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Yanmar coolant replacement

24K views 8 replies 7 participants last post by  lsbrodsky 
#1 ·
Getting ready to replace the coolant in my Yanmar 3HM series engine. Researching different products and looking at the Shell Rotella ELC diesel ready brand. Looks like it's premixed with 50/50 ratio and claims extended life. Does anyone have experience using this product or make any recomendations?

Thanks,

John Schwab
PSC 34 # 201
Norstar
 
#3 · (Edited)
"Extended life" coolant (ELC) is red in color. It doesn't mix well with green antifreeze.
There is no reason to put more expensive "extended life" coolant into system, IMHO...
Green (normal life) antifreeze needs to be removed completely from the system...

"Extended life" antifreeze was designed for latest generation of on-highway diesel trucks. They have engine's systems running extremely hot due to latest EPA regulations. The coolant was designed to withstand higher temperatures and corresponding wear of