How to Replace the Timing Belt, Idlers, Water Pump and Thermostat on a 2.5L Subaru Legacy 2009 to 2013

     This periodic maintenance job is easier than most on the Legacy and well within the capabilities of
most home mechanics. A crank pulley holding tool is the only special tool we needed for this job.

                                                     Tools and Materials

• Tools:  Crankshaft holding tool  , 1/2" breaker bar (the longest you have), 10,14, 15,and 22mm sockets, pliers for hose removal, 
• Parts: Timing belt, Water pump, thermostat, three idlers and tensioner, We used Subaru parts. 
• Materials: Coolant and conditioner. We used Subaru. 
• Time: 5 hours     

Initial Disassembly

1) Disconnect the battery
2) Drain the coolant. Remove large undercover panel (an assortment of panel fasteners) It is fastest and easiest to unclamp and pull back the lower radiator hose.
3) Remove the plastic belt guard (2 panel fasteners) and the air intake (2 panel fasteners) at the front of the car.
4) Remove the serpentine belt by turning the 15mm tensioner bolt clockwise while pulling off the belt

4) Remove the upper radiator hose with a vice grip or hose clamp pliers.
5) Remove the passenger side cooling fans. First remove two 10mm bolts. Then unplug the electrical connector and pull the fan up and out. .
6) Remove the driver's side cooling fan. First remove the coolant overflow bottle. Also on the driver's side, free a hose that is routed through the lower fan frame. Unbolt the two 10mm bolts and unplug the wiring. The fan will now pull up and out of the car.
7) Remove wishbone bracket. Three 15mm bolts, two upper and one lower toward the passenger side.

Remove these three 15mm bolts holding the bracket

8) Unplug two electrical connectors from the passenger side.
9) Remove the crankshaft pulley bolt. Use a holding tool, bracing it on the passenger side wheel well. It is helpful to move the air box a bit to get the tool positioned at a right angle to the pulley. Use a long breaker bar to turn out the 22mm bolt.

10) Remove the harmonic balancer. A few back and forth taps with a hammer should suffice to get it heading out.
11) Remove all timing belt covers (14 10mm bolts). There is one different length bolt on the lower middle of the passenger side cover.

Removal of Timing Belt and Water Pump

1) Line up engine timing marks for the cam sprockets and crank sprocket. Rotate the engine clockwise until all three are aligned. Then keep them there. 

Crank sprocket timing marks and pass cam (below)

2) Remove the lower smooth idler with a 14mm socket and ratchet.

3) Remove the upper smooth idler with a 14mm socket and ratchet.

4) Remove the timing belt.

5) Remove the toothed idler near the water pump with a 14mm socket and ratchet.

6) Remove the tensioner with a 14mm socket and ratchet.

7) Remove the six water pump mounting bolts with a 10mm socket and ratchet. A three inch extension bar will be needed here. These bolts are not heavily torqued.

Remove these three and three on the under side

8) Unclamp and remove the hose below the pump and remove the pump

Remove and Replace the Thermostat 

1) Remove the two 10mm bolts holding the thermostat housing from the old pump with socket and ratchet.
2) Install new thermostat in the new pump assembly
3) Position the thermostat housing properly and bolt to the pump using the two 10mm bolts.
4) Torque to 8.9 ftlbs.

Install Water Pump

1) Place new gasket and six bolts on the pump and carefully position against mounting flange on engine. 

2) Turn in crosswise and in stages. Torque the bolts to 9ftlbs. 

3) Install the two hoses on the pump. 

Install Idler Pulleys, Tensioner and Timing Belt 

1) Install the upper idler just to the left of the crank pulley and torque the 14mm bolt to 28.8ftlbs.

2) Install tensioner and torque the 14mm bolt to 28.8ftlbs.

3) Install timing belt. Align the marks on new belt with the timing marks on the cam and crank sprockets. Follow the routing as shown below. It will be loosely installed for now.

4) Clip the belt to the cams with a couple of small clamps to prevent any movement.

5) Install the toothed idler and torque the 14mm bolt to 28.8ftlbs.

6) Install the remaining passenger side smooth idler. Be careful to keep it flush as it is positioned. The tension of the belt will make this challenging. Turn the bolt in slowly and carefully to avoid cross threading. 

There will be downward tension from the belt providing a challenge

7) Activate the tensioner by pulling out the pin. 

8) Rotate the engine two full clockwise revolutions by hand, using the 22mm crank pulley bolt. Make sure there is no undue resistance and the timing marks remain aligned. The belt marks will not align again, 

9) Remove the crank pulley bolt by holding one of the cam pulley bolts as you turn it out counterclockwise.

                                         

Install Timing Covers, Balancer, Crank Pulley bolt and finish

1) Install the timing covers with the 14 10 mm bolts. Torque to 3 ftlbs if you have a wrench that measures such light torque. If not torque lightly. 

2) Install the harmonic balancer.

3) Install the crank pulley bolt. Insert the holding tool. Torque to 34.7 ftlbs plus 60 degrees. If your torque wrench does not measure degrees make a mark on the holding tool at 60 degrees and stop there.

Make a mark on the tool at 60 degrees from breaker bar start 

4) Install the support wishbone and torque to 26.6 ftlbs.

5) Install the serpentine belt by turning the 14mm tensioner bolt clockwise while slipping the belt back on. 

6) Install the fans with the 10mm bolts. Plug in the electrical connectors and route the hose on the Driver's side fan. 

7) Install the coolant overflow bottle. 

8) Plug in the two electrical connectors on the passenger side.

9) Reconnect the battery.

10) Fill with coolant and conditioner as recommended by Subaru. 

11) Run up to operating temperature (lower hose hot). Let cool and check level and add if needed.

12) Install the belt guard and air intake removed earlier.