Finding an exhaust leak

[dmksails]

I've a 3GM30F that was recently worked on where the heat exchanger, exhaust elbow, head and injector pumps were all removed then reinstalled.

Now it seems that I'm getting a bad smell in the engine compartment that smells of exhaust and I'm wondering if it's coming from a leak at the elbow.

First question - How do I determine if there is an exhaust leak at the elbow?

[chris mac]

I have the same engines, but am far from being an expert. I had a leak at the elbow and it leaked small amounts of water, which made it easy to find.
Otherwise, I would look over every connection point, making sure hose clamps are tight. Also look for any stains near connection points.
After that watch it running in neutral with the rpm up.
Is there smoke anywhere, or is it just smell? New parts and hoses may off gas the first couple times.

[Kelkara]

I'll echo Chris' comment that new parts can smell ... I recently put on some new exhaust insulation and it definitely smelled a bit "exhausty" for the first couple of hours ... the supplier did warn me, so I just left it running for a few hours without me in the boat, and sure enough the smell was gone the next time.


However if that's not the cause ... I hope you can track it down asap.

[ItDepends]

From before the water injection point exhaust leaks of any significance are usually pretty easy to track down: They are easily heard. The old trick of sticking a meter long piece of 1/4" tubing in your ear, and running the end around will find a leak in no time, if it is there.

There are not a lot of places around the exhaust manifold gas can leak out, and it usually only happens if bolts are loose, or gaskets were forgotten, or messed up somehow.

After the water injection point they are just as easy to find: They leak water as well as exhaust. Look for trails of salt crystals.