Oh No - another thread about getting the antifreeze in!

[richardabeattie]

So many debates in the past but here I go again. (Raw water cooled 2GM20). With the boat ashore the standard methods seem to be either:
Run the engine on fresh water to flush out (some of) the salt and long enough to open the thermostat - at least 10 minutes - and then run in the antifreeze.
Or alternatively remove the thermostat, replace its cover and clamp off the bypass hose before running in the fresh water and then the antifreeze - a much shorter run time as the engine does not have to warm up.

But what's wrong with simply disconnecting the bottom end of the hose leading up from the impeller to drain the block, reconnecting it and then pouring the antifreeze mix straight into the top of the thermostat housing?

 

[Spyro]

The inlet isn't high enough to drain all the water. There should be a drain point on your 2gm20 just above the engine dipstick. It's a small black plastic knurled knob. You could drain that then introduce antifreeze as you say through the thermostat housing

 

[[2574]]

I pour it directly in to the raw water cooling basket/sieve.

 

[richardabeattie]

Robih - that would mean running the engine. Pouring it into the thermostat housing having previously drained out the water avoids that.

 

[Spyro]

I pour it directly in to the raw water cooling basket/sieve.

On a 2GM20 the engine has to be up to temp and the thermostat open otherwise the water bypasses the block as the closed thermostat shuts off the path through the block.

 

[richardabeattie]

Spiro

Yes but I knew that! The question is whether to remove the thermostat to enable the a/freeze to go through the engine even when it's not warm. But having looked at the 2GM20 again I can see that clamping the bypass hose is impractical - it's very short and clamping it would damage it. So I'm still looking at the option of draining out all the water and then pouring the a/freeze into the top of the thermostat housing (with the thermostat removed). Sounds far simpler than running the engine when the boat's ashore.

 

[RichardS]

If you remove the thermostat and fill the system cold through the heat exchanger then the antifreeze mix should fill the whole system. I suppose that the only part that might not fill is if there is an airlock somewhere at the top of the cylinder jacket which would normally be driven through by the circulation pump?

Perhaps there is a hose clamp at the highest point or even the thermostat housing itself, which you could crack open until antifreeze starts to come out?

Richard

 

[VicS]

If you remove the thermostat and fill the system cold through the heat exchanger then the antifreeze mix should fill the whole system. I suppose that the only part that might not fill is if there is an airlock somewhere at the top of the cylinder jacket which would normally be driven through by the circulation pump?

Perhaps there is a hose clamp at the highest point or even the thermostat housing itself, which you could crack open until antifreeze starts to come out?

Richard

I dont think the OP can do that. ................ A raw water cooled 2GM20 does not have a heat exchanger

However, I expect your advice will be useful to anyone with a 2GM20F

 

[richardabeattie]

But my new found diesel engineering mate says "Who needs antifreeze - just drain out the sea water from the engine and the water trap and have a happy Christmas".
I wish I had taken up stamp collecting.

 

[vyv_cox]

But my new found diesel engineering mate says "Who needs antifreeze - just drain out the sea water from the engine and the water trap and have a happy Christmas".
I wish I had taken up stamp collecting.

Exactly what I have always done. I didn't own my boat from new but I believe its Bukh engine received no special treatment whatsoever. In the days before all this knowledge was available in forums I never did anything special to it either, although I do remember flushing it in fresh water a couple of times but never added antifreeze. At that time I was unaware of the need to get the thermostat open during flushing, so there is a very good chance that the engine remained salty, but drained. When I replaced it it was 20 years old with no sign that this wintering procedure had done it any harm at all.

 

[RichardS]

I dont think the OP can do that. ................ A raw water cooled 2GM20 does not have a heat exchanger

However, I expect your advice will be useful to anyone with a 2GM20F

Ah .... I should have gone back to the start of the thread rather than just reading the OP's post #6.

Still, as you say, it might help freshwater-cooled engine owners who don't want to run the engine.

Richard

 

[James_Calvert]

Running the engine ashore can be very straightforward. Just need a supply of water.

I do it from outside with a bucket put near the seawater inlet, a tube from the bucket jammed snugly into the inlet and a hose running into the bucket to keep it topped up.

No engine dismantling. All you need to find is the right diameter tube.

 

[richardabeattie]

James - you are missing my point. What you describe is of course what is often recommended but only works if the engine is run long enough ho open the thermostat. That can be quite a long time.

 

[James_Calvert]

Fair enough. It only takes a few minutes for my engine. Several bucketfuls, hence the use of the hose. I can tell when the thermostat opens (and closes) because the exhaust water runs hot (and cold).

I've also done something similar inside the boat by rerouting and extending the inlet pipe to pick up water in the galley sink, keeping it topped up by running the tap, supplemented by a couple of buckets in reserve. Much more bother, and only did it that way because I wasn't getting the chance to run it ashore.