One of the most common tasks to perform is replacing your
engine oil. Frequent oil changes are supposedly the most important thing you
can do to maintain and prolong the life of your engine. With the better oils
that are available today, the requirement for frequent changes is diminishing.
Even though BMW now recommends oil change intervals that are much farther apart
than in the past, I usually recommend that you keep the changes under the
5,000-mile limit. If you don’t drive your car too often, you should change the
oil at least once a year to keep things fresh.
The first thing you need to do is
to make sure that you have everything that is required for the job. Nothing is
more frustrating than emptying your oil, only to find out that you don’t have a
replacement filter or enough oil. You will need an oil filter, a wrench, a roll
of paper towels, a very large oil pan or bucket, and between 4-7 quarts of oil.
The E30 cars require between 3.5 - 4.2 quarts, and the E36 cars require 5
quarts for the four-cylinder cars, and 6.0-6.5 for the six cylinder cars.
You'll also need a 17mm or 19mm wrench to remove the drain plug from the bottom
of the engine sump. Start by driving the car around, and letting it heat
up to operating temperature. You want to empty your oil when it’s hot, because
the heat makes the oil flow a lot easier, and more particles of metal and dirt
will come out when the oil is emptied.
Once you get the car parked, place
the oil pan bucket underneath the oil tank of the car. At the bottom of the
engine sump there is a plug that is used for draining oil . Remove this plug carefully, and make sure you have a very large oil
pan—about 7-quart capacity—under it, with a drip pan under the oil pan in case
you underestimate. The oil will be very hot, and will empty out extremely
quickly, so be careful not to burn yourself. There will be no time to grab any
more buckets or oil pans, so make sure that the one you choose is big enough.
This is a good time to remove the
oil filter. You want to make sure that you remove the filter with the oil pan
still under the oil tank because the oil filter is full of oil, and this oil
will have a tendency to drip down out of the filter into the tank and out the
drain hole. On E30 cars, the filter is a complete unit with a outer metal
housing. This filter should only be screwed on finger tight, but you may
need a filter wrench to remove it. If the filter is really on tight, you may
need to resort to more drastic measures. One sure-fire way to get the oil
filter off is to poke a long screwdriver through it and use the handle of the
screwdriver for leverage. It doesn’t matter that you are destroying the filter,
because you are going to install a new one. Be aware, though, that this method
will leak oil out of the filter into your engine compartment, so have some
paper towels handy.
On the E36 cars, the filter is a
cartridge-type filter which is contained within a metal oil filter housing. There is a cap that is located on top of the housing (it may
require a small socket, or a large one depending upon your year). Remove
the top , and underneath you will see the cartridge filter. Simply remove
it from the oil filter housing. Have plenty of paper towels on hand, as oil will spill from the
filter if you're not careful.
While all of your oil is draining, take
the plug from the engine, and carefully clean it with a paper towel. The plug
at the bottom of the engine is magnetic, and attracts all the little bits and
pieces of metal that get trapped in the engine oil. When both plugs are
clean, replace them in the car with new metal gaskets around the plugs. If you
don’t use the gasket, they will leak oil. Torque the two plugs to 25 Nm (18
ft-lbs) for the 17mm or 60 Nm (44 ft-lbs) for the 19mm drain plug.
Now head back into the engine
compartment, and install the new oil filter (E36 Filter -. For the E30 cars, install the oil filter with the seal wet—wipe a
small bit of oil on a paper towel, and use it to make sure there is oil on the
seal all the way around the filter. Screw on the filter and make it snug tight.
No need to use the iron grip of death when tightening the oil filter—these
don’t have a tendency to leak.
For the E36 cars, you should clean
out the inside of the oil filter housing before installing the new oil filter
cartridge. In your oil filter kit, you should also have two o-rings and a
replacement copper gasket for the long bolt that attaches the top of the housing
(early E36 cars). Replace the o-ring at the bottom of the long bolt , and also replace the large o-ring underneath the canister top . Insert the new filter into the housing , and reinstall the long bolt and the canister top. Tighten the
top of the canister to 25 Nm (18 ft-lb).
Now it’s time to fill up your BMW
with motor oil. A lot of people aren’t really sure what motor oil to use in
their car. Traditionally, the characteristics of motor oil were linked closely
to its weight. Heavier-weight oils protect well against heat; lighter-weight
oils flow better in cold. In general, if you live in a cold climate, you should
use a 10W-40 or similar oil. This oil is a 10-weight oil that behaves and
protects against heat like a 40-weight oil. In warmer climates, you should use
a 20W-50 oil. This oil doesn’t flow as well at the colder climates, but gives
an extra “edge” on the hotter end.
The question of whether to use
synthetic or traditional “dinosaur” oil often comes up among car buffs.
Consumer Reports (July 1996) ran an extensive test on the two types of oil,
altering amongst many different brands. The testers installed freshly
rebuilt engines in 75 taxicabs, and then ran them through the harshest
conditions on the streets of New York City. Placing different brands,
weights, and formulations in the cars, they racked up 60,000 miles on the
engines, tore them down, measured, and inspected the engine components for wear.
The oil was changed at 3,000 miles in half of them, and the rest were changed
at 6,000 miles. results: regardless of brand, synthetic or dino, weight, and
oil change interval, there were no discernable differences in engine component
wear in any of the engines. Their conclusion? Motor oils and the
additives blended into them have improved so much over the years that frequent
oil changes and expensive synthetics are no longer necessary.
Still, some people swear by
synthetic oil. In practice, I don't recommend using synthetic oil if you have
an older car with old seals in the engine. There have been many documented
cases in which the addition of synthetic oil has caused an otherwise dry car to
start leaking. If you own an older BMW that doesn’t have fresh seals in the
engine, I would stick to the non-synthetics.
Fill your oil tank from the oil
filler hole in the top of the valve cover , located in the engine compartment. Add about 4 quarts to
the engine, and check the dipstick. Continue to add about a half a quart
at a time and keep checking the dipstick. Fill it up until it reaches the
top mark of the dipstick - the engine oil level will automatically lower when
the oil filter fills up with oil. Make sure that you put the oil filler
cap back on the top of the valve cover, otherwise, you will end up with a messy
engine compartment when you drive away.
Now, start up the engine with the hood
open. The oil pressure light should stay on for about a second or two and
then go out. Hop out of the car and look at the engine compartment, then
take a quick look underneath the car. Verify that there's no volumes of
oil seeping out of the engine. Now, take the car out for a drive and
bring it up to operating temperature. Shut the car off and then recheck
the oil level (careful, the car will be hot). At this point, I like to
top the oil off at the top point on the dipstick. Make sure that you
dispose of your old oil at a respectable recycling station.
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