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Old 05-12-2018, 10:43 AM   #26
Charlie-III
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I have an ME background, yes, I like figuring things out.
I also have decades of plant maintenance and field service. I sometimes go by, "don't fix it if it's not really broke".
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Old 05-12-2018, 01:45 PM   #27
Elbert Bass
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Yup, definitely rear cam caps/rocker cover in the photo - can't speak to the other side without seeing.
In the early FB20 you had poor sealing from factory. TSB 02-130-12R noted leaks from where timing chain cover meets left and right cam caps (I've seen more of these on right bank - conveniently above A/F sensor), leaks where front cam caps meet cam carrier, rear cam cap/carrier mating, rocker covers. It also mentions cam carrier/head mating leaks but I have never seen one of those.

Funny thing - part of the oil consumption test is noting oil leaks. You are not suppose to perform a consumption test on an engine with active oil leaks until the leaks are resolved. Although you don't remove cam caps to replace a short block I fix them if leaking to CYA - nothing worse than trying to explain:
"Yes, we performed an oil consumption test, had your engine out for oil consumption resolution but no, we did not tell you you had an oil leak before we started the repair. We did not make an effort to fix the leak - even though it would have only taken 5 more minutes to resolve during the short block replacement."

I would not worry about pulling the rear caps under load. You can unload the camshafts if you like - set crankshaft to TDC #1, then turn crank shaft 90 degrees clockwise. That position unloads the right bank camshaft. Turn a further 180 degrees clockwise and you have the left bank camshafts unloaded.


Quote:
Originally Posted by CosmoTheCat View Post
I'd say part #7 in the cam cap pic is the one.

In an ideal world, you're right - they'd never leak from the factory.
But that's clearly not the case. There was a recall on sunroofs back in 2010 or 2011 because the machine at the factory didn't do it's job gluing the glass down.

Anyway, if you're pulling the valve cover, I'd go ahead and pull those rear cam caps too. Clean them off and glue them back down. I guarantee there isn't a tech on the planet who looks at that bead spec and takes it seriously. There's literally no way.
Subaru now has curriculum in engine class about sealing. You take previously sealed aluminum jigs that have 2 flat and 2 channeled mate profiles. You clean per Subaru prescribed cleaning methods. Then you are given a tube of Fujibond and instructed to seal 1 of each profile with a 3 mm bead and the other two with a 5mm bead. Before you mate the jig instructor measures your beads so you can see how much you are using. Then you mate and bolt the jig together for the next class to clean. Everyone uses too much.
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Old 05-13-2018, 03:21 AM   #28
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I'm in the "my car doesn't dare to leak" camp.

Hell, I've got every leak on my 20 year old diesel truck sealed up, except the slip yoke that I need to replace. The crank vent drips a few drops, and that bugs the crap out of me.

My 22 year old Subaru doesn't drip.

That's good stuff on the new class segment. Really it needs to get some oil on it and a few hundred heat cycles.
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Old 05-15-2018, 06:55 PM   #29
Rymar
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So, I replaced the rocker cover seals two days ago, let the sealant cure overnight, and have now run the car through 4 drive cycles (at least 10min driving at full engine temp). Last one was 30 minutes of freeway driving.

No leaks! I know there are certain types of failures that could show up after 10 or 20 drive cycles (or maybe hundreds?) but I'm willing to declare a cautious victory.

I ended up not resealing the cam caps. I noticed that they had black sealant, even though the rocker covers had grey (presumably Three Bond 1217). The rocker cover was resealed after the short block replacement 3 years ago. So the cam caps probably have a factory seal. And the motor didn't leak during its first three years and 45,000 miles, so I thought why mess with it.

I noticed that the covers came off too easily in some areas that had sealant, as if the silicone wasn't adhered well.

This is what I found (one internal goober was about ready to break off):

https://i.imgur.com/HYRQo8B.jpg

I cleaned both the groove in the rocker cover and the mating surface meticulously, with only plastic tools, and then used throttle body cleaner to wipe both down. Inserted the new gasket into the cover, and then applied a 3.5 mm bead right down the middle of the gasket. I've seen a couple of FB20 teardowns where the sealant is applied to the cam carrier assembly (the mating surface) rather than to the new gasket while it is in the cover, but that's not what the manual says. I also applied it only in the areas where the manual drawing indicates.

They say to get the cover on and tightened down within 5 minutes, but that is hard to do. Also note that the torque spec on the bolts is only 4.7 ft-lb.

Here are the "after" images (there is a bit of grime still on the heads and chain cover, but no fresh oil):

RH:
https://i.imgur.com/q30XABG.jpg

LH:
https://i.imgur.com/HTBOmkO.jpg


A few more details, for anyone considering this work.

