DIY 30K maintenance on a 2004 Subaru Forester

Well my Subaru Forester has hit 120,000 miles and a check engine light on, meaning it's once again time for a round of 30k maintenance.  I'll admit I've never been a car guy (bikes and computers have been more my thing), but after getting screwed at the local Local Subaru Dealer back in 2009, I've vowed to be more hands-on as far as what's up with my car.  Not to mention, it's spring, the ski season has sucked, and I'm bored.

If you're looking to do the same, here's the tools needed:

• 12" breaker bar (preferably 1/2" end, but 3/8" + adapter is OK) $8
• Ratchet wrench set including 10mm, 12mm, 15mm, and 17mm sockets $22
• T-70 bit socket $5
• Phillips head screwdriver $5
• Needle Nose pliers $5
• Oil funnel with extension hose $5
• Spark Plug Gapper $3

Total tools cost = $53


And here's the parts I used:

• TYC 800075P Cabin Air Filter $15
• Fram CA9113 Engine Air Filter $7
• Beck Arnley 043-0979 Fuel Filter $20
• Fram TG3593A Oil Filter $8
• Dayco 5050350 Alternator and Power Steering Belt $14
• Dayco 5040353 A/C and Idler Belt $11
• NGK BKR5EGP Platinum Spark Plugs $12
• NGK FX 58 Spark Plug Wires $43

Total parts cost = $110

Lastly, list of oils and fluids used:

• 5 quarts Castrol GTX 5W-30 Syn Blend Engine Oil $22
• 2 quarts Castrol 75W-90 Limited Slip Synthetic Gear Oil $18
• 1 gallon Valvoline Dexron III /  Mercon automatic transmission fluid $20
• 2 12 oz bottles Wearever Gold Premium Synthetic DOT 3 Brake Fluid 
• 1 gallon Subaru Long Life "Green" radiator coolant $30
• 1 gallon distilled water $1
• 1 4oz bottle Subaru coolant conditioner $4

Total oil / fluids cost = $110

Step 1: Replace the Cabin Air Filter

Cabin filters : Old (left), new (right)

Just remove the glove compartment (owner's manual on page 4-18) and take a look.  This is the filter they love showing at the mechanic because it gets dirty really fast and you should really replace it every 18 months.  Mine was saturated with dust and and even had leaves in it, but thankfully no mold.
  

Purolator C25875 was an exact match for the installed one, but it was sure disappointing to pay $40 for what's basically paper and plastic.  Next time may try to make one and save some dough.

Step 2: Replace the Engine Air Filter

The Engine Air Filter is the big black box in the back middle held by a couple 10mm bolts and three metal clips.  Here's a video showing it well.  Getting it out takes some jiggling, but it'll eventually pop out.  Mine was a brownish yellow and no arguing it was due to be replaced. 

The genuine Subaru filter is just paper and plastic, so nothing fancy.  Two options are the Purolator Classic and Fram Extra Guard.  Between the two, I would definitely recommend the Fram.  It's much better built and the prices are about the same.

Step 3: Replace Fuel Filter

My new fuel filter

You’ll need goggles, pliers, and a screwdriver for this one.  This video is for an Outback, but the Forester is no different.  Watch for splashing gas when pulling off the hoses.  

Compatible parts are Purolator F54668, DriveWorks DW-54668, or Beck Arnley 043-0979. They all look the same and cost about a little over $20.

Step 4: Engine Oil Change

New Oil and Filter read to go

The manual recommend SAE 5W-30 oil and about 4.2 quarts of it to do a complete change.  The manual also said either regular or synthetic oil would work, Subaru mechanics always recommend synthetic blend.  The local O'Reilly had a special on Castrol GTX so that was an easy decision.   I just went with the regular synthetic blend, not the high mileage version.

For the filter, everyone recommended spending couple bucks on a good one such as the Purolator PureOne or Fram Tough Guard.  Bosch and Wix are also popular. 

As for the procedure itself, I think this video is probably the most complete one out there.  The drain bolt takes a 15mm socket to remove, and it was in so tight I had to buy a breaker bar to get it off.  The filter was also a pain to remove, and I had to give it a pull with groove point pliers on to get started.  

