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2017 Outback Engine Rattling Noise Upon Start

I’m curious how the engine ran well enough to be shifted into gear without stalling with the vacuum leak caused by a missing piston.

I don’t have all your answers, I was there when he removed the heads and the piston was not there. There was a big deep grove down the side of the piston wall from the rod. It was under warranty, but this was before lemon laws and the dealer “couldn’t find anything wrong”.

I also didn’t follow up to see what the outcome was between him and the Buick dealer. I don’t know why he even took delivery on it with it making that noise, I wouldn’t have even driven it off the lot.

A V-8 will run pretty good with a quarter-sized hole blown in one piston dome (seen it). A big airplane radial engine will run with one “pot” (cylinder) completey blown off!


back in 90-s, one my far relative bought a new small 4-cylinder car back in Eastern Europe, which was “kinda off, low power” from the start

after few months of complaints to dealer, he went to his fellow mechanic and upon head removal they found exactly the same: missing piston :slight_smile:

in his case, rod was missing too and they simply added missing parts and it was running great after that

at that point they did not care about warranty or such (when your entire car is under $4K)

Read my above post. Mid 70s US vehicles were the worst I had ever seen. QC was obviously non-existent. Working at a “Gonorea Motors” (GM) dealership I had the pleasure (NOT!) of dealing with them. Due to a phony “tire shortage” they came with a spare wheel. At least the dealership where I worked purchased and mounted cheap spare tires. It seems the manufacturer’s policy was get it to a dealer and have problems fixed at a discount for the manufacturer (70% of normal shop labor rate).

The 4.0L Jeep I6 engine had the oil filter mounted upside down but used a stand pipe to prevent oil from draining out when the engine was shut off. It seemed to work well. I seem to recall that Perkins diesels used a similar design for the same purpose. How is it that Subaru wouldn’t see the benefit of a stand pipe and incorporate it into the filter mount.

Hopefully it wasn’t a metric transmission design. Metric transmission with a 9/16 " wrench included, what a waste … lol … good story OK! :slight_smile:

This post got the attention of the CarTalk staff. As you may know, many of us at CarTalk are current and past Subaru owners and many of us are fans of the brand. We dug into this topic a bit and got some insight from Subaru of America. Here is what we came up with: “Subaru Engine Sounds - They All Do That”

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Hmmm…That is interesting, and I guess that it is plausible.
However, I’m just glad that my 2011 Outback (6-cylinder) does not exhibit that noise.


I have a 2017 Outback also
And it does the same as yours
Is it normal.
Well yes and no
Its going to happen because Subaru screwed up.
They have the oil filter at the top of the motor and its upside down. This allows the oil to drain out over a period of time.
Then on startup the oil pump has to refill the filter before the engine gets any oil pressure.
This is a common sense No NO to do to any engine.
Most of the noise you hear is the timing chain rattling because there is no oil pressure until the filter is re-filled. THEN the tension-er will extend and tighten the cam chain.
This is a rookie mistake.
But like all the Subaru’s that burnt oil and the dealers were telling everyone that it was normal when it was Not.
SUBARU NEEDS A SWIFT KICK for such a rookie mistake.
Its nice to see they dont burn oil any more but now we have a motor that is starved for oil upon start up. Because over a period of hours the oil filter empties out.
All we need is an adapter that will let the filter hang face up so it cant empty out …

I tried heavier oil… No difference
I tried different filters No difference

If you take the filter off after the car has set over night there will be no oil in it.
Even the back flow valve in the filter will not stop the filter from leaking out over night.
So dumb.

In Subaru’s defense, it could be said that every car manufacturer is guilty of those WTH were they thinking moments.

I’m not sure I entirely agree with you about placement of the filter as being a/the problem

Mercedes-Benz has had oil filters mounted at the top and upside down for years, both cartridge and spin on, to name another manufacturer, and that’s not caused the problems discussed about here

In fact, one of my cars right now has just just a design and it has caused absolutely no problems

And I’ve been a professional mechanic for decades, so my sample size is huge

So I would not agree that simply placing the filter upside down is “screwing up” . . . to use your language

Don’t take this the wrong way, but I’m not sure why somebody decided your post was the “solution”

I don’t think you solved it

I’m just calling it as I see it


I strongly suspect that a rattle upon startup has a cause other than the filter placement.

I’ve heard countless times that Filter X or whatever will cause a valve lifter rattle upon startup for example. The problem is not the filter; it’s a lifter bleeding off.

What about air-cooled VWs? They don’t even use an oil filter at all unless someone has added an aftermarket unit.

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Just curious, is the reason why they’d orient the filter like that to make it an easier job to replace? And wouldn’t it make a mess when removing it b/c all the oil would drain out and pour over the engine while it was being removed? Or do they have a solution for that?

It doesn’t make a mess. I don’t know why, but it just doesn’t.

