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P0021 Intake Cam Journal Scaring


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Hi,

first time posting on subaru forums; tried almost everything I could find about fixing P0021 (Banjo Bolts, AVCS Solenoid, Timing belt, Intake Sprocket, Oil), but I would like some advise before I go and pull a head on my engine. I would feel really stupid pulling a head, and finding out I could have fixed it through something easier. I am not looking for a performance car, I am just looking for a car that will last as long as it can (I have tried to ask the Subaru subreddit for mechanic advise, but it seems like most people over there just buy new WRXs, and never really work on cars).

 

Situation:

I'm getting P0021 after rebuilding my ej255 on my 2008 OBXT (has 205,000miles on it, but it's still a beaut). Rebuilt because of rod knock, and rebuilt by myself. This code is the only problem I have had after the rebuild, and I have only put about 50 miles on the car since the rebuild (currently going through breaking period, so using non-synthetic oil and staying below 4000rpm). The car feels and sounds fine, although this is my first Subaru and i don't really know what is normal or not (also, the car died right after I bought it, so it sounded worse when I got it).

 

What I replaced in the rebuild:

OEM crankshaft, 2x OEM rods, OEM rings, Mahle main and rod bearings, Oil pump, timing belt kit, Melett vf46 turbo cartridge, Intake and Exhuast Valve seals, headgasket and seal kit, seals not included in seal kit, headbolts, bunch of hoses that were like rock. Heads were also honed. ALL Banjo Bolt Filters Removed during rebuild.

What I probably should of also replaced, but cleaned instead:

Oil Cooler, Oil pick up

(Most of the time put into the rebuild was spent cleaning block and heads with PSC 1000 solvent)

 

Replaced/Checked when trying to fix P0021:

- Checked Timing belt

- Replaced AVCS solenoid

- Cleaned/Rebuilt Intake Cam Sprocket

- Replaced with New Intake Cam Sprocket

- Changed Oil to 15w40 from 10w30

 

Things to note:

- All banjo bolts have been removed from the car during rebuild.

- Timing belt has not skipped any teeth.

- When running 10w30, I got the P0011 Code Once. After clearing codes and replacing Intake Cam Sprocket and changing oil, it hasn't showed up again. Would this mean oil is the problem?

 

During the rebuild I noticed some scaring on the Intake Cam Front Journal housing on the drivers side (bank 2). I didnt think much of it because Rod knock was the main problem, but now I think it is catching up to me. Maybe I'm missing something, but the Cam Journal is the last logical reason that I can think of for this problem. Maybe the Oil is clogged upstream of the AVCS solenoid altogether, but I pretty sure I did a good job cleaning everything.

When rotating the Cams into place to install the timing belt, the exhaust Cam always tries to snap out of place (like it should). However, the Intake cam with the P0021 code seems to snap back less easily. I think this is because of the scaring on the head causing additional friction on the intake cam. Should I try to polish it? (then I wouldn't have to remove the head). What I think is happening is that the oil pressure is dropping by bypassing the sprocket and jumping to the other side of the oil feed on the cam, and therefore not pressurizing the intake cam and preventing it from rotating properly.

 

https://legacygt.com/forums/attachment.php?attachmentid=285365&stc=1&d=1593307285

On the diagram above, I think the pressure is leaking between the Red and Blue oil passageways at the cam journal, or is just leaking into the head itself. Correct me if I am wrong, but the AVCS solenoid changes the direction of flow (Blue to Red or Red to Blue), and a leak between the two at the cam journal would prevent the proper oil pressure from reaching the Sprocket. There are no oil leaks on the exterior of the head.

 

I have not preformed any kind of oil pressure test, and I'm not sure where to do that either. I have a Craftsman OBD2 diagnostic tool, but I am not sure if it can do cam position monitoring on the subaru. I can't find a D25 head locally, so I would probably try to find a shop that is willing to aluminum weld onto the cam journal and then re-cut it (hopefully that is worst case scenario).

 

Lmk if you have any thoughts or questions!

AVCS.gif.bcfce3bce458f88d82c896db1a06f045.gif

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You really should have and still should change the oil cooler. Did you also clean any lines that oil flows through? Any contaminate left can destroy your new motor.

 

Did you replace the avcs cam gears? If not, that, or the avcs solenoids, is most likely the cause of your code.

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rhino6303

Ok ill look into the oil cooler (I tried to blow it out before rebuild, but I guess the cooler can't be cleaned).

When cleaning the halves and heads, I blew out everything with pressurized cleaning solvent, so I'd assume they are good. I changed the oil after the 20min initial break in idle and the 50mi, and each time the filter didn't have much shine or slivers of metallic to it. AVCS solenoid and intake cam gear are both brand new, so I would think they are both good. I test the old Solenoid with a 9V battery and the old one functions too, so the solenoid wasn't throwing the code.

Edited by TFabian
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You really should have and still should change the oil cooler. Did you also clean any lines that oil flows through? Any contaminate left can destroy your new motor.

 

Did you replace the avcs cam gears? If not, that, or the avcs solenoids, is most likely the cause of your code.

 

Have to agree with ^

 

You may want to move this thread to the 4th Gen forum to get more help.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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When installing the front cam cap did you confirm that no sealant got into the passages? This made me very nervous when I was assembling my motor. Looked just too easy to inadvertently clog. Do you have an accessport or another way to monitor the AVCS or OCV?
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When installing the front cam cap did you confirm that no sealant got into the passages?

 

I was Pretty careful when sealing the cam cap to avoid the oil passages. I guess I'll find out when I take the covers off. Won't be able to take off the covers for the next week or two, but once I do I'll post an update here.

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You may want to move this thread to the 4th Gen forum to get more help.

Ok. haha hopefully a moderator moves it because I have no idea how to move threads. I'll put on a new oil cooler when I remove the cam caps.

(Also, thanks for helping the forums. Saw your name so many times when doing research)

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Thanks,

 

Hey you may have this, but here's the service manual,

http://people.csail.mit.edu/ilh/vacation/

 

 

You could always route people to that new thread in the next post you make. Just say this one is closed and please see this thread ______ in the 4th Gen forum.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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