Yanmar 3gm30f Ccolant drain

[carlager]

I am planning to change the coolant on our Yanmar 3gm30f.

Do I drain using the screw close to the secondary fuel filter or the screw on the other side close to the oil filter ? Or do I drain from a third place ?

 

[Bill Roosa]

Probably both. If it looks like a on-off drain valve then it has to be coolant. Fuel and oil (the only other fluids) either don't have drains or have plugs on the oil pan. Crack it and test the output. I know my 4 cylinder has 3 drains

 

[kloudie1]

Should be a drain cock under the heat exchanger/exhaust manifold and another on the block on port side aft of the oil filter. The one that is at/close to the exhaust ell is a seawater drain cock.

 

[Claude L.-Auger]

Should be a drain cock under the heat exchanger/exhaust manifold and another on the block on port side aft of the oil filter. The one that is at/close to the exhaust ell is a seawater drain cock.

Here is diagram. The drains with dark arrows are the ones for coolant as described by Kloudie, the other one being the seawater drain.

 

[Menestheus]

easiest is to take hose off water heater plus it is usually the lowest point.

 

[carlager]

Here is diagram. The drains with dark arrows are the ones for coolant as described by Kloudie, the other one being the seawater drain.

Claude,

Thanx. Could you try attaching the diagram again?

 

[carlager]

Thanx

 

[carlager]

Claude, Thanx. Could you try attaching the diagram again?

Sorry. I found it

 

[carlager]

Spoke to a Yanmar dealer today. He told me there is no point in changing the coolant. "You will probably ned to change it on a car maybe every 5th year, but probably never on the engine on your sailing boat." Any views on this ?

 

[py26129]

Spoke to a Yanmar dealer today. He told me there is no point in changing the coolant. "You will probably ned to change it on a car maybe every 5th year, but probably never on the engine on your sailing boat." Any views on this ?

I will change mine this year. The engine is a 3GMF (22HP 3cyl).

My reasoning is that the boat is a 1985 and I do not know the last time it has been changed. Given the relatively small cost of this maintenance item, it only makes sense to refresh the coolant and know that it is good. BTW, the coolant also provides corrosion protection. That alone is probably worth the effort.

That's my thinking. Your thinking may vary

Cheers

Matt