Edit: my guess is that as you unscrew it and it breaks the seal, the oil rushes out but immediately drains back into the engine. I can’t actually see it doing that as the filter blocks my view until I get it completely unscrewed.

considering it only does the startup rattle after sitting over night. And i took the filter off one morning and there is absolutely no oil in it. And that means there will be NO oil pressure to any moving parts until the oil pump refills the filter.
An oil filter at the top of the engine and upside down so it can drain back is the dumbest idea ever.
This rattle has nothing to do with warm up time. Temp outside or oil temp.
Try this … Let the car sit over night. Start it in the morning and if it rattles turn it off .
So what we have done is start the car and it ran for 2 or 3 seconds. then shut it off.
OK restart and it will not rattle on the second start. you can wait an hour and it still will not rattle. Because the filter is now full of oil and all the parts will get oil pressure right away.
Not rocket science just the not so common (common sense).

I have had cars that had the oil filter mounted on the side of the block rattle after sitting all night. Simple cure was to install a better oil filter with a drain back valve.
In Subaru’s case and the filter being upside down even good filters leak out over night.

Now I keep hearing the BS story that most wear occurs on startup. Because it takes time for oil to reach all the critical areas of the motor. And this is on cars that dont rattle do to lack of oil pressure. And if this startup wear is true!!! Then how much wear is going on in the new engine with an empty oil filter every morning???

Also who said my answer was the cure???
This is my personal opinion based on 42 years in the industry.

Other vehicles that have an upside down filter mounted high in the engine bay my have a drain back valve built into the oil line. (one way valve) and that may be why they dont rattle.

Another reason for the rattle may be that Subaru in all there - or Lack Off ingenuity may have forgot to put a ratchet assy on the tension-er for the cam chain so when the engine is shut off the chain stays snug. This would stop any chain rattle at startup due to the time it takes to refill the filter after hrs of sitting.

I know a lot of people love Subaru but they have made some blunders in the past. The massive oil burners that they wouldn’t stand behind being a big one. Those engines had low friction rings installed. Great idea but they were so low friction they didnt wipe the oil off the cylinder wall good enough allowing oil to get past the rings. They should have been forced to recall all those engine because of the pollution they are causing. Not to mention the catalytic converter failures.
But Subaru said it was normal to use a quart of oil every 1000 miles or so. A sure it is !!! What BS

So you say why did I buy one ??
I found out they fixed the oil issue. I would never own a car that burnt oil like that…
And I didnt hear the start up rattle at the dealer…
And it was a 6 speed manual and all wheel drive. I would never have bought it if it only came in an automatic…

It doesn’t make a mess because the filter sits in a bowl that catches the oil and lets it drain back into the motor. Spooky part is any dirt in that bowl will get washed into the motor also… Trick is to clean around the filter before removing it. And yes they did it to make it very easy to do your own maintenance.
Changing the oil on this setup is very easy and can be done very quick with no mess.
So nice idea. But if I am right and this is causing the lack of oil pressure start up rattle …
Then maybe not such a good idea…

OP said your answer was the cure . . . he placed a green “solution” check mark next to it

Glad to hear you’re another industry veteran . . . we need more of you on this website

Anyways, you have some interesting ideas, as to other causes

As for engine oil consumption, yeah, I’ve heard that before

When I worked at the Benz dealer, there was an engine family which guzzled oil like it was going out of style. Yet the manufacturer claimed engine oil usage of up to 1qt/600 miles was acceptable. There was even a “piston ring break in procedure” which paid approximately 1 hour. It consisted of driving the car at varying rpms at freeway speeds for 1 hour. Only after that was performed was the mechanic allowed to start the oil consumption test, which almost always came back as acceptable, even though the engine was using a lot of oil, same as before.

When we told the customers they needed to check their engine oil level in between services, that didn’t go over too well. Considering the service intervals were sometimes 13000 miles, just imagine the amount of oil added in between services . . .

And by the way, that engine family had numerous other mechanic problems which plagued it for its entire existence.

As did the 7 speed automatic transmission which sat behind it . . .

Not good when both a manufacturer’s bread and butter engine AND its bread and butter transmission are both pure garbage

As for “start up rattle” . . . I’ve got another good one for you

At one point I was diagnosing a start up rattle, actually, it might have been a constant rattle. It’s been quite a few years. This particular vehicle had a crate engine installed recently, a crate engine bought from a Benz dealer, as a matter of fact. It turned out the rebuilder had gotten a little carried away with rtv when resealing the timing case cover, which blocked off an oil passage to the chain tensioner. After cleaning it off and doing it the proper way, all was well again.

A few days later, one of my coworkers was struggling with a rattle. My shop foreman told me that it sounded like the problem I had, and I should go over and take a look. I advised the mechanic to take off the timing case cover. Sure enough, the oil passage to the chain tensioner was blocked off by rtv. And this car also recently had a genuine Benz crate engine installed, same engine as the one I had been working on. I suppose it was the same rebuilder, and he pulled his stunt on the same day. Maybe he’d gotten the cold shoulder the night before . . .

A reminder of how high that oil filter is:


Looks like the “timing belt” engines didn’t have this high oil filter: