[click to enlarge]
Proper maintenance of your coolant will go a long way towards extending the
life of your radiator. The cooling systems on most cars are often very
neglected, as most owners don't know much about them. See the
Pelican Technical Article on Cooling System Flush & FAQ for more
information. The most vulnerable components in the entire system are
the radiator and the heater core, as they tend to be damaged by corrosion
and electrolysis. Poor maintenance of the system can result in the
build-up of corrosion elements in both the radiator and heater core,
creating clogs and leaks that decrease cooling performance.
If the engine overheats, the additional heat from the coolant can also
damage sensitive plastic attachments and components.
When replacing your
radiator, you want to make sure that you replace it with one that meets or
exceeds the OEM cooling standards. BMW cooling systems are infamous
for overheating problems. Therefore, it may be a wise idea to install
an aftermarket performance radiator that performs a better job of cooling
than the standard OEM one. I also recommend replacing your water pump,
radiator hoses, thermostat, and any hose clamps too. All of these
components can be damaged by a cooling system that has overheated.
It's also a good time to swap out your old belts.
Okay, the first step
in replacing your radiator is to remove all of the coolant from the system.
Pelican Technical Article on Cooling System Flush & FAQ for more
information. Now, we need to
gain access to the radiator. Remove the front
plastic panel that covers the front inside part of the engine compartment
(Figure 1). Four screws hold this panel to the car.
Now, it's time to remove your cooling fan. You will need a 32mm
wrench, and a special fan removal tool (Figure
2). Unfortunately, I have not found an easy method of removal that
does not require the use of this tool. The tool holds the two pulley
nuts enabling you to remove the fan pulley nut (Figure
3). Holding the fan pulley steady with the tool, twist and remove the
fan nut (Figure
Figure 5). It is important to note that this nut has reverse
threads, and needs to be turned clockwise to loosen it (Figure
Now, you need to remove the
fan frame with the integrated reservoir. The cooling fan housing frame
is held in with small plastic rivets (Figure
7). Pop these out to loosen the frame from the radiator (Figure
8). You will have to disconnect the overflow hose prior to
removing this frame (Figure
9). Also attached to the frame is the reservoir overflow hose.
This hose winds around to the left side of the car, and needs to be
disconnected near the power steering pump (Figure
10). This hose is shown disconnected in
Figure 11. Now, disconnect the coolant level sensor (Figure
12). With all of these hoses and connectors disconnected, you
should be able to remove the fan frame / reservoir from the car (Figure
With the frame out of
the way, now disconnect all of the hoses that are linked to the radiator.
There are two large hoses, one on the top left side of the car, and one on
the lower right. Loosen the hose clamp on the top left hose (Figure
14), and then pull it away from the thermostat housing (Figure
Figure 16 shows both sides of this hose. Now, disconnect the lower
radiator hose on the right (Figure
17). Then, remove the electrical connector for the radiator
temperature sensor (Figure
With the hoses
disconnected, now disconnect the automatic transmission lines, if you have
an automatic transmission in your car (Figure
19). See the
Pelican Technical Article, Replacing Automatic Transmission Lines for
The radiator is held
onto the chassis of the car with odd, complicated plastic clips. These
are very difficult to remove, and you may end up breaking them when getting
the old radiator out (Figure
Figure 21). Using a screwdriver in the center of the clip, pry it
out from the chassis and the radiator. You may have to play with these
clips for a short while to remove them. With the clips removed, the
radiator should no longer be attached to the car (Figure
22), and can be easily lifted up and out of the engine compartment.
Figure 23 shows the radiator removed from the car. The small
radiator attached to the center of the main radiator is the automatic
transmission cooler. Make sure that you have a catch bucket (kitty
litter boxes work very well) to capture all of the excess coolant and
automatic transmission fluid that will spill out (Figure
Figure 25 shows what
the engine compartment looks like with the radiator removed. When you
install your new radiator, or reinstall your old one, make sure that it sits
firmly on the rubber mounts attached to the chassis (Figure
26). It is possible to install it slightly cocked if you don't pay
attention to these mounts.
Figure 27 and
Figure 28 show the radiator reinstalled in the car. If you damaged
your plastic clips removing the radiator, be sure to replace them with new
ones. Reattach all of the hoses and connections. Use new hoses
on the large upper and lower radiator hoses. If your clamps look worn,
then replace them while you're in there too. Only use clamps
specifically designed for large rubber hoses - some generic hose clamps can
cause chaffing on the rubber when tightened. Then button up the front
29). Replace all of the coolant and bleed the system according to
Pelican Technical Article on Cooling System Flush & FAQ.
Well, there you have it - it's
really not too difficult at all. If you would like to see
more technical articles like this one, please continue to support Pelican
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Peter Pesce adds:
Thanks for the great articles and tips, keep them coming.
One comment on your "BMW Radiator Replacement"
article: You do NOT need to remove the cooling fan or shroud/frame to
replace the radiator in an E36 coupe (1993 325is in my case). I just
replaced mine this weekend, and had no problem getting the old one out and
the new one in. It took me a couple hours, doing it outside in the driveway
in 40 deg weather.
It would be good to note this in your article, as
the plastic necks on E36 radiators are a common failure point (mine failed
there) so a lot of people are doing this particular job, by choice or
necessity! You might also note that you can swap out the main upper and
lower radiator hoses with the fan and frame in place as well.
Thanks, and keep up the good work.
New York. NY