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Old 08-30-2015, 11:53 AM   #1
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Member#: 401965
Join Date: Sep 2014
Default Importance of valve cover gasket replacement? 07 impreza


I was just wondering if anyone had thoughts on how important it is to actually replace the valve cover gaskets? I have some oil getting on my spark plug boots, and I have 200,000 km on the car. Hoping to have the car for another 5 years or so but not sure how badly this needs to be done since it's not actually causing misfires as far as I can tell.
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Old 08-30-2015, 12:41 PM   #2
Hoon Goon
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Member#: 335538
Join Date: Oct 2012
Chapter/Region: South East
Location: TN
2007 STi - Kornluvr


It's fine as long as you aren't concerned about a nasty, oily, stanky mess that no one will want to touch. The situation will not improve, but sure you can drive it that way. I wouldn't.
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Old 08-30-2015, 01:16 PM   #3
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Member#: 403883
Join Date: Oct 2014

Also, you won't notice if something else bust a (oil/coolant/whatever) leak.

It's not expensive to replace the seals, particularly if you intend to keep the car for several years. The only thorny bit is squeezing the wrench onto some of the valve cover bolts may be a pain depending on your model.
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Old 06-04-2019, 12:39 PM   #4
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Join Date: Jun 2019
Default Valve Cover Gaskets on a 98 RS

Maybe someone here can point me in the right direction. I have a 1998 Impreza RS. Going to be pulling the engine to do head gaskets. When I look up getting valve cover gaskets, I need to know the engine number in able to order the correct gaskets. The main spot on the block has no numbers or anything stamped into it. The only thing I can find toward the front is the EJ25 stamp. Is there anything in the VIN that could help? Thanks!
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Old 06-04-2019, 12:43 PM   #5
Jersey Man10
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Member#: 427632
Join Date: Aug 2015
Chapter/Region: TXIC
Location: Texas
2011 Impreza WRX
Satin White Pearl


Call Subaru and give them your vin and ask for the parts.
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Old 06-04-2019, 01:01 PM   #6
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Member#: 80465
Join Date: Jan 2005
Chapter/Region: RMIC
Location: Denver
2001 2.5RS
Black Diamond Pearl


Try RS25.com. I'm pretty sure the 98 had the EJ25D, which has DOHC. 99+ they went with the EJ251 - SOHC. Providing the VIN to a dealer usually assures that you'll get the correct parts.
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Old 06-04-2019, 08:35 PM   #7
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Member#: 3409
Join Date: Jan 2001
Chapter/Region: NWIC
Location: Oly
98 My FMIC
Is bigger than yours.


Originally Posted by yarrgh View Post
Try RS25.com. I'm pretty sure the 98 had the EJ25D, which has DOHC. 99+ they went with the EJ251 - SOHC. Providing the VIN to a dealer usually assures that you'll get the correct parts.
Easy way to verify that is to just pop the hood and look at it.
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Old 06-14-2019, 12:47 AM   #8
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Member#: 503148
Join Date: Jun 2019
2002 Impreza WRX


Would a leak in the valve cover result in pressure exchange between barametrux pressure and engine internal pressure? Donít those to pressures need to be separate from each other?
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Old 06-18-2019, 10:26 PM   #9
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Join Date: Jul 2017

Can be done by hand but one of the bolts on the passenger side of my Saabaru is stripped and the shoulder is seized in the valve cover. Iíd wait till thereís a large amount of oil in the tube before messing around with those bolts.
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Old 07-02-2019, 02:54 PM   #10
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not expensive, might as well replace it to keep everything clean
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Old 07-03-2019, 06:30 PM   #11
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Join Date: Oct 2003
Chapter/Region: Tri-State
Location: Rockland County, NY
2004 Stg 2 wagon AT
16 BRZ. Both silver


I did it myself. Only lasted about two years because I obviously did not do something right with the gasket. Paid a professional to do it for $400 bucks. No leaks for the last 3 years. It was a pain in the ass to do, I would pay for it again but it will be awhile.
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Old 07-29-2019, 01:24 PM   #12
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Member#: 373604
Join Date: Nov 2013
Chapter/Region: MWSOC
Location: Detroit Area
2003 WRX


