How to Install a Radiator in a 1998 Toyota Sienna

Toyota introduced the Sienna minivan in 1998 to replace the Previa. The 1998 Sienna is powered by a 3.0-liter transverse mounted 1MZ-FE V-6 engine, mated to a four-speed automatic transaxle with selectable overdrive. The Sienna is cooled by a radiator that uses an aluminum core with plastic tanks. The automatic transmission cooler is integrated into the radiator and two electric cooling fans provide air flow.

Instructions

Park the Sienna on a level surface and set the parking brake. Allow the engine to cool before proceeding. Remove the radiator cap. Place a drain pan under the passenger side corner of the radiator. Locate and open the radiator drain valve. You should be able to open the valve by hand. If it is too tight, carefully open it with a pair of pliers. Allow the coolant to drain into the pan. If the coolant is clean, you can reuse it.

Compress the hose clamp on the upper radiator hose with a pair of hose clamp pliers and slide the clamp back onto the hose. There's a chance that these clamps have been replaced with aftermarket clamps; if so, use a flat-head screwdriver to loosen the clamp. Remove the hose from the radiator. Repeat for the lower radiator hose.

Locate the transmission cooler lines underneath the radiator. Place a drain pan under one of the lines. The clamps on these lines may also have been replaced, so either compress or loosen the clamp with the hose clamp pliers or flat-head screwdriver and slide the clamp back onto the hose. Pull the hose from the fitting and catch the transmission fluid in the drain pan. Place a piece of plastic wrap over the end of the hose and secured with a rubber band to prevent fluid from leaking from the hose. Repeat for the other hose.

Move to the cooling fans and disconnect the electrical connector from each fan. Use a small flat-head screwdriver to depress the locking tab while pulling on the connector.

Unbolt the two hold-down brackets on the top the radiator with a ratchet and socket. Lift the radiator and fan assembly out of the engine compartment. Unbolt the cooling fans from the radiator with a ratchet and socket. Remove the fans.

Pull the two rubber mounts from the bottom of the radiator and install them on the new radiator.

Mount the fans onto the radiator install the bolts and use a torque wrench to torque the bolts to 44 inch-pounds. Lower the radiator and fan assembly into the engine compartment engaging the rubber mounts in the holes in the bottom of the radiator support. Mount the upper radiator brackets, install and torque the bolts to 108 inch-pounds.

Push the transmission cooler lines onto the fittings. Compress the hose clamps with the hose clamp pliers and slide them over the fittings or slide the clamps over the fittings and tighten with a flat-head screwdriver.

Connect the cooling fan electrical connectors. Attach the lower radiator hose and slide the clamp over the fitting with the hose clamp pliers or tighten the clamp with a flat-head screwdriver. Repeat for the upper radiator hose.

Slowly fill the radiator with coolant. If using new coolant, use a 50-50 mix of ethylene glycol based coolant. Coolant can be purchased premixed. Make sure the coolant reservoir is filled to the lower mark.

Start the engine and allow it to run until it reaches normal operating temperature and the thermostat opens. The coolant level will drop. Add coolant to the radiator until full. Allow the engine to cool and add more coolant if necessary. Squeeze the upper radiator hose a few times and add more coolant if necessary. Replace the cap.