I started by pulling the XJ in the garage and disconnecting the
battery. I then removed the grill to give easy access to the petcock so
I could drain the radiator (also, it would allow for an easy
installation of the trans cooler....more on that later).
After giving it a little while to cool down I removed the radiator cap,
attached a hose to the drain, positioned a catch pan and and opened the
petcock to let the antifreeze drain out.
the cylinder block drain plugs, radiator cap or open the petcock while
the engine is hot or the cooling system is under pressure. You're
likely to burn yourself. Also, antifreeze is poisonous. Children and
animals are attracted to it due to the color and odor. If you suspect a
child has consumed any antifreeze, immediately call 911 or your local
poison control center. Make sure to dispose
the antifreeze was draining,
I took the opportunity to remove the
electric fan and mechanical fan shroud. Each is held in place by two
bolts into the radiator crossmember on top (three of which also hold
the overflow hose in place) and by two tabs into a bracket on the
radiator at the bottom. For the electric fan, I disconnected the plug,
removed the two top bolts and pulled straight up on the unit to remove
it. For the shroud, I removed the bolts, pulled it straight up and
placed it over the fan for the time being. Then, after marking where
the hood latch lines up, I removed the bolts that hold the crossmember
in and removed it. Click on the photo at left for larger image.
Next, I removed the upper, lower and heater hoses. Then it was onto
transmission lines. The upper connection was threaded into the
radiator, so after applying generous amounts of PB Plaster, a line
wrench took it right off. The lower Transmission line was a little
It was actually molded into the radiator. There was a "quick connect"
fitting to connect the line to the radiator. Because of space
limitations, there was nothing "quick" about it...but after some
cursing it finally disconnected.
it was time to remove the radiator. Since the XJ has A/C, there is a
condenser that sits in front of the radiator and they are held together
on top with a bolted bracket and held together on the bottom with two
dowels on the radiator that go through a bracket on the condenser then
into dowel holes in the frame. I simply removed the bolts on top and
pulled straight up on the radiator to remove it. Then I removed the fan
shroud (previously placed over the fan). Now that there was some room
to work, it was onto the front side of the engine... Click on the photo
at left for larger image.
I removed the two bolts holding the thermostat housing on and removed
the thermostat. Then, I loosened (but did not remove) the 4 bolts
holding on the mechanical fan and the 4 bolts holding the idler pulley
on the water pump (Since the belt is holding tension on these pulleys,
it's much easier to loosen them prior to removing the belt). Then,
after loosening the idler pulley bolt (under the power steering pump),
I loosened the belt tensioning bolt until the belt could be removed and
followed this by removing the mechanical fan and water pump pulley. Now
that all that stuff it off, it was time to remove the power steering
pump and bracket. There are three bolts that hold the pump to the
bracket and three bolts that hold the bracket to the engine...two to
the water pump and one to the engine block. Once these were removed, it
was time to remove the water pump. Four bolts and small tap with a
hammer later the pump was off. Click on the photo at left for larger
Prep and pre-assembly
Now that everything was apart, it was time to clean it all up for the
new parts. After stuffing rags in the water pump and thermostat
openings, I used engine brite to clean off all the dirt and grime. Then
I used a dremel tool to clean up the mating surfaces.
Next it was time for some preassembly: First, I had to remove the
heater hose pipe from the old water pump and install it on the new one.
So after I removed it, I put it to the bench grinders wire brush to
clean it up and then gave it a few good coats of hi temp black paint.
While I was waiting for the paint to dry, I cleaned up all the bolts I
intended to reuse on the bench grinder. I then installed the freshly
painted pipe onto the new water pump using thread sealant to ensure a
leak free fit.
Next, I removed the old viscous fan clutch from the fan by removing the
four bolts that hold them together and installed the new clutch on the
fan. Easy. I then moved onto the transmission line fittings for the
It comes with plugs in the trans cooler and all the hardware needed in
a bag. This took a little thought as to how I was going to run the aux
trans cooler lines, but I decided to just set it up to mimic what was
on the old radiator, of course, using thread sealant when installing
Finally, I installed the new coolant temperature sensor into the new
thermostat housing. The threads on the sensor came with sealer already
on them, so there was no need to add any more.
Now, it was time to get all this stuff installed.....
