If when you take the engine heat exchanger off the engine for cleaning
you notice that the copper tubes that are used to attach the hoses - are eaten away a little, then you need to "pressure test" the heat exchanger.
- - U.S. made heat exchangers are either copper or cupro-nickel (the higher priced ones) and are made by soldering different size copper tubing together. There are short tubes soldered onto the body of the heat exchanger and are used to attach the various inlet and outlet hoses. When you remove the inlet and outlet hoses you may notice that some of the copper metal has been "eaten" away by electrolysis
. If this is the case then you should "pressure test" the heat exchanger as it might just be that the interior
tubes are also been eaten away to tissue thin condition. Rupture of the little tubes will allow raw sea water to mix with the clean fresh water coolant
in your engine. If that happens the salt water
will start to eat away at the inside of the cylinder head
water galleries and other places. A potentially very expensive situation.
- - Of course, you can take the heat exchanger to a shop and pay somebody to test it for a lot of money
- or - you can do it yourself with a garden hose and a second piece of garden hose that you fit with a spray nozzle or shut off valve.
- - Using pipe clamps attach the garden hose (house supply) to one of the raw water inlets on the heat exchanger. Attach the short piece of garden hose with the spray nozzle to the other raw water outlet fitting on the heat exchanger.
- - Turn on the household spigot to the garden hose (nominally 30 to 60 psi) and slowly close the spray nozzle. This will pressurize the heat exchanger raw water side. If there are any leaks
inside the heat exchanger, water will run out of the inlet/outlets of the engine fresh water coolant
side of the heat exchanger. If that happens - buy a new heat exchanger.