Im runnin an open ypipe....well, a gutted cat and nothin after it. I saw in another post somewhere that this will eventually rust the bottom of my car....its gonna be awile till i can get another exhaust sustem on it. Is this something i should worry about? Can i possibly clean underneath it when i wash it? I just wanna know if i should make my exhaust a top priority or if it can wait awile.

 

I;ve never heard anything about that. It could possibly if you have under coating or paint catch on fire. Thats a maybe though im not sure on that.

 

Moisture and salt are what causes corrosion. I'd be more worried about exhaust stains under your car.

Cleaning underneath your car on a regular basis might help, but an undercoating would be even better.


Ft. Polk huh, sorry about your luck.

 

I believe the exhaust can cause some rust because there are acid fumes in the exhaust- Hydrochloric acid, Sulfuric acid, and Nitric acid. These can corrode the body whether they are present as vapor or if the hot gases condense on the cool body. Salt isn't the only thing that promotes rust.

 

I don't think it really causes rust just really leaves some nice black patches under the car.

 

True, the black patches would be corrosion from the sulfuric and nitric acids which is not rust. The compounds formed by the corrosion would probably help salt produce rust when the surfaces got wet.

 

well so far i dont have any black patches under my car...ive been runnin like this for about 2 months now. Oh and Puka....Fort Polk does suck...im glad im not in the army....there gettin screwed more and more these days....but im just here with my mom and s dad for college...then im outta here...lol

 

Lucky for me I'm in So Cal where there is mostly sunshine and never salt on the roads Still it also depends on where the pipes are facing. If it is directly towards the road then there is a good chance that the acids from exhaust would take a long time to accumulate on the underbody. Even with the black patches its not going to start rust. The black patches are formed by the carbon coming out of the exhaust. The carbon with the acids cake onto the surface of the underbody. With the underbody coating there the carbon and acids just form a surface over the underbody. You can clean off the exaust residue from the underbody but if it's really caked on it's a PITA. It will not cause rust though. As with salt it is going to cause rust anywhere on the car. Salt+metal=trouble. So to answer the original question no it will not cause rust.

 

? Think...if it doesnt cause rust why does your exhaust rot out??

If you ever look at old cars that havent been restored. Many used to have exhaust pipes that exited through the bumper. Those bumpers are now hard to come by. The bumpers totally rot through around the exhaust tips.

 

I'm glad you brought this up. I was thinking about that too. I recently replaced my exhaust because the pipes had rusted through in several places. I know no salt ever got deep into the exhaust. Taking short trips would cause water and acids to condense in the cool exhaust, and if it never got hot enough to evaporate them that acid solution would sit at least till I drove the car the next time. Having an undercoating would help by keeping the acids off the bare metal.

Just an additional note here, you don't want the exhaust to exit onto the tires either. You might think the hot exhaust would help melt snow buildup, and it might, but the reactive gases in the exhaust would age the rubber prematurely. One of the first things I learned on the job when I got out of college.

 

With exhaust systems the heat forms condensation. Over time such as the case of classic cars that condensation rusts the piping, muffler, and any metal around the exit of the exhaust. Ever see water coming out of the tail pipe of a car? But the gases in the exhaust do not rust the metal. They may corrode the metal over time but do not cause rust. Rust is a chemical reaction between iron and water. As I stated before it will just form some nice black patches under the car.