Freightliner XC Chassis Radiator Surge Tank Replacement
Ratchet with 14mm socket and short extension
14mm open/closed end wrench
Long flat blade screwdriver
Small phillips screwdriver
Two one-gallon water jugs
About one hour.
Gain access to the top of the tank from inside the motorhome. For a 2004 Discovery: use a quarter to remove
the four large screws of the access panel located inside the rear wardrobe closet. Pull up the carpet along the
passenger side edge and dispose of carpet staples left in the floor. Lift the passenger's side of the access
panel and support open to 45 degrees or better.
Slide the two small hose clamps away from the vents on top of the tank with pliers. Grasp the hoses and apply a
gentle twisting force on the hose itself with the pliers to break the grip. Slide the hoses off, noting which hose
Remove the two driver's side 14mm bolts and nuts. The rear bolt should remain captive by the structure below,
and can be reached from the side with the 14mm wrench. Remove the forward passenger's side bolt and nut.
From the outside, remove the phillips screws holding the passenger side edge of the vertical black rubber
shield. Pull the shield over the transmission filler cap and fold away as much as possible. Remove the clamp
holding the transmission filler tube in place. Push the tube down so the 14mm wrench can get a grip on the
inside nut and remove the bolt and nut.
From the inside again, remove the small overflow hose on top. Disconnect the sensor connector by lifting up
gently on the retaining clip first and then pulling the connector straight back. Slip the clamp off the large lower
hose and wriggle almost free. Place towels under the hose and disconnect the hose. As soon as the hose
comes free, place your thumb over the surge tank opening to minimize fluid loss. Lift the tank out and drain
contents into the two one-gallon jugs. You should only have lost about a cup of fluid.
Remove the old tank sensor with a crescent wrench, noting that the black switch housing is off-center, closer to
the top. Insert the sensor into the new tank and tighten until the sensor is snug and the housing is in the same
position as with the old tank to duplicate the previous tightening torque. No tape or dope should be required
because of the existing small nylon washer.
Put the new tank into position and replace the four retaining bolts, four hoses, and switch connector. Note: the
flat screwdriver can help in lifting the rear driver's side bolt up until the nut and washer are connected. Refill the
tank with the collected fluid, and replace the spilled fluid with an equivalent amount of distilled water. Swap the
radiator cap from the old tank. Reposition the access cover. Go back outside and reposition the transmission
filler tube and rubber shield.