Boat engine cooling system test

[Donald]

I feel I need to pressure test the closed cooling system in my Volvo Penta engine. But assume it could be a special thread Volvo Penta cap. Who knows.

Was thinking I would buy on Amazon the cooling system test kit with most adapters. Hope for the best and return it if none fit.

I emailed Lisle and Mityvac.

 

[AZjeff]

You surely are a boat guy. Do you think you'll get it on the water this year?

 

[Donald]

You surely are a boat guy. Do you think you'll get it on the water this year?

Technically it was in the water several times this year. But did not leave the dock.

 

[Donald]

I asked my Volvo Penta dealer about getting me the proper adapter cap for the cooling system expansion tank and they said they could not get it.

I ordered a cooling system test kit off Amazon with a bunch of adapter caps and some kind of universal adapter. Hopefully one will fit. Free returns.

 

[Donald]

How long should a cooling system hold pressure when running a test? 10 min or 30 min or 60? More?

What pressure? If the cap is the normal 15 lbs then maybe test at 12? Or go with 15?

 

[PontiacHO]

Can you crank it on muffs out of the water? I’d say if it will idle for 30 minutes and keep the system (hoses) pressurized for 30 minutes after shut down you’ve tested as good as it can be. Are you losing coolant or just concerned about the cooling system integrity?

 

[Donald]

Can you crank it on muffs out of the water? I’d say if it will idle for 30 minutes and keep the system (hoses) pressurized for 30 minutes after shut down you’ve tested as good as it can be. Are you losing coolant or just concerned about the cooling system integrity?

I don't have an exacting answer. I bought the boat in Sept 2020 after a sea trial. Obviously it had enough coolant for the boat to run without overheating Boat was not even started in 2021 waiting for Volvo Penta parts from Sweden. This year waited for some additional repair. With that complete the engine was run in idle for about 10 minutes and it overheated just the exhaust manifolds (closed cooling). Engine did not overheat. Noticed the expansion tank was almost empty so I added coolant but to my surprise it took 2.5gallons, with a lot of it flowing into the the engine and exhaust manifolds. What happened to the coolant since the sea trial? So I wanted to do a pressure test to determine if the the system had a leak. The likely component would be the heat exchanger. I probably have air in the cooling system and so I might drain and vacuum fill but if there is a leak in the system I could pull in sea water into the closed cooling system if I pulled a vacuum on the cooling system from the heat exchanger.

 

[mk378]

If there's a significant leak you'll see the liquid level going down as well as the pressure dropping.

 

[Donald]

I was able to successfully test the cooling system and it had no leaks. I coated the adapter cap gasket with a mix of Dawn & water to lubricate it. Tightened the cap with the "key" provided in the cooling system pressure test kit. Instead of the hand pump I used a hose and gauge setup I bought that uses shop air to pressurize the cooling system. I added a tire valve x 1/4" NPT adapter so I could use my cordless tire inflator for the air. The hose and gauge setup has a ball valve to shut off the air supply once at the desired pressure so no possible leak through the air supply.

System held 15 PSI for 20 min with no measure able loss.