Question about heat shield

[nyorkster]

When I bring the engine to more than 3,000 rpm I hear a noise that sounds almost exactly like a electric wood saw cutting into a piece of wood. The sound seems to be coming from below the car near the front. Could this be caused by a loose heat shield? If is their any easy way to tighten it or do I need to take it in to be welded.

[idosubaru]

they're really annoying and yes it could definitely be a heat shield.

 

often times you can just get a hose clamp, wrap it around the loose section and screw it on tight. *very* common and simple solution. see if this works, it often does. worm two hose clamps together if you need it really long.

 

some people use self tapping sheet metal screws to reattach them, but i do not recommend that for various reasons...like screws ending up in the road if they fall off.

 

you can also just bend them out of the way of whatever they're vibrating against. not likely to help but sometimes that's an easy solution depending what exactly is going on.

 

or you can rip it off. they can be hard to get off though sometimes, but that is my preferred method, they only get worse with time, not better.

 

an exhaust shop may be able to weld it back in place, depending how/where it separated and what's left to work with.

[Rooster2]

they're really annoying and yes it could definitely be a heat shield.

 

often times you can just get a hose clamp, wrap it around the loose section and screw it on tight. *very* common and simple solution. see if this works, it often does. worm two hose clamps together if you need it really long.

 

some people use self tapping sheet metal screws to reattach them, but i do not recommend that for various reasons...like screws ending up in the road if they fall off.

 

you can also just bend them out of the way of whatever they're vibrating against. not likely to help but sometimes that's an easy solution depending what exactly is going on.

 

 

or you can rip it off. they can be hard to get off though sometimes, but that is my preferred method, they only get worse with time, not better.

 

an exhaust shop may be able to weld it back in place, depending how/where it separated and what's left to work with.

 

 

 

The only reason that Subaru installs the heat shields is to prevent a grass fire should you park in tall very dry grass. Which, I am guessing is almost never. Unfortunately over time, the metal heat shields crack, then when loose, it vibrates to make that shrill buzzy sound at certain engine rpm......very annoying.

 

I prefer to drive my car up on ramps, then have someone hold the gas pedal down at the right rpm to make the noise. From underneath, I identify the offending shroud, then with a hammer, I drive a bolt in between the shroud and the pipe as a wedge to stop the shroud from vibrating. It is a low tech solution to a low tech problem. Good luck on your fix!

[GeneralDisorder]

The only reason that Subaru installs the heat shields is to prevent a grass fire should you park in tall very dry grass.

 

That's not true at all - the heat sheilds are there to keep the exhaust heat IN the pipes and to maintain critical exhaust temperature for proper catalytic converter action. Many people have found that their brand new unsheilded "performance" header causes a P0420 catalytic converter effeciency code because they are venting heat to the ambient air through the long unsheilded exhaust runners.

 

Personally I just remove the entire front exhaust header and cat section, find all the loose heat sheilds, and tack weld them to the pipe itself. Then I coat the whole thing in header paint to prevent rust.

 

GD

[efseiler]

I used 'U' clamps to get rid of the rattle in my old OB. Now it makes a metallic 'bonging' sound in my new Subaru (and I think it's 'pretty cool' so I just leave it). :-D

 

 

--Damien

[efseiler]

There's probably a lot of truth to what he says. In my old Subaru they put in some whole new, funky, different exhaust assembly and it really cut into HP, mileage, pickup, etc.

 

 

--Damien