Subaru top end noise diagnosis help!

Well, is it still the top if it's a flat engine? Side noise? Anyway.

I've been working on this '08 Forester (non-turbo EJ25) for a while now, fixing various leaks (there were a lot) and getting it ready to resell. The engine is now back together and running, but it has a concerning tick. It's loud enough to be heard in the car with the hood closed. If I listen to it with a mechanic's stethoscope, it sounds like it's in the valvetrain on the driver's side (cylinders 2 and 4). It's louder in 2, but can be heard in 4 as well. Bottom end is totally quiet, passenger's side is totally quiet so I don't think it's knock and I don't think it's valves making contact with pistons. I took a look with a borescope and the pistons look fine too. Compression is good (190ish) in 2. Not an exhaust leak or loose spark plug. Valve clearances have been checked and adjusted (twice, once when the engine was out of the car and it was MUCH EASIER) and again now that it's back in.

I really don't want to pull the engine back out and take the head off, but it seems like I'm heading that way. Anything else I should look at? I'm triple checking the timing next. I'm kinda pulling my hair out on this.

The EJ251 in my '01 Outback ticked very noticeably for the whole 60k miles I owned it. I adjusted the valve lash too, and it made no difference. It was a completely healthy engine otherwise. Without hearing it in person, it's hard to tell, but if it's the same noise, I'd call it a "they just do that" thing for Subaru flat 4s.

Heavier oil?  

Amazon 5w40 just $5 each

There's 10w50 out there too.

Our '08 Outback sounded similar until I did an unplanned engine refresh due to leaking head gaskets. We ended up having the cylinder heads cleaned up and I just assumed re-setting the lash after cleaning up the valve seats did the trick. The only other thing I could think of was it being related to the variable valve lift mechanism. 

Having owned a lot of EJ NA Subarus, a few of them have ticked some and seemed fine but I still don't think it is just normal for these engines. 

In reply to enginenerd :

Yeah, the reason that I'm losing sleep over it is that this is immediately after what I would call a light engine refresh - I basically pulled it to replace the head gaskets, resealed everything that was leaking (cam seals, rear main, etc etc) and did the timing belt/water pump. The heads were just machined and checked over by a reputable shop. 

Is it louder now than it was before?

Possible it's an exhaust leak at the head rather than a valve?

In reply to 02Pilot :

I was just thinking, Subaru exhaust manifold-to-head nuts like to stick on the studs, so the whole stud with the nut stuck on it comes out of the head when you remove them, and if you re-use them this way, you are 100% guaranteed to have an exhaust leak.

I don't remember it having this noise before I pulled it, but I can't be sure. I probably only heard it run for a single digit number of minutes before pulling the engine.

Exhaust studs were pulled, threads were chased and new gaskets were used on install. Several of them did come out with the nuts but I got all the nuts off and got them cleaned up before reusing.

 With a stethoscope, would I be able to hear an exhaust leak in the head? If I put the rod of the stethoscope on the valve cover I can hear the valvetrain and it sounds like that's where the sound is coming from.

Am I right in thinking that if the compression test is good I don't need to worry about timing? I might try setting lash on the tighter side of the clearances, I tried to set them dead on (.008 intake, .010 exhaust).

cmcgregor (Forum Supporter) said:

Well, is it still the top if it's a flat engine? Side noise? Anyway.

 

I think it's just "End Noise"...

Could it be a noisy injector? I'm not close to my car to see how hard it would be to pull a plug off one to see if that makes it go away.

Sinse it's a Subaru, it may be piston slap.  Does it get quieter as it warms up?

Did you check valve lash?  When replacing head gaskets it is recommended to do this.

Fixed it!

I failed to preload the spring for the variable intake valve lift system. I forgot that I had started to take the valve train apart on one side to replace valve stem seals before I decided that that was ridiculous since they were not leaking and I actually want to finish this someday. When I put it back together I didn't wind the spring around and set the retainer on its pin.

It's still a little ticky but it's more like normal "maybe try that valve lash adjustment again" ticky and less "something is broken" ticky.

Glad you found it.  Another Subaru noise is from when the exhaust valve guides slide out and hit the valves.  The returning valve pushes them back in but there is a noise that sometimes goes away after they warm up.

In reply to cmcgregor (Forum Supporter) :

Hey glad you found it!

Note to future amateur mechanics - this affects valve lash on the intake of #4 a lot, so if you make this mistake too, you need to recheck all your clearances.

It's running like a top now!

Anybody need a Forester?