands, ramps are much safer (or in a pinch, a
street curb.) The radiator has a drain plug on the left tank and the engine block
has a plug on each side. All are 13mm hex head screws. The engine needs to be
cool or cold during this exercise to minimize risk of injury. First, raise the car
and remove the coolant reservoir cap.
Remove both splash guards under the engine. The front has four 10mm plastic
nuts, the rear has five 10mm steel hex head screws.
Remove the two heat shields attached to the main suspension cross-member. There
is one on each side of the sump. Both are attached with four 10mm screws, with one
screw each being accessed through a hole in the cross-member. You may have to remove
plastic caps to access these. The right-side shield requires deft maneuvering to get
it out. Once you figure it out the only thing I can guarantee is that it's twice as
hard to get it back in.
A caution at this point: There is a live
electrical terminal nearby on the starter which is almost impossible not to touch with the
right steel shield while removing or replacing it. Either disconnect the battery or
tape over the terminal with three layers of duct tape. This terminal is not
fused and can be extremely dangerous if shorted! Do not take a chance.
The drain plugs on the block may have colored paint on them. One can be
loosened with a 13mm socket on about a 12-inch extension, the other will need a 13mm
crow's foot, or in a pinch a box wrench will do. The first will yield about 2
gallons of coolant, the second just about half a gallon. I used a section of hard
vacuum cleaner pipe to aim the coolant into a bucket and minimize spillage.
Remove the plastic drain plug at the left end of the radiator and be prepared to
collect about half a gallon of coolant. You may want to switch on the ignition and max the
heater controls during this step to improve the chance of draining the heater cores.
Take care not to splash coolant in your eyes, and wash them immediately if you do.
Stick the garden hose in the filler opening and squirt a few gallons through to flush
out the system.
Clean and replace the block drain screws - apply a non-hardening sealant on the upper
half of the threads first, such as Permatex High Tack Adhesive Sealant. Note there
are aluminum gasket washers present which I didn't bother to replace. Tighten
firmly, a suitable torque value is 20 ft-lbs.
Replace the radiator drain plug and tighten slightly (it doesn't need to be
tight to not leak.)
Replace the heat shields and splash guards, and optionally lower the car to the
ground.
BMW cars require antifreeze free of phosphates to prevent damage to the aluminum
radiator. I would suggest using the factory stuff exclusively, especially if your
car is still under the full warranty. The stuff I bought from BMW seems to made in
the US anyway, probably "exclusively" to improve their profit margin.
Water is mixed 50/50 with antifreeze to make engine coolant (in very cold climates, a
higher ratio of antifreeze, say 60/40, may be used.) It's not recommended to use
distilled water (per Click and Clack,) but filtered water can't hurt. Add 6.25
liters (6 quarts) of antifreeze to the reservoir first, then fill with water until the
system is completely full. There is no bleed screw on this system, and none is
required.
 The "cold" level is
marked on the tank.
The system capacity for the M60 is 12.5 liters (3.3 gallons.) Expect this amount
to be reduced by coolant trapped in the heating system, about 500 cc's (1 pint.)
Carry some water the first time you drive the car in case additional coolant is
needed. Note the mileage and date for your records.
FYI, you can read the thermostat temperature and part number by removing the upper
radiator hose, engine end. Much easier to do while the coolant is out.
Further Tips
Be cautious when removing or refitting radiator hoses attached to the plastic tanks.
Do not work them too hard or apply a lot of force when removing. Tighten the
hose clamps gently when re-installing, you can always tighten them later if they leak but
you will be really mad if you crack the plastic!
Put a soapy lubricant under the hose clamp to allow the rubber to slip while
tightening. Hand cleaner or dish soap will do.
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