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'05 Outback, 2.5L, M5
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Discussion Starter #1
Hi,
Had spark plug tube and valve/rocker cover seals changed at ~ 114k mi due to oil seepage on plugs and plug wires.
Checked plugs during most recent oil change @ 133k mi, and the plugs and wires are oil-saturated again.

Granted, not as bad as prior to first replacement, but still! I'd think replacement every ~15k mi/ annually to be a bit excessive.

Anyone else have any feedback regarding expected lifetime/replacement interval on the rocker/valve cover & spark plug tube seals?

(Vehicle is '05 OBW 2.5L SOHC w/ MT)

Thanks!
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
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12,307 Posts
What brand did you use?
 

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2008 OB Limited 2.5i, Portland OR USA
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6,358 Posts
I'd think replacement every ~15k mi/ annually to be a bit excessive.

Anyone else have any feedback regarding expected lifetime/replacement interval on the rocker/valve cover & spark plug tube seals?
It sounds like the valve cover gasket replacements were not done correctly, or you have another source of oil leakage somewhere.

The spark plug tube seals are not the cause of the problem, they are just a casualty.
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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26,318 Posts
any RTV / silicone type sealant put on the valve covers in typically prescribed places at the time?
 

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'05 Outback, 2.5L, M5
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Discussion Starter #5
Hello,
To answer the questions,
12-01-2017 02:02 PM
AWDFTW What brand did you use?
12-01-2017 04:16 PM
eagleeye any RTV / silicone type sealant put on the valve covers in typically prescribed places at the time?
Unknown. I had the service performed at a recommended, independent Subaru specialist.
Prior to the repairs, I requested genuine, Subaru OEM-only replacement parts. I did get the old parts removed from the vehicle, but I suppose there's no way to know for certain if genuine/OEM Subaru parts were used for certain.

12-01-2017 03:49 PM
johnre
Quote:
Originally Posted by elcapitan View Post
I'd think replacement every ~15k mi/ annually to be a bit excessive.

Anyone else have any feedback regarding expected lifetime/replacement interval on the rocker/valve cover & spark plug tube seals?
It sounds like the valve cover gasket replacements were not done correctly, or you have another source of oil leakage somewhere.

The spark plug tube seals are not the cause of the problem, they are just a casualty
.
>Yes, this is my concern, also. No other external leaks that I can detect.
Frustrating as if I had known I would need to have re-done anyways, I would have just attempted to perform the repair myself. Originally I thought I was going to save time/get a quality job by having it done professionally, vs. doing it myself.

The spark plugs are difficult to photograph, but I will try to post some comparison pictures soon, nonetheless.
IMO, the "newer" plugs look worse than the plugs I removed at ~90K of unknown mileage!
 

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2008 Outback 2.5
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959 Posts
Did the plug tubes look anything like this?




And did the plugs look anything like this?
Clean on the inside and gunked up with oil on the outside:



If yes, then it is the tube seals. Not too difficult to replace, the valve cover bolts are the only things you need to remove that are difficult and only the ones closest to the frame which are a pain to get to. Once the covers are off, you don't even need to pull them completely out to replace the tube seals or the VCG which is a good thing because I could not get one out to save my life. I simply replaced the gasket and reattached the valve cover. A ratcheting box wrench really helps.
 

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'05 Outback, 2.5L, M5
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12 Posts
Discussion Starter #7
Hi rsrocket1,
Yes! Exactly for the external oil "above" the plug sealing washer.
Not sure what the mileage on your plug there is, but mine looked worse than that when I pulled them, much to my dismay.

Thanks for the mini-how to. Although I have now done a good bit of DIY work on this vehicle, the tube seal replacement initially had me intimidated, which is why I opted to have the garage replace them.
 

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OBW H6 VDC, Tribeca, XT6
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They should certainly last longer than that - but they are prone to failure. They may have been inadvertently over tightened rather than using a torque wrench. I rarely use a torque wrench but I would on these, and many subaru VCG's given their propensity to leak.

Can you stop by the shop and ask them what they think?

Clean mating surfaces well.
Light coat of oil on all seal surfaces that will touch metal
install carefully
tigthen properly.
 

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2005 OBXT Limited, VF37, STI intake, 5MT
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Did they actually replace the tube seals with the gaskets (which would have been in your pile of old parts)?

And if the valve cover gaskets are not torqued in proper sequence to avoid distorting the tube seals, that can also happen.

However, it's possible the tubes themselves have become unseated and are allowing oil to weep in from around the plug itself rather than trickle-down. If the top of the tube near the valve cover is bone dry (as is the top of the spark plug wire), you don't have leaking tube seals.
 

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'05 Outback, 2.5L, M5
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Discussion Starter #10
Thanks for the additional tips, guys.
I will pull the plug wires again, and re-check the exact locations of the oil leaks, try and grab some pics.
I know that the seals were replaced as the old, hardened ones were included in the "old parts" box after the job was done.

Re: the shop where the work was performed:
I live in South Central Pennsylvania (USA), and had the work done by a shop recommended to me by my aunt while I was on a summer vacation (2016) in Maine. In retrospect, not the most ideal, but I trusted the recommendation of my aunt, the price was reasonable, and a warranty was included (1 yr/30k miles, I think). So I am over on both the time, and the mileage at this point, of course.

At this point, I will likely attempt the next go at it myself. (Have good torque wrenches)
Although, I don't think it's unreasonable to expect that the tube seals/VC gasket OUGHT to last at least as many miles until the next timing belt service.
 
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