switching from pink coolant to yanmar red,how to flush syste

[jimbeam]

I want to flush my coolant system from pink coolant to yanmar red. How do you flush entire system on yanmar 4jh4 hte?
I'm new at this so need detailed instructions.
Jim

 

[BB marine]

I just did a flush and and Anti-freeze change on the D3 Volvo. Its not the same engine but procedure should be the same.

Find Low point drain, The easiest one to get to Block drain is located by the oil filter or the exchanger drain. I drain the easiest to get to and capture the antifreeze.

Remove the fill cap and open the low point drain catch as much antifreeze as possible.

Close the valves for hot water and bus heater coming from the engine. Remove the Bus heater and hot water hose from the engine both upstream and downstream. Between engine and Valve. ( mark hoses for proper location) Valves stay with hoses going to hot water heater. Valves stay closed. Capture any antifreeze that leaked while removing the hoses from engine.

Once the low point drain from engine has quit dripping, remove the other drain plug ( exchanger ) capture antifreeze.

Block is now drained, close drain plugs

Pour a gallon jug of distilled water into the engine coolant fill.

Next, I use a small drill pump for this step. Fill the gallon jug with water (Tap Water) Drill pump has a hose on each side 5/8 id hose. Attach one drill pump hose to one of the hot water heater valves place the other hose into the jug. Place the second valve into a bucket. Open valves, drill on ,suck the gallon jug of water out and pump thru heater and bus heater until clear water is going into the bucket. close valves.

Dispose the anti freeze in the bucket.

Place the drill pump hose still attached to the valve into a gallon jug of anti freeze place the other valve into the empty bucket, open valves , pump on, pump the anti freeze until straight antifreeze is going into the bucket. Close valves. The water heater and bus heater are flushed and bleed with antifreeze. Keep valves closed.

Drain the water from the block and exchanger. This should have mixed with any antifreeze that was left in the block and diluted it to remove existing old antifreeze.

Install drain plugs tighten securely. Install hot water heater and bus heater valves back to proper location to engine hoses. Keep valves closed.

Pour new antifreeze in fill until full. Leave cap off, it will burp a few times, refill to full level. Start the engine and let it warm up and circulate the anti freeze this will remove air pockets in the block.

Let the engine cool down and the recheck level, top off, open the valves for the hot water heater and bus heater. This is bleed and filled so it should not lower the anti freeze level.

Check for leaks, you should be good. I would check the level as normal engine checks.

I have used this method and find it is clean, and environmentally safe and reduces air locks in the system that can lead to low antifreeze levels after a flush and change. Once your set up to do this it takes less than an hour from start to finish and a clean bilge.

 

[knotflying]

My experience with the 4by2 is you can only drain half of the fluid. Not sure if it would be the same with yours. If that is the case I may have a different approach. Drain what you can. Disconnect the heater hoses that run to the water heater and helm heat and blow them out while capturing the antifreeze and dispose of properly. Reconnect the hoses. Then keep adding distilled water until it starts draining clear. Let it drain completely and assuming that half the fluid in the system is now distilled water add straight antifreeze (not the diluted you can buy). This will then mix with the distilled water. Fill to the top with non-diluted antifreeze. Run the engine a bit and let the coolant circulate briefly. At this point I would keep adding antifreeze at a 50/50 mix until all air is dissipated.