Transmission Cooler Install
was a piece of cake...namely cause I've installed one of these before
(actually I've installed 4 of these in various vehicles I've owned). It
installs in tandem with the existing cooler (built into the radiator)
by going inline on the supply tube from the transmission. So first, I
to determine which line was the feed from the tranny. On the AW4 (like
most Chyco transmissions), the rearward line on the tranny is the
feed...which translated to the lower line on the radiator. After
figuring out all the hose routing, it was time to mount the cooler. I
installed it in front of the condenser, pretty much right in the
middle...which worked out well since it was dictated by hose routing.
Click on the photo at left for larger image.
The cooler installs with a sort of zip strip that goes through the fins
of the condenser. Pads keeps the cooler from damaging the fins. Click
on the photos below for larger images.
After running the hoses into the
engine compartment, I attached them to the cooler with clamps and
mounted the cooler to the condenser. Then I cut off the quick connect
from the old radiator and flared the non quick connect end. I then
placed one hose from the cooler over the flared end, secured it with a
clamp and snapped the other end back into the quick connect. That's
it...the other end of the hose will get connected to the radiator.
Water pump, Thermostat and Serpentine Belt
These are pretty easy too. On the water pump, I applied some Black RTV
to pump side of the gasket, put the gasket on the pump and then put RTV
on the other side of the gasket. Then, after dressing the bolts with
thread sealer and placing them through the pump to hold the gasket in
place, I put the water pump on, threaded the bolts in and torqued them
to spec. Onto the thermostat....
During the research phase of this project, I came across the TurboCity
hi flow thermostat housing. Normally, I look at stuff like this as
snake oil...but since I felt that the stock housing was restrictive
anyway, I decided to snag one as well as a matching hi flow thermostat.
Total cost was less than $40 shipped and after comparing it to the
stock unit, I think it makes a difference....they say pictures are
worth a thousand words...you can clearly see how the ported housing is
less restrictive and how the new 'stat will allow more flow as
well. Click the photos below for larger images.
the thermostat has an air
vent hole that needs to be at the top. After it was all snug in it's
recess and in the correct position, the housing was installed just like
the pump...RTV on the gasket, thread sealer on the bolts, torque to
spec. Click the photo to the left for a larger image.
Then (just to get them out of the way) I installed heater hoses...one
goes to the water pump, the other to the thermostat housing. Next it
was onto the serpentine belt...
I reinstalled the PS
bracket, followed by the PS pump (using anti seize compound on all the
bolts) and torqued them to spec.. Next, I installed the pulley on the
water pump as well as the mechanical fan getting the bolts snug. Then,
after routing the belt around it's proper path along the pulleys, I
cranked down on the tensioning bolt and using the gauge, set the belt
tension to spec. Then, I tightened all the remaining bolts to spec and
laid the shroud over the fan. Onto the radiator install.... Click the
photo to the left for larger image.
Radiator and final re-assembly
Pretty much the reverse of taking it out...the trick was getting
everything to line up correctly. After lining up the dowels on the
radiator, with the brackets on the condenser and the holes in the
frame...the radiator dropped in. Then I connected tranny feed line
(from the new cooler) using a hose clamp and followed that by
installing the lower radiator hose (using Indian Head, of course).
Then, after applying thread sealant to the fitting, I attached the
tranny return line to the radiator. Next I attached the upper hose and
bolted the crossmember back in. This was followed by getting the fan
shroud and aux. electric fan tabs to line up and drop in. After running
the overflow line back to the radiator the final bolts went into place
and the aux fan and temp sensor connectors were hooked back up. At
which point I filled the radiator with half Prestone Extended Life
antifreeze/half water and installed the new radiator cap.
Then I reconnected the battery, started it up, checked for leaks and
topped off the tranny fluid.
I could not be more happy with this upgrade. As I stated at the start,
the Jeep has always run at around 210 degrees...even in cooler weather.
Since doing this upgrade (and driving a few hundred miles now), it has
yet to hit that mark...as a matter of fact it runs between 190 and 200
degrees now. That's a 10-20 degree drop...a huge improvement. I would
recommend similar upgrades to anyone that owns a Jeep. To the folks
with automatics, I highly recommend installing a tranny cooler. Every
20 degrees you lower the transmission fluid temp, you will double the
life of the tranny....you can't beat that for $50 and getting your
hands a little dirty.
Please note that this
writeup reflects my experiences only and anyone using it for reference
or as a guide, etc. does so at their own risk. You may link to this
writeup, but you must obtain my permission to re-post it elsewhere.***