Small boat engine servicing - How to drain coolant & how to change a thermostat

[@giog714]

Thanks for the video. What is not clear is how to open the taps, Thanks for explaining

[@confidencesailing]

Hi Giovanni, you just unscrew them from the engine block. I undid them until they were just about open before adding the pipe... In the video you will see me twist the pipe and that turns the already loose tap until the liquid starts coming out. Hope that explains it. And I agree it's not explained that well in the video.

[@i1uvpreppyxo887]

I cannot tell you how many times I have referred to your videos while working on my D1-30F. Thanks

[@confidencesailing]

So glad they have been some use. Thanks for watching

[@NickVass1000]

Very good instructions

[@confidencesailing]

Thank you very much

[@RaulMartinez-ln8zq]

Great video!

[@confidencesailing]

Thanks for watching

[@pierremartin592]

Hello, for which reason you removed the expansion tank from originally mounted engine support bracket, and installed the boat frame ?

[@alskvortsov]

"We should open taps" Where are the taps? How to make the coolant to run actually out of the engine?

[@bryllupsfotofilm]

Hi! My Volvo Penta 5D A 1982 doesn't have a coolant or sea water strainer. The previous owner told me that the cooling system has been modified to a freshwater setup, so I don't need to do anything. I also don't see any container where coolant could be added. Is it true that I don't need to do anything, or do I need to add coolant in some way? How is this monitored? I've also seen some MD 5 engines with a shut-off valve with a red handle on the lower left when looking from the back, but on my engine, it feels like something is there, but the handle is missing. Was it removed for some reason? Perhaps because of the change from saltwater to freshwater cooling? Could someone clarify this for me or provide a link where I can read more about it?

[@bernardhill9160]

Is the d 20 the same location for thermostat

[@johnelliott7443]

Thanks for video I have a D1-20f, first time changing coolant I have drained coolant from drain nipples but only got coolant from top nipple have tried pushing cleaning rod to bottom drain point but with no luck. Any ideas before taking things apart. Engine only 400hrs on clock, will i need to look at heat exchanger next? have also tried to flush out. Many thanks.

[@confidencesailing]

Sounds complicated. That might need someone to have a look.

[@kennethwestergaardjensen93]

How often should the thermostat be changed? I cant find anything in the manual in regards to it 🤷🏼

[@confidencesailing]

I tend to change every two years. With these engines, if you have gone to the trouble of draining the coolant you might as well change them.

[@svDUCHESS]

Is it necessary to drain from both nipples simultaneously, or can I drain one and, when finished, move the hose over to the other one? Thanks.

[@confidencesailing]

Yes you can drain from either chamber separately. Thanks for watching

[@sailson8612]

I want to know what peoples opinions are on flushing out their heat exchangers.. ?

[@giog714]

Hello, I didn’t get what you put in the heat exchanger after washing…what was the name of the product that clean and protect from corrosion? Thanks !!

[@confidencesailing]

Hi Gio G; any antifreeze/corrosion inhibitor/coolant for use in closed engine cooling systems. Usually Ethylene Glycol based.

[@24hourtravellers-]

What happens if we don't flush it?

[@confidencesailing]

Short term probably not a lot. Longer term you will get a build up of gunk that will restrict water flow and cause the engine to overheat at lower revs than normal - meaning you can't run the engine at full power. Plus there is increased risk of corrosion and potential failure of components within the heating circuit. Not replacing the thermostat is increasing the risk it will fail. That will also cause early overheating. None of which is fun if you're out at sea and need your engine to get home.

[@24hourtravellers-]

@@confidencesailing can we flush without running the engine? We are pouring water into the expansion tank n let it flow out thru the nipple. Is that considered flushing? We're doing many rounds of this.

[@confidencesailing]

​ @24 HourTravellers absolutely. flush away to your hearts content with the engine cold. Once you've filled it up again with anti freeze/corrosion inhibitor and sealed the system back up again... Then you can start the engine in idle and the water pump will circulate the new liquid and allow all the bubbles and air locks to eventually make their way to the header tank.

[@24hourtravellers-]

@@confidencesailing ok thanks for the tip 🙏 btw here we don't use anti freeze. We're in Malaysia. 😊

[@JRNAVARCH]

@@confidencesailing should leave the thermostat out when flushing with rad flush?