Coolant change/flush Yanmar 2GM20F

[Blue Drifter]

Grateful for advice on this, relatively happy with draining old coolant from the 3 x taps/spigots on the port side of engine, but unsure of what exactly is involved in the 'flush' bit. A few pointers would be appreciated.

TIA

 

[RichardS]

Grateful for advice on this, relatively happy with draining old coolant from the 3 x taps/spigots on the port side of engine, but unsure of what exactly is involved in the 'flush' bit. A few pointers would be appreciated.

TIA

There are many previous threads on this. Have you tried a forum search?

Richard

 

[VicS]

Grateful for advice on this, relatively happy with draining old coolant from the 3 x taps/spigots on the port side of engine, but unsure of what exactly is involved in the 'flush' bit. A few pointers would be appreciated.

TIA

Pretty much the same procedures that you would use to change coolant and flush the system as you do with your car

If you only want to do a simple single flush refill with water, run the engine up to temperature , allow to cool and drain.

If you are flushing to change from a conventional or unknown antifreeze to one of the recommended long life antifreezes repeat the flush a total of three times or until all signs of the old antifreeze have gone ( I understand there are some specific recommendations on antifreeze)

If you are flushing to more thoroughly clean the cooling circuit use a radiator flushing solution following the maker's instructions.

When refilling add the appropriate quantity of antifreeze then fill up with water. If your tap water is hard or high in total dissolved solids use distilled or deionised water or , if it is available, buy the antifreeze ready diluted.

Remember ethylene glycol is sweet tasting therefore pleasant to drink but toxic to mammals including pets and children Therefore dispose of old antifreeze responsibly and safely.

 

[Blue Drifter]

Thanks Vic, very useful and just what I was after. Now that you have logically categorised the various options, I can see I need to carry out the changing from unknown antifreeze procedure. The disposal warning is also a good and valid prompt. Once again thanks.

 

[vyv_cox]

If the old coolant comes out looking rusty it is probably worth using a radiator cleaning product from your local car accessories shop. I used some on my old BMC diesel and was astonished to see how much rust it removed. I then flushed with water a couple of times before filling with new coolant. OTOH when I changed the coolant on my 3GM30F a couple of weeks ago it came out perfectly blue, so I did nothing except replace it with fresh coolant.

 

[VicS]

when I changed the coolant on my 3GM30F a couple of weeks ago it came out perfectly blue, so I did nothing except replace it with fresh coolant.

So you are not using one of the long life antifreezes Yanmar recommend

,

 

[vyv_cox]

So you are not using one of the long life antifreezes Yanmar recommend

,

My engine has had blue antifreeze in it since it was first installed. My workshop manual for the 3GM30F states that ethylene glycol based antifreeze should be used.

 

[VicS]

My engine has had blue antifreeze in it since it was first installed. My workshop manual for the 3GM30F states that ethylene glycol based antifreeze should be used.

They are virtually all ethylene glycol based . Only the non toxic ones are propylene glycol. Not common as engine antifreeze in UK . The different types of ethylene glycol antifreeze are the conventional low silicate type (usually blue or green), the long life or "organic acid technology" (OAT) type (usually red, pink, orange or yellow) and a hybrid type

The Yanmar manuals I looked at as a result of this thread were suggesting one of a select few extended life antifreezes. I believe the recommended ones have additives to combat cavitation erosion of wet cylinder liners which I thought might be a topic more up your street than mine.

 

[vyv_cox]

They are virtually all ethylene glycol based . Only the non toxic ones are propylene glycol. Not common as engine antifreeze in UK . The different types of ethylene glycol antifreeze are the conventional low silicate type (usually blue or green), the long life or "organic acid technology" (OAT) type (usually red, pink, orange or yellow) and a hybrid type

The Yanmar manuals I looked at as a result of this thread were suggesting one of a select few extended life antifreezes. I believe the recommended ones have additives to combat cavitation erosion of wet cylinder liners which I thought might be a topic more up your street than mine.

I cannot claim to have kept up with any changes that Yanmar have made, the antifreeze I have used for years is as specified in the operator's manual and workshop manual. Unlikely that any fancy stuff would be available in Greece anyway.

I have worked a little in the area of cavitation control by antifreeze additives but would have thought that the small 1, 2 and 3 cylinder engines were too small for this to be a problem. The photo shows an example from perhaps 50 years ago but I have seen almost identical damage far more recently. That was in Oman, where the operators did not see the need to add antifreeze, ignorant of the beneficial effects that it has in both corrosion and cavitation control.