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2009 Forester
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5 Posts
Discussion Starter #1
Recently had my 2009 Forester head gaskets replaced, and while everything seems to be running fine, the engine definitely has a new distinct noise. Attached video. Not sure if people consider this noise a ticking or knocking, but certainly rhythmic. Mechanic who did work says it sounds fine to him. Not so sure and would appreciate thoughts. Thanks!

Mileage: 175k

Video: 09 Forester Engine Noise
 

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2006 Forester
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19 Posts
To me it sounds like valves weren't properly adjusted so you're getting valve slap. Typically a lot gets removed from the heads during a head gasket replacement so it can be cleaned and possibly resurfaced by a machinist, sometimes valves get removed and re-seated as well. It could have been something as simple as flipping the exhaust and intake valve clearance, they are different. These can be checked without removing the engine but it's still probably a 2-3 hour job with the right tools. If you've got feeler gauges, a basic socket set, and a 22mm socket, you can check and adjust these yourself.

Good info here: valve adjustment on 2.5 sohc - NASIOC
 

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2009 Forester
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5 Posts
Discussion Starter #4
To me it sounds like valves weren't properly adjusted so you're getting valve slap. Typically a lot gets removed from the heads during a head gasket replacement so it can be cleaned and possibly resurfaced by a machinist, sometimes valves get removed and re-seated as well. It could have been something as simple as flipping the exhaust and intake valve clearance, they are different. These can be checked without removing the engine but it's still probably a 2-3 hour job with the right tools. If you've got feeler gauges, a basic socket set, and a 22mm socket, you can check and adjust these yourself.

Good info here: valve adjustment on 2.5 sohc - NASIOC
So let's assume this is the issue, and nothing is adjusted. Is there a negative short-term or long-term effect? Or not a big deal?
 

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2006 Forester
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So let's assume this is the issue, and nothing is adjusted. Is there a negative short-term or long-term effect? Or not a big deal?
Driving Your Car With Too Much Clearance
In cases where your valves close too quickly, your engine will lose compression and begin to perform poorly. This is called clearance. Too much clearance causes a rattling sound and lackluster acceleration. Driving with too much clearance leads to less overall damage than driving with tight clearance. But, it should still be taken care of quickly and before your car's performance suffers.

Driving Your Car With Valves Too Tight
The other potential problem is for your valves to close too slowly, which reduces the compression in the cylinder. Driving with the valves too tight causes more damage. In severe cases, your engine may overheat and burn out a valve, which is a much more costly repair. If you notice these warning signs and don't take care of them you will almost certainly regret it. Stick to your maintenance schedule and have your valves adjusted as needed.
 
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