Originally Posted by DropStone View Post
Would a leak in the valve cover result in pressure exchange between barametrux pressure and engine internal pressure? Donít those to pressures need to be separate from each other?
Answer: Sort of.....Basically the intake manifold vacuums and piston blowby air are driving the crankcase pressures. The engine has a PCV system to help it deal with these sources of air or vacuum so it doesn't over- or under-pressurize, as well as cycle dirty air out of the crankcase to help with oil life.
Most crankcases are happy at Ī7kpa and in general run and just below atmospheric pressure anyway(-1 or -2 kPa). Plus a PCV system will flow a lot more air than most gasket leaks. A valve cover gasket leak is usually too small to make a large difference in crankcase pressure when your engine is running.
Even if you have a large leak, the crankcase will just push a little unmetered air out or in through the leak and live around 0 kPa, which is fine for a little while. But you'd have a ton of oil on the outside of the engine from the leak, the engine would catch on fire, you'd hit a bus full of nuns because you wouldn't be able to steer your car through the flames coming out your hood and then when you wake up in heaven, you'd have a bunch of pissed off nun's to content with.
Moral: Fix your valve cover gasket leaks before you end up getting the snot beat out of you by 20 angry nuns.
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Old 08-22-2019, 10:19 AM   #13
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Member#: 505279
Join Date: Aug 2019
Chapter/Region: NESIC
2007 WRX


Definitely replace that in the near future. If its leaking, it'll only get worse. You will be able to drive it as long as you keep your oil levels up, but don't expect to get 5 more years out of it running like that.
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Old 12-30-2020, 04:02 AM   #14
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Member#: 157851
Join Date: Aug 2007
Default Notes on 07 WRX Wagon Valve Cover Gasket Replacement

Long time member, first time poster here. I've gotten so many helpful tips on maintenance from nasioc and other subie forums, I wanted to give back and post some notes on my recent DIY valve cover gasket replacement effort.

Since it's my first post, I can't start my own thread, so I'm adding to this existing, albeit very old thread (apologies).

Without further ado, here are my random notes from by R&R:
  1. My car: 2007 WRX Wagon 5MT, 114k miles
  2. Parts I used:
    • I used the Fel-Pro gasket set, VS 50620 R. I can't attest to their reliability, since I just did this job yesterday. I will try to post an update on how they hold up in the future.
    • My model year did NOT require the half-moon cam journal seals. Someone more knowledgeable may know if there was a transition during the '07 model year, or if all '07s have the updated heads.
    • NGK Iridium plugs ILFR6B
    • Oil Filler Tube O-Ring, Subaru 806922120
  3. Parts I wish I had on-hand before starting the job, but obtained afterwards:
    • Subaru 11815AB960 Driver's side front PCV hose
    • Subaru 99081AA060 Driver's side rear PCV hose
    • Subaru 11815AB143 Passenger side front PCV hose
    • Subaru 99071AB333 Passenger side read PCV hose
    • The hoses will be brittle and a pain in the ass to remove, especially the passenger side (turbo heat). I cracked 3 out of the four during either the removal or reassembly process. I wish I had gotten the hoses before starting the job. It was real pain to identify the rear hoses' part numbers (99071* and 99081*) when navigating the Subaru parts diagrams online. Even the dealer had some difficulty finding them. Hopefully this helps someone from going through the pain I did.
  4. Supplies I used:
    • Two or three cans of brake cleaner
    • One 3oz tube of Permatex Ultra Grey
    • Anti-seize for the spark plugs
    • Dielectric grease for the coil pack boots
    • Several pairs of rubber gloves
    • Shop towels and rags
  5. Tools I found indispensable, besides the usual assortment of sockets/ratchets/extensions:
    • 10mm flex head ratcheting wrench
    • 7-inch diagonal cutting pliers, if you plan to reuse the factory hose clamps
    • 11" 90-degree bent-nose pliers to grab the PCV hoses
    • Picks and wire brushes to clean the valve covers after removal
  6. Notes:
    • If you're slow like me, budget a lot of time for this job. I did both the driver and passenger side valve covers. It took me 12 hours. Like I said, I'm slow.
    • This may be 07-specific, but there is indeed enough room to do both sides without jacking up the engine.
    • I did jack up the front of the vehicle to gain access underneath. The driver's side, front and middle bottom bolts are easier to access from underneath. The driver's side rear bottom bolt is actually easier to access from the top, but you'll need to use the flex-head ratcheting wrench. The passenger side can be done from the top.
    • I did not drain the oil, but recommend using a rag to soak up as much oil from the bottom of the heads as possible after removing the valve covers. This will give you more time to apply silicone and reassemble before the oil starts seeping out again and ruining your seal.
    • On the driver's side, you definitely want to remove the air pump (removing the fuse box cover and fuse box cover bolts gives you more room).
    • It also helped to remove the fuse box bolts (but again, not the fuse box itself) to let you push aside the battery cable when reinstalling the driver's side valve cover.
    • Definitely remove the oil filler tube before removing/replacing the valve cover gasket.
    • Practice the re-install of the valve covers before you apply any silicone or install the new gaskets. Figure out where you're going to hold the valve cover and how you're going to get it in place without disturbing the gasket.
So, um, yeah. Plenty of videos and guides out there for the overall job. But hopefully there's info in here that can help save others a bit of time.
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