Exhaust Manifold leak?

[Kevin H. in Atl.]

I have a 99 Cab with PSE.

As we all know, when driving with the top down, and along a wall or fence, you can hear the PSE quite well.

When first driving the car (cold start), the sound seems to include what I can only describe (for a lack of better terms) as an exhaust leak, as if there was a exhaust manifold problem or a muffler can problem. It seems to go away after the engine is fully hot. And I don't notice it when not adjacent to wall or similar surface.

Does this make any sense?

Is it possible for a manifold leak to exist and to be louder when cold than when warm? The manifold itself looks fairly clean. Does this engine have an exhaust manifold gasket that could have failed?

Could this be an issue with the PSE can? (Electronics are not installed).

Anyone have any ideas?

Thanks.

[ToblertheDog]

Kevin,

I have PSE and think I recognize what it is your describing. Generally on a cold startup I get more resonance than when the engine is warmed up. For example, while in neutral & after a cold start, I'll rev the engine (4500-5000RPM)...only to get a much louder sounding exhaust note. This is the only time I get any resemblance to mild/loud resonance. I wouldn't classify this as an exhaust/header leak by any means...assuming you are experiencing the same on your end. When warmed up, everything sounds good.

Anyway, not sure this helps, just another perspective.

[Kevin H. in Atl.]

Thanks for the reply Tobler.

It's not a resonance issue, it's more of a wispy, air movement type of sound, like exhaust is escaping somewhere. It definitely goes away after the engine is hot, as if the expanded metals close the offending gap.

I found there is an exhaust manifold gasket, and a manifold to cat pipe gasket.

I wonder if these begin to leak over time. My car is 7 years old now.