Yanmar Coolant Change

[Ilanortho]

Hi;
I need to replace the engine hoses on my 3GM30F. What is the best way to drain the antifreeze in a tight engine compartment without making a mess?
Thanks.
Ilan

 

[whatfiero]

There are 2 drain plugs or drain cocks originally they had clear tubing commuting off them there on right side engine one at bottom heat exchanger and 1 bottom block if coolant old or chunky it's hard to get all coolant out those small drains compressed air helps push coolant out . If ya just changing coolant I remove hose running to hot water heater and add a New hose from engine to 5 gal bucket and run engine on water hose till clear water starts to fill bucket. Takes several buckets then drain and fill with 50/50 antifreeze my pressure cap hard to get to so I turn up the short piece heater hose and pour in with transmission funnel

 

[splax]

I would first try to drain using the clear drain tube into a bucket. If I wanted to flush the system I would detach the hose going the hot water heater at the heat exchanger, attach a hose from the heat exchanger to a bucket, then attach a fresh water hose to the water heater hose, then have fresh water push the system fluid out to the bucket. After clear discharge is achieved, detach a hose at the water heater and allow to drain to bilge.

 

[Gunni]

Just did this job in the fall. I bought about 10 feet of the proper PVC tubing and connected it to the engine coolant petcocks, draining each into a bucket placed down gradient in the cabin. That will drain your engine hoses.

 

[Ilanortho]

Thanks for all the suggestions. My engine space is tight and bucket would be in cabin. If using the water heater hoses, how do you get it out there?
The PVC tubing - where did you purchase it?
Thanks
Ilan

 

[Gunni]

PVC hose of all sizes are typically found in the plumbing section of home supply and hardware stores.

For the water heater loop, take one hose loose at the engine and using an air pump (inflatable boat) , pressurize the heater loop after you have drained the engine block via the petcocks. The coolant will be pushed into the block and out the petcocks drains. You can also do this orally, but be aware that AF is toxic is very small doses...so have your brother in law do it.

 

[Ilanortho]

My sister divorced him which is actually a shame! Really liked him.

Thanks for the instructions; really appreciate it!

Ilan