I think I have an Exhaust Leak?????

[Brian McVickers]

So I think I have an exhaust leak but I can't find it.
Anyone know of an effective way to fine a possible exhaust leak???
This is on my 2001 Land Rover Discovery II.

Upon initial start up I hear a rough "blap lap lap" sound coming from the passenger side of the engine.
There is no smoke and performance seems normal but this sound is telling me there is a leak somewhere. Also note that the sound is loudest upon initial cold start up and then diminishes as everything warms up. However It will then get more pronounced, louder, with acceleration.

With the engine cold I have crawled under the vehicle and examined and felt every inch of the exhaust system I could reach. I have found no holes and no cracks by sight or touch. With the engine on I can hear it but can't see it. There are no signs of exhaust smoke coming from anywhere -- Maybe I should try this on a very cold morning?

I did see that at some point I had hit or touched a rock with the exhaust piping coming from the passenger side header just before it gets to the catalytic converter. ??-Is there a chance that by hitting this portion of the pipe on a rock that I could have unseated the gasket where the header connects? Would this cause a blap blap sound? The contact did not dent the pipe but it made a visible scrape and it is obvious that there was contact.

So short of taking it into an exhaust shop or the dealer I am wondering if there is a good method for locating the origin of the sound. Is there a safe additive of some sort that will maybe smoke and show the path of the exhaust gasses and any leaks?

Thanks
Brian

 

[Scenic WonderRunner]

<<<QUOTE: I did see that at some point I had hit or touched a rock with the exhaust piping coming from the passenger side header just before it gets to the catalytic converter. ??-Is there a chance that by hitting this portion of the pipe on a rock that I could have unseated the gasket where the header connects? Would this cause a blap blap sound? The contact did not dent the pipe but it made a visible scrape and it is obvious that there was contact.>>>

Brian.........

I was going to say check the bolts and gasket on the noisy side of your head.....then you stated it.

I just had Headers put on my 4Runner after my complete engine rebuild. I was hearing Extra noise from the engine (so, like you, I was crawling all around trying to find the leaks).....especially when driving next to a building or hillside that would bounce the sound back to my window. I had to take my truck back for some warranty work already...told them about it....and luckily they seemed to have fixed it.

Check your bolts and gasket.....like you mentioned..........if that's not it, you may have to take it to an exhaust shop. My local guy here in my town only charges $50 bucks an hour.

I think the only other place you could have a leak is at a "weld bead".....so check all of those. I did......and that's where I found a few leaks. When they installed my headers.....they has to create a new crossover.....which added more weld beads.

Good luck!

 

[Pskhaat]

You can do a SeaFoam treatment, when you start it back up and it smokes, you'll definetely be able to tell from where it's leaking...

 

[Brian McVickers]

Thanks for the feedback and ideas!

I checked all the bolts on the headers and any other bolts on the system that I could access. None of them were loose and actually they would not budge to tighten so I did not force at all.

About the Sea Foam, does anyone understand how it works or what it does?
I didn't really get it from reading the website, sounded a bit like snake oil!

 

[Scenic WonderRunner]

Hasn't snake oil been working since the 1850's..........!!>? .....hehe

 

[Pskhaat]

Yep, a little bit like snake oil. I do believe it does do the job of removing some carbon. If you've never SeaFoam'd your vehicle, the smoke it generates is unbelievable. I can't say it improves anything, but does cause some old stuff to be burned and thus generate enough smoke for you to find exhaust leaks.