[Droolguy]

The Subaru shop that sold me the car swears this is normal and the explanation they gave that it takes a second to lubricate on the first start due to the engine design. Never had a boxer before and sounds believable so I accepted the explanation.

But less than 50 miles after purchasing the car the air pump system throws a code for a $1-2k engine repair and I no longer trust them. The standard "It never gave us a code, don't know what your talking about, but we can fix it.".

This shop is locally trusted and has good reviews, but I am beginning to think that may just be because they are really good at explaining away things and covering stuff up. The chances of a car magically needing a major repair 50 miles after purchase, when the car has 180k on it, is basically like winning the lottery while being struck by lightning. So either I am insanely unlucky or the shop is hiding things.

The first start of the day and only the first start, for around 1-2 seconds, the engine knocks very loudly (enough that it can clearly be heard from inside the house, sounds like a diesel starting), and then goes away almost instantly. Will not happen again unless the car sits for several hours.

This is not piston slap, I know what that sounds like. It did it before I bought the car, then as a prepurchase agreement the same shop did a complete timing/idler replacement since the sound was similar to videos I found of tensioners failing. Still did it afterwards and at the time I trusted the shop so I decided to go with it and accept their explanation.

Is this normal?

 

[RyanT]

Some noise on startup is normal. Might help if you posted some good audio/video.

 

[Droolguy]

I figured as much so I had to wait until the car had been sitting for a few hours so I could get a video of it.
https://drive.google.com/open?id=16S8TlN681hJ3W0A3Ic18PRz8oxeGZ1NL

 

[poffer]

That kind of rattle on start up is often a sign of worn big end bearings. Has the engine been run “cold” for a while (i.e. thermostat permanently open)? Or has it been run low on oil or with too thick an oil?

If it is big ends, you can sometimes check by running the motor at around 3k rpm and varying the throttle up and down a bit (hard to explain without showing you). You then can hear the rattle again as the engine picks up from the overrun.

Good luck and I hope I am wrong and it’s something else.

 

[Droolguy]

So far I have been unable to replicate the sound once it stops after starting the car, revving the engine and holding between 2-3k and varying the throttle inputs does not give me any indication of rod knock.

 

[sdub]

What oil do you use?

0w-30 will flow faster on cold starts and you may want to change to see if it makes a difference.

There are some awesome cold flow comparrisons on youtube.

 

[Galager]

What kind of oil filter is on there?


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[Scooby24]

Mine and others have had the same symptoms. Mine was a new NTN with timing belt kit. Had to replace it...used an OEM tensioner(also NTN but slightly different design than the aftermarket one) The hydraulics get stuck temporarily when sitting long enough and produces a god awful knocking noise as the tensioner smack against the block. Then suddenly it will stop and takes another long period with no start to do it again.

To rule out oil do an oil change with amsoil SS 5w30. Don't screw around with other stuff just go right to the amsoil.

 

[Galager]

I ask about oil filters, because a certain orange one may not have the proper valve in it and allows oil to drain back when sitting for extended periods of time. I learned about that the hard way on a Nissan. It would be oil starved when first starting. I stick with OEM filters


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[Scooby24]

The EJ's oil filter is under the engine so the oil will not drain out. FBs and FAs need to take that into account but not EJs.