Exhaust leak!

**uLs1a** · 03-04-2009, 11:22 AM

Well over the weekend I have to take my heads off to swap out lifters and pushrods. While I was unbolting the cats from the stock manifolds I snapped one of the three rods on both exhaust manifolds, they had 3 but now only have two on each side. I got the car back together and bolted the cats back to the exhaust manifolds, now I have a pretty bad exhaust leak where the manifolds bolt to the cats. I know I can not pass smog with this leak but will this leak cause damage to my cas since the leak is right where they start?

**Wesman** · 03-04-2009, 11:42 AM

Originally Posted by uLs1a

Well over the weekend I have to take my heads off to swap out lifters and pushrods. While I was unbolting the cats from the stock manifolds I snapped one of the three rods on both exhaust manifolds, they had 3 but now only have two on each side. I got the car back together and bolted the cats back to the exhaust manifolds, now I have a pretty bad exhaust leak where the manifolds bolt to the cats. I know I can not pass smog with this leak but will this leak cause damage to my cas since the leak is right where they start?

Damage?? Not likely in your case.

However, running with an exhaust leak can definitely throw off your short term and long term fuel trims. Meaning the oxygen sensors will be getting inncorrect readings, because pirated air is entering the exhaust stream right near the sensors. This can make the car run improperly. You would end up with a rich condition, because the O2's would be sensing extra oxygen in the exhaust (which normally indicates a lean condition) and the PCM would try to correct the condition by adding extra fuel.

Just get it fixed as soon as its convienent for you.

**uLs1a** · 03-04-2009, 11:44 AM

I know my A/f would be off, but I also had some guy on LS1tech tell me my cats will get damaged

**Wesman** · 03-04-2009, 12:02 PM

Originally Posted by uLs1a

I know my A/f would be off, but I also had some guy on LS1tech tell me my cats will get damaged

Not likely.

Cats need oxygen to work, what damages a cat is when it gets loaded up with HC that it can't oxidize. So extra oxygen entering the cat shouldn't hurt anything. Thats basically what your AIR system does, it adds oxygen to the cats on startup to help them light off quickly.

**JaycenK** · 03-04-2009, 08:49 PM

I'd be more worried about burning something were they leak. I have never had an LS car so I have no idea were your cats are located but on my 97 I would be burning up my oil pan.