Rattling sound from engine

neilaldrincruz · Oct 9, 2015

Background
From basically the start of the life of my 2013 Subaru Outback 2.5i, occasionally I would hear a rattling sound coming from my engine.
- it normally comes when my car has been running for at least 10 minutes
- it can occur from acceleration-from-a-stop
- it can occur even on acceleration-on-highway
I'm normally pressing light/medium on the throttle.

Diagnosis
Subaru dealership service listened to the problem; they advised I should change my brand of gas (note: not the octane level from 87).
- I had been using QT gas [quite popular in Arizona]
- I switched to Chevron gas [popular in Arizona and California].

I notice the rattling has gone down quite a bit; but it still happens from time to time.

1. Has anyone else experienced this problem?
2. Does anyone have any advice?

Currently at about 73k miles on my vehicle; averaging about 34k per year.

Thanks in advance for any feedback.

patrikman · Oct 9, 2015

This has always been happening?

Have you checked all heat shields? Brackets for all engine accessories and wiring?

neilaldrincruz · Oct 9, 2015

patrikman said:
This has always been happening?

Yes

patrikman said:
Have you checked all heat shields? Brackets for all engine accessories and wiring?

I'll suggest that on my next oil change.

Thank you for the quick feedback

rustbeltah · Oct 9, 2015

The heat shields will rattle and can sound like the end of the world on acceleration, often a bolt has rusted out or gone missing. When cool you can get under and check them pretty easily. Otherwise not the subaru piston slap? That is pretty common but not a rattle.

neilaldrincruz · Oct 9, 2015

Thank you for the feedback for the heat shields. I'll see if I can secure them on a cool afternoon/evening.

clemsonguy · Apr 19, 2019

Sorry for responding to such a late thread but did you ever figure out what the rattle was? Seems like I might have the same rattle on my 13 outback.

GoliathZr2 · Jun 12, 2019

Mine is doing the same thing. I looked under the car the bolts for the heat shields are still there. Very rusty bit still there.

1 Lucky Texan · Jun 12, 2019

gas is extremely unlikely to be the issue - and a dealership can retrieve knock events and timing , etc. so, they should know better.

Now, IF a knock sensor is bad, high octane fuel 'may' improve the symptom, but on a 4cyl engine it is not a a 'fix'.

Some 6 cylinders need high octane.

Biebs · Jun 13, 2019

My 2 cents

Being in Arizona doubt you have rusty heat shields.
Does this seems to happen in hot weather??

I would go to a 5-30 motor oil

Rattling sound from engine

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