Subaru Forester 2014 2.5i PZEV ( California ) , with CVT
[ this is just for reference ONLY. showing what I have done to 2014 Forester. NOT intended for instruction on how to repair it or maintaining it. I believe it is missing many details and steps to be used as Instruction.]
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Service Manual and Schedule maintenance says , I should replace spark plug every 60 K miles. it took 4 hours to do this work.
so I replaced at 59K miles. 20% is rural highway driving 70 to 80 MPH, rest are urban highway and city driving.
space was tight, but with right total length and swivel , wobble type of short extensions attached together made it possible to unscrew plug and out new one in.
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New Spark Plug's TIP surface is Flat. Old 59K miles plug does not have flat surface TIP anymore.
with Naked Eye , TIP of new and old plug looks about same, but under microscope, I can tell there is wear on TIP ( rounded ).
NGK [ SILZKAR7B11 ] Laser Iridium Spark Plug is used for replacement, which is exactly same plug originally in engine, one came with new car.
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I moved Battery as service manual say to change Driver side.
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I found out that Socket total length of 12.5 cm ( 5 inch ) fit into tight "Spark Plug Well" space to remove spark plug.
specially important for spark plug close to firewall.
socket is 14 mm. 2 or 3 short extensions wobble kind.
such as 3/8 inch type 1.5 inch length out of set like
http://www.harborfreight.com/9-pc-wobble-socket-extension-set-67971.html or
http://www.ebay.com/itm/371502470280?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649 or
I realized Having 2 to 3 short wobble type extensions are necessary, without them, impossible for Socket and extension unit to fit into "Spark Plug Well". I tried longer 3 or 6 inch extension, but they do not fit into "Spark Plug Well", because they are not flexible, specially one close to firewall. There are not enough clearance between engine and frame. Only way I was able do is to insert together connecting 14 mm socket and 2 or 3 ( 1.5 to 1.75 inch long ) Wobble type Short extensions.
I had to first insert 14 mm Hex socket and 2 or 3 short wobble extensions into spark plug well, then after that I was able to attached Ratchet Wrench to it.
Then , I use flat screw driver to detach extension unit from ratchet, so I can remove Ratchet first, then remove socket and extensions from spark plug well.
I also tried Universal Joint 3/8 adopter, they looks like miniature universal joint of old rear wheel drive drive-shaft. But, it did not work for me.
Universal Joint example-- http://www.harborfreight.com/3-pc-universal-joint-socket-adapter-set-61955.html
extensions are 3/8 inch type. each short wobble extension is about 1.5 to 1.75 inch long.
connection between wobble type extension can have some curve like this. Without having curved Socket and extension Units, they can not be inserted into "Spark Plug Well", because of frame is too close to Engine Head ( Cam shaft cover ).
Length of short extension is a little bit longer than 1.5 inch TIP to bottom.
wobble extension have round head like in this picture, so connection between extension can have some curve.
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After unscrew Spark Plug completely, because I use normal Socket, Spark Plug is still in Spark Plug Well.
so, I used magnet hand to remove spark plug once loosened inside.
Silver color Aluminum line Tube in picture on Frame is for Air conditioning. I have to be careful not to damage it.
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Torque wrench fit to tighten spark plug. But, Without wobble type extension Large wrench like this can not be used.
I had to first insert 14 mm Hex socket and 2 or 3 short wobble extensions into "Spark Plug Well", then after that I was able to attached Torque Ratchet Wrench.
I use flat screw driver to detach extension unit from "Torque Ratchet Wrench", so I can remove "Torque Ratchet Wrench" first, then remove socket and extensions from "spark plug well".
I found there is No room to insert Socket and Short extensions while they are attach to Ratchet or Torque Ratchet Wrench.
reverse is also same, I can not insert or remove Socket with shorts extension while attach to ratchet driver.
Ratchet, Torque Wrench, Extension and Socket I use are all 3/8 inch type.
I believe , able to insert tool into tight Space is most important thing to replace Spark Plugs.
Because of Wobble Type short extension, Extension Shaft and Wrench does Not have to be exactly Right angle.
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passenger side, I removed air filter unit and air intake unit.
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After Air Filter unit and air intake are removed on Passenger Side.
Air filter unit with White trash collector attached.
air intake removed. I just had to remove 2 Plastic fastener to remove Air intake Duct.
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Anti Seize lubricant on thread and dielectric grease on plug contact at tip.
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after thought.
I think after loosen spark plug with solid short wobble shafts , I may could used Flexible 3/8 inch extension to untwist spark plug. Flexible Cable extension is NOT very likely strong enough to initial loosing of spark plug. But, Spark plug has long thread , so it take many twist by hand to remove it. Flexible Cable extension might made it faster to do this work.
for next change 60 K miles later, I will probably buy one of those.
example of Flexible 3/8 inch extension->