The lower rear bolts on each rocker cover are hard to reach; a small 10mm wrench is all that will fit.

Oil will dribble out of both heads, so be ready with towels. I stuffed a few paper towels into the heads to stop the dripping.

Replace the spark plug tube seals; the old ones felt stiff. I don't think they were leaking. I also replaced the lower right camshaft position sensor O-ring, but I don't really think that was leaking either.

Also, you don't need to remove the exhaust, as the manual says. Removing the battery and air intake box and tube allows plenty of access.

Here are the parts required (the prices shown are as of 5/8/2018, from subaruparts.com). Probably didn't need to buy 4 of the camshaft position sensor O-ring seals... I would also use 3M 08672 instead of the crazy expensive Three Bond.

Part_Number_____Part_Name__________________Price__ Qty__Total
SOA868V9610_____Three_Bond_1217H___________$38.74_ _1___$38.74
13272AA170______Valve_Cover_Gasket_________$15.80_ _1___$15.80
13270AA240______Valve_Cover_Gasket_________$15.80_ _1___$15.80
13099AA050______O_Ring_Camshaft____________$2.73__ _4___$10.92
10966AA041______Gasket_Spark_Plug_Pipe_____$2.38__ _4___$9.52
Subtotal:_________________________________________ _____$90.78
Shipping_(USPS_-_Parcel_(Standard_delivery)):__________$11.39
Total:____________________________________________ _____$102.17
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Old 05-15-2018, 11:00 PM   #30
Elbert Bass
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Color of sealant is irrelevant. The 2012 service manual specifies 1217G EVERYWHERE.
TSB 01-167-08R (Recommended Materials) indicates 1217H (dark grey) replaces 1217G and a suitable substitution is 3M Ultrapro High Temp Silicone 08672 Black.

Have had no problems using 1217H on ALL Subaru engines in ALL applications.
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Old 05-15-2018, 11:27 PM   #31
2slofouru
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The most important part of this type of reseal is to COMPLETELY remove ALL traces of any oil film where the adhesive is applied. The lower areas are difficult because oil will continue to try and drip down on the cleaned areas. The sealant will not adhere to the metal, even if there is one molecular layer of oil. Many times the jobs that come from a dealer and end up leaking aren't cleaned properly, some techs just get it done asap and aren't worried about comebacks. You can use anything from hondabond to toyota fipg black and if it's cleaned properly it won't leak for many years. Even some factory workers neglect to clean oil film off sufficiently for the sealants to adhere to the metal.
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Old 05-16-2018, 01:09 AM   #32
Rymar
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Quote:
Originally Posted by Elbert Bass View Post
Color of sealant is irrelevant. The 2012 service manual specifies 1217G EVERYWHERE.
TSB 01-167-08R (Recommended Materials) indicates 1217H (dark grey) replaces 1217G and a suitable substitution is 3M Ultrapro High Temp Silicone 08672 Black.

Have had no problems using 1217H on ALL Subaru engines in ALL applications.
Good to hear. The 1217H looks like high quality stuff; just 4x as expensive as the 3M.

I only noted the black sealant on the cam caps because it seems to indicate that they were not removed and replaced during the short block replacement; otherwise the sealant would probably be grey because that's what the dealership tech would have used.

So not better or worse, just a little evidence as to what the history was.
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Old 05-16-2018, 01:26 AM   #33
Rymar
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Quote:
Originally Posted by 2slofouru View Post
The most important part of this type of reseal is to COMPLETELY remove ALL traces of any oil film where the adhesive is applied. The lower areas are difficult because oil will continue to try and drip down on the cleaned areas. The sealant will not adhere to the metal, even if there is one molecular layer of oil. Many times the jobs that come from a dealer and end up leaking aren't cleaned properly, some techs just get it done asap and aren't worried about comebacks. You can use anything from hondabond to toyota fipg black and if it's cleaned properly it won't leak for many years. Even some factory workers neglect to clean oil film off sufficiently for the sealants to adhere to the metal.
So, one advantage of not continuing the sealant around past the lower corners of the rocker cover seals, is that on the lower edge, there is only the rubber seal against aluminum. This is also where an oil film could remain due to dripping oil, but it doesn't matter since there is no sealant.

I waited a few hours with the rocker covers off, and made sure that oil was not dripping out over the cleaned surface, before doing the installation. One advantage of working on it yourself is that there is no time pressure. I also waited for an overnight sealant cure before starting the car, which I'm sure is not always possible for a professional tech.