Step 5: Transmission Fluid Change

Draining the last bit of old fluid

The procedere is identical to a regular oil change, but easier.  Look under the center front of the car and you'll see a black box with a large drain bolt on the driver's side.  I was able to loosen the bolt easily with a ratchet and 17mm socket purchased down at the local Ace hardware for $6.  Be careful when the bolt finally comes out, because there's about a gallon of fluid inside and it will come out under high pressure and may be hot if you've just driven.

I used Valvoline DexronIII / MEX as the replacement fluid.  A gallon jar was $20 at the O'Reilly.  Premium brands like Redline and Royal Purple were also available for about twice the cost.  The fill is the tiny yellow handle on the driver's side.

The 17mm transmission drain bolt

As with an oil change, there's the optional step of replacing the drain bolt. Mine looked fine, so I did not worry about this. There's also the optional step of replacing the transmission filter. I read on the Subaru forums that this only needs to be done during a fluid flush, so I didn't worry about that either.

Step 6: Front Differential Oil Change

The front diff drain plug, with T-70 socket

The manual recommends 75W-90 synthetic and prices will go between $8 and $12 per quart.  Mobil, Valvoline, and Lucas are popular brand choices.   Some swear by Red lIne ($15) or Royal Purple ($20) but the guys at O'Reilly said unless you're racing, there's not a huge incentive to pay more than $10 a bottle.

The front differential dipstick

The drain for the front different is directly in front of the transmission fluid box, and and has an unusual looking "star" socket.  This is called a T-70, and I lucked out and found it for $4 at AutoZone.  If not, large sellers like Amazon have them for $6 or $7.

The filler looks a lot like the transmission, but is on the passenger's side and is labelled "diff".  It's common to get this confused with the transmission (driver's side), so make sure you've got the right one before putting the oil in.

Step 7: Rear Differential Oil Change

After doing the front, this will be a piece of cake. Simply locate the differential, remove the bottom plug, drain, replace, remove top plug, and fill.  It takes 800ml of the same 75-90, so assuming you bought two quarts for your front differential, there should be just enough to fill it.  Here's a YouTube video for a 2009 Impreza but the steps are identical.  He used a "turkey baster" type tool to get the new oil in; I used a 1/2" wide hose.  

Step 8: Steering Fluid Change

The steering fluid type is exactly the same as the transmission - Dexron III / MEX.  Locate the hose under the car, drain the old fluid, and refill.  You'll need about 2/3rds a quart when doing a full flush.  Subaru Forester forums has a nice write-up posted.   

Step 9: Replace Accessory Belts

Old accessory belts with noticeable cracks

The accessory belts are the two smaller rubber belts in front of the engine.  On the passenger's side is the Alternator / Power steering belt, and on the driver's side is the A/C belt.  Worn out belts will cause "squealing" when starting up or jerky steering, and should be replaced if any cracks are showing on the inside.  A mix of 10mm and 12mm sockets will allow you to remove the covers and get enough slack on the belts so they can be changed out.  Once again, SubaruForester.og has an excellent write-up complete with pictures.  
  

Step 10: Radiator Coolant Change

Note - Subaru recommends a timing belt replacement at 105,000 miles. If that has not been done yet, coordinate the timing belt change with the coolant change, since replacing the timing belt and/or water pump requires the coolant be drained. 

First, drain out the existing coolant. The plug is located in the lower corner of the radiator on the passenger's side. It will take 10 minutes for all the coolant to drain and will be messy, so be sure to have a pan underneath. To refill, mix a 50/50 formula of Subaru coolant and distilled water. The system takes about 1.7 gallons, so there will be some of coolant and water left over. I'd recommend storing the coolant in case of leaks or spillage. Once the coolant is near full, dump in the 4 oz bottle of coolant conditioner. Remember that hot coolant will expand, so leave some room towards the top still. The final step is to "burp" the system by starting the car up with the hood up and radiator cap off, then revving the engine a few times. 

Step 11: Replace Spark Plugs & Wires

While replacing spark plugs usually isn't much of a challenge, the horizontally opposed engines of the Forester present a special challenge.  Switching out the plugs will take about 2 hours, and require removal of the air intake, wiper reservoir, and battery. Spark plugs are cheap ($12 for 4 NGK BKR5EGP G-Powers)