Under the valve cover - 2002 Outback H6

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Apr 27, 2014
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SD - South Dakota
I had a valve cover go WiFi on me in my 2002 Subaru Outback H6 so I did an R&R on the affected side. It was leaking profusely with a steady stream coming out so it had to be parked until it was fixed.

Anyway, while doing the gasket I snapped a couple of pictures just for fun.

2002 Outback H6. 197,000 miles. Maintenance has varied over the years that we have had it. We’ve owned it since 2008 and 65,000 miles. I used to change every 5000 with trop artic 5w30. Since about 140,000 miles I switched and started using high quality synthetic at 10,000 OCI. Usually Mobil 1 of some variety since the oil analysis always came back good. Currently using Castrol edge (gold bottle) at the same OCI and will continue to do so until it is ready to move to the big parking lot in the sky.

I’m satisfied with what I see and have no concerns. Just like to share. Open to any and all comments as well.

For anyone curious, changing valve cover gaskets on an H6 sucks. We did the one side only and did the plugs on that side while we had access. All in it took about 5 hours. Almost 2 of those were spent trying to figure out how to get the coil packs out of there. Book time for the gaskets is 2.7 hours. Book time for spark plugs is 3.1. Yeah, they are a pain.

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The outback in my signature needed a rear main seal, spark plugs, and valve cover gaskets. I'm 95% certain it's easier to pull the EZ30 engine than to try and do them in the car. It took me ~2.5 hours to pull the engine, 2 hours to put it back in, and you don't even need to disconnect the AC.
 
really Never short trips in this car. When the wife drove it every day it was 35 miles one way to work and then back home.

We did give it to her mom and dad for about 3 years. They short tripped it, but I don’t think they put on even 10,000 miles in that 3 years.

Now it sees daily duty under my right foot. And Arduous 30 mile drive in to work dropping off kids every morning and an easy 25 mile interstate drive home. Then once a month I have to drive 230 miles one way to a meeting for work and then 230 miles back home in the same day. That whole trip is at 2800-3000 rpm since the car has pretty short legs.

The dark stuff in the picture looks much worse than it did in person. It was very thin and very soft. I could have easily cleaned it out with some brake cleaner and a towel, but I just didn’t see the point. So I slapped it back together the way it was.

As to this engine being hard on oil, I don’t think it is particularly. It runs a lot of rpm but the oil analysis at a 10k OCI always looked really good. But I’m not an expert on this engine or Subarus in general.
 
The outback in my signature needed a rear main seal, spark plugs, and valve cover gaskets. I'm 95% certain it's easier to pull the EZ30 engine than to try and do them in the car. It took me ~2.5 hours to pull the engine, 2 hours to put it back in, and you don't even need to disconnect the AC.
It is easier to pull the engine to do a valve adjustment on the EJ25 too.
 
Trop Arctic Oil is not a quality oil, which is probably how it started with the sludge and varnish, and 10K oci's with a good synthetic didn't help. Combined and there lies the reason for the varnish and sludge imo. 10K OCIs are not for everyone.
 
With your OCI, I wonder why the sludge and varnish? Is this engine known to be hard on oil? Was is short tripped often?
I don't see any sludge, do see a fair bit of varnish on the valve cover but the engine doesn't look awful, I'd say that is more staining than varnish on the head/cams.

Looks like that top section of the cover is near the timing chain and there's a cover of some sort so it likely gets no real flow through the area. Perfect spot for contaminants that are falling out of suspension to locate themselves and then never get cleaned off (no flow).
 
@OVERKILL I was looking at the few areas with thicker black buildup. Is this sludge or thick varnish? It's the falling out of suspension I'm curious about. With the OCIs, I wouldn't think this would be a problem.
 
This is probably typical of the EZ30s, and probably the only real concern as well (leaky VC seals). I’m sure there’s been at least a few failures over the years, but I personally know of no EZ30/33s or the 3.6s that have ever needed anything more than valve cover gaskets and the occasional water pump. Really, other than somewhat dismal mileage due to the boxer layout (especially when cold), IMO these things are about bulletproof due to closed decks and timing chains. Keep the dipstick wet and they just keep running…

OP thanks for pics and happy motoring!
 
Trop Arctic Oil is not a quality oil, which is probably how it started with the sludge and varnish, and 10K oci's with a good synthetic didn't help. Combined and there lies the reason for the varnish and sludge imo. 10K OCIs are not for everyone.
Really you think Trop Arctic is to blame !
Where did you get the info on it not being quality oil !
 
Good job on the job, OP! The EZ engine is NO cake walk to service, nor is any DOHC Subaru for that matter. EJ, EZ, FB, they're all a pain to service when it comes to the cylinder heads.
 
Short tripping in South Dakota cold weather could lead to the varnish seen in the pics. For 200,000 miles it doesn't look too bad. I'd like to think my Honda's engine is clean and shiny under the valve cover, but since it operates in similar conditions as the OP's I might see the same thing when it's time to adjust the valves.
 
@OVERKILL I was looking at the few areas with thicker black buildup. Is this sludge or thick varnish? It's the falling out of suspension I'm curious about. With the OCIs, I wouldn't think this would be a problem.
I think that's heavy carbonaceous material in varnish. I think this was likely formed earlier on in the vehicle's life when it was run on poorer quality oils and due to the location, there's no way subsequent higher quality oils could clean it up. This explains the contrast in appearance between these areas and the ares that receive good oil flow on the head and cams.
 
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