Thanks again to everyone for all the feedback and advice. I really appreciate the depth of knowledge on this forum.
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Old 05-16-2018, 09:42 AM   #34
Charlie-III
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Glad you got it done.
Fingers crossed it remains dry.
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Old 05-17-2018, 03:08 PM   #35
Angelus911
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Quote:
Originally Posted by Rymar View Post
So, one advantage of not continuing the sealant around past the lower corners of the rocker cover seals, is that on the lower edge, there is only the rubber seal against aluminum. This is also where an oil film could remain due to dripping oil, but it doesn't matter since there is no sealant.

I waited a few hours with the rocker covers off, and made sure that oil was not dripping out over the cleaned surface, before doing the installation. One advantage of working on it yourself is that there is no time pressure. I also waited for an overnight sealant cure before starting the car, which I'm sure is not always possible for a professional tech.

Thanks again to everyone for all the feedback and advice. I really appreciate the depth of knowledge on this forum.
Good walkthrough, I have a similar issue, but can't see taking it apart as its mostly a cosmetic thing for me. I plan on just using some RTV around where its leaking to slow it down.

Curious, Rymar, did you have the oil leak prior to the new short block? For me, it developed shortly after the new shortblock was installed.
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Old 05-17-2018, 05:53 PM   #36
Elbert Bass
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Quote:
Originally Posted by Rymar View Post
Good to hear. The 1217H looks like high quality stuff; just 4x as expensive as the 3M.

I only noted the black sealant on the cam caps because it seems to indicate that they were not removed and replaced during the short block replacement; otherwise the sealant would probably be grey because that's what the dealership tech would have used.

So not better or worse, just a little evidence as to what the history was.
Yeah, it is kinda strange the factory uses a different sealant and then specifies a substitute in the field. At least 1217H comes in short 150 gram tubes.
The service procedure for short block is to remove the cam carrier as an assembly so normally cam caps would not be removed. Of course in your case...
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Old 05-17-2018, 09:15 PM   #37
Rymar
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Quote:
Originally Posted by Angelus911 View Post
Good walkthrough, I have a similar issue, but can't see taking it apart as its mostly a cosmetic thing for me. I plan on just using some RTV around where its leaking to slow it down.

Curious, Rymar, did you have the oil leak prior to the new short block? For me, it developed shortly after the new shortblock was installed.
No, there were no oil leaks before the short block replacement (car was 3 years old). It seems pretty clear this is a workmanship issue. I didn't notice any leaks for at least the first year afterwards, but I think they were pretty slow.
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Old 05-18-2018, 01:57 PM   #38
Rymar
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First, the good news: the rocker cover seals are dry 5 days later; including all 4 lower corners, which is where there were leaks before.

But, it turns out that the chain cover (timing cover) is seeping oil. During the short block replacement, the same guy who replaced the rocker covers (which leaked) replaced the timing cover (which leaks), and it's clear there is way too much sealant. It could be insufficient cleaning, so that an oil film was left on the sealing surface. Or maybe it was just wrong placement of sealant. Or maybe too much time between application and getting the cover sealed down.

Here is where an oil film develops after a day's driving (~2hrs engine running, 3 drive cycles). There is no additional seepage overnight, so this is definitely only happening while the engine is running.

https://i.imgur.com/h1josv6.jpg

Note that there is NO oil film above this on the right front cam cap. It's also not coming from the seal between the right rocker cover and right front cam cap. The oil seems to be coming right out of the chain cover seam.

Now, Charlie-III would clearly say "what is your fricking problem?. Is that really broken?", or words to that effect.

But we're about to take a 1500 mile trip to Portland, and maybe I just really don't like the smell of oil vaporizing off an exhaust pipe, even occasionally.

So, I'll decide later whether to reseal the chain cover. It can be done with the engine in the car (after removing the radiator), and the cover only has 37,000 bolts.

Here is the short term solution. The mini oil-pan is stuffed with oil absorbent mat, and before anybody freaks out, yes it is mounted securely, and no it's not going to catch fire: it is right next to a plastic connector and wire, and there is a heat shield underneath.

And yes, it's ridiculous...

https://i.imgur.com/9RqioFR.jpg

https://i.imgur.com/8hn7f1x.jpg

https://i.imgur.com/27EStCh.jpg
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Old 05-18-2018, 02:03 PM   #39
Charlie-III
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Engine oil diaper.......LOL.
Way more than I would do. But, your car and driveway. Points for a solution.
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Old 01-13-2020, 07:04 PM   #40
klimt
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This is affecting my 2012 Impreza. The actual TSB was hard to find so here you go:

https://static.nhtsa.gov/odi/tsbs/2012/SB-10093161-2280.pdf

Known issue with oil seepage from front camshaft cap, upper oil pan, and/or timing chain cover. The leak has damaged the O2 sensor.
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