Does anybody have a preferred business to pressure test exhaust manifolds in the DC, MD , Virginia area?

Do it yourself it's not hard, just put are to it and listen .

Hook it up to a garden hose - pressure up - big holes are easy, small holes may take awhile - stand the manifold up and see if water comes out - A small leak ( couple of drops) will not hur the engine, but the fact is a leak will never fix itself so the manifold should be replace or welded -

You will have $ 10.00 in fittings and hoses - be sure to bleed the air out of the system -

My experience. Got some water in the engine so I first pressure tested dry pipes using the garden hose. Must be about 50lbs pressure compared to the 10-20 going thru when the boats running. Didn't find any leaks so I checked the aluminum intake. Some corrosion around the fittings so I replaced it. Put the system back together. After the boat started running like crap I pulled the manifolds again and again had water. Replaced the exhaust, everything is fine. My guess is when pressure testing any holes or cracks were tight and nothing showed up. When the system got hot they opened up.