Flushing Yanmar 2GM20 Raw cooled - Rydlyme

[thomd]

I am looking at flushing my Yanmar 2GM20 raw water cooled circuit with Rydlyme to clear build up in the channels.

I have seen Rydlyme recommended quite a bit on this forum.

I was wondering how I go about making sure the solution goes through the block rather than the divert pipe at the thermostat when the engine is cold. I was going to use a 12v pump and pump round the solution from a bucket.

Has anyone done this with their Yanmar? Any tips on how I do this and how to force the solution through the block appreciated.

Thanks.

Thom

 

[VicS]

I am looking at flushing my Yanmar 2GM20 raw water cooled circuit with Rydlyme to clear build up in the channels.

I have seen Rydlyme recommended quite a bit on this forum.

I was wondering how I go about making sure the solution goes through the block rather than the divert pipe at the thermostat when the engine is cold. I was going to use a 12v pump and pump round the solution from a bucket.

Has anyone done this with their Yanmar? Any tips on how I do this and how to force the solution through the block appreciated.

Thanks.

Thom

Take the thermostat out

Rig up a recirculating system to circulate the cleaning solution, by running the engine, from a bucket or drum through the engine , catching it as it comes out of the exhaust and transferring it back to the bucket. You can use a small pump for this or the wife.

This will not only circulate the solution but also warm it. Wife will also enjoy being part of the proceedings

 

[vyv_cox]

You will find it far more effective using Vic's method than doing it cold. Reaction speed doubles for every 10 degree increase in temperature. When I have used Rydlyme or something similar in my central heating system at home the instructions called for it to be run for a couple of hours to let the chemical do its job. No need for that long in your engine but the heat will help a lot.

Not sure of the need to remove the thermostat. Once the engine is up to temperature the bypass will close and all the flow will go through the engine.

 

[thomd]

Thanks a lot for the suggestions.

 

[VicS]

Not sure of the need to remove the thermostat. Once the engine is up to temperature the bypass will close and all the flow will go through the engine.

I was thinking that without the thermostat it will circulate through both engine and bypass even if it is not at full working temperature.

 

[vyv_cox]

I was thinking that without the thermostat it will circulate through both engine and bypass even if it is not at full working temperature.

Because the thermostat on Bukh and Yanmar raw water cooled engines acts as a diverter valve between engine and bypass, removing the thermostat can have unexpected effects. I have heard of engines that boiled after the thermostat was removed because all the flow preferred to go through the bypass.

 

[snowleopard]

Because the thermostat on Bukh and Yanmar raw water cooled engines acts as a diverter valve between engine and bypass, removing the thermostat can have unexpected effects. I have heard of engines that boiled after the thermostat was removed because all the flow preferred to go through the bypass.

Correct. The function of the diverter relies on the thermostat blocking the bypass when hot.

I'm planning to do something similar so how's this for an idea:

Run the engine up to full operating temperature then take the intake hose and stick it in a bucket of the solution till it's all sucked up then stop the engine and let the block heat up the solution. Once it's stewed for long enough, reconnect to the normal water intake and start it again to flush the solution out.

 

[pagoda]

Correct. The function of the diverter relies on the thermostat blocking the bypass when hot.

I'm planning to do something similar so how's this for an idea:

Run the engine up to full operating temperature then take the intake hose and stick it in a bucket of the solution till it's all sucked up then stop the engine and let the block heat up the solution. Once it's stewed for long enough, reconnect to the normal water intake and start it again to flush the solution out.

I had a look at the thermostat on my 3GM30- and pickled it in warm white vinegar for a couple of hours. There was a surprising amount of CO2 released, so it did help clean it up.
The same vinegar (with a little patio cleaner) solution was circulated round a bucket / hose circuit until it warmed a little. Loads of froth generated, so deposits were removed.
Your suggested method should work just as well I reckon. I also took off the exhaust manifold cooler cover and scraped out some of the rusty gunge. Improved flow all round . Ditto the exhaust elbow. Both are worth looking at if you are bothering to de-scale.

 

[KREW2]

Correct. The function of the diverter relies on the thermostat blocking the bypass when hot.

I'm planning to do something similar so how's this for an idea:

Run the engine up to full operating temperature then take the intake hose and stick it in a bucket of the solution till it's all sucked up then stop the engine and let the block heat up the solution. Once it's stewed for long enough, reconnect to the normal water intake and start it again to flush the solution out.

That's what I do with my Volvo.
Then I remove the thermostat and undo the lowest drain plug at the bottom of the block. It usually needs a good prod with a piece of wire then gungy green water comes out. Once drained I pour fresh water into the engine, via the thermostat housing, until it comes out of the drain hole clear.

 

[Pladdatoo]

Don't forget to remove your internal anodes before the flush. Might not be much of them left afterwards!

 

[pagoda]

Don't forget to remove your internal anodes before the flush. Might not be much of them left afterwards!

Thanks for that - forgot to mention removing them! -3 GMs have three pencil anodes....worth keeping!