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2005 Forester Automatic
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495 Posts
Discussion Starter #1
After driving in heavy slush, my exhaust sounds "boomy" and I smell more unburned gas

Like the title says. A day before driving in the worst slush/ice/snow I've seen in KC, I also rear ended another vehicle pretty hard, kinking the front bumper, but not damaging the coolers or frame. I might have strained some connections.....

I did NOT notice the exhaust sound till the next day after the horrendous snow conditions. The lower shroud (diaper) was knocked loose in the accident and could have admitted more snow/ice into areas around the Y pipe and front cat.

I do not have any loss of power (engine sound like I have an aftermarket exhaust, kid of mean actually), and I have no codes yet. Fuel consumption seems appropriate for this time of year.

-- So long as I do not see check engine lights, is it OK to assume that my leak is BEHIND the oxygen sensors (they are relatively new, Denso, but saw some burned coolant during the last blown HG, threw codes then, but reverted to normal no code status quickly after HD repair). I have read that persistent exhaust leaks may eventually cause rich or lean conditions which could damage an engine. But will those conditions result in a CEL before any damage is done?????????

I was pleasantly surprised at the cost of exhaust components off Rock Auto. Walker cat (not a cali unit) for around $325. Kit for all the rest also around $330. Judging the rust on the bolts and flanges, I would guess that if I try to replace one component, it will be like a domino effect and all parts will be due......

-- My heat shields rattle and have had the hose clamp fixes done in multiple locations. WALKER SAYS THEY INCLUDE REPLACEMENT SHIELDS, THOUGH THE PICS ARE UNLCEAR. ANYONE KNOW MORE????

Thanks in advance....
 

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2005 Forester Automatic
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495 Posts
Discussion Starter #2
Hmmm.. Not many takers...

I'll repeat the question, simply started:

Does anyone know if an exhaust leak can cause damage to an engine, even if no CEL codes are showing?
 

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2018 2.0 FXT-Touring CVT
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2,912 Posts
Hmmm.. Not many takers...

I'll repeat the question, simply started:

Does anyone know if an exhaust leak can cause damage to an engine, even if no CEL codes are showing?
I suppose it depends on where the leak is. If it is after the catalytic converter and sensor location, then I don't think so. If it is before the sensor, it should trigger a CEL. If it is somewhere near the engine? It might, but again, a CEL light would be triggered, or so I would imagine. These cars are highly over-engineered and every little thing that's off can trigger a CEL.
 

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2004 XT 5 MT
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1,093 Posts
First up is to check the fuel lines under the intake manifold, they are rubber and will leak if they are original. They tend to leak in cold weather. Other option is to hook the car up to snap on or the like computer and look at what your short and long term fuel trims are doing to see if the car is indeed running as rich as you are describing.
 

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2010 FXT slush-box
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661 Posts
exhaust leak

After the cats leak should not matter much. People change the back pressure with cat back exhaust all the time without engine damage. Maybe this is your excuse to put something aftermarket on ;)

Jeff
 

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2005 Forester Automatic
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495 Posts
Discussion Starter #6
OK. thanks for all the replies. I will just drive for a month or so, till the weather is better and I can afford to have her down if necessary. I do have an OBDII reader, though I am no pro with things like fuel trim. I'lll try.

I need to get her back up on stands and actually run the engine and really find out where the leak it. It ought to be clear enough from under the vehicle. But I'd rather do that with the garage door wide open and a nice springy breeze clearing out the CO while I'm at it!!!!

Hopefully, if no CEL are firing, I'll not be doing any damage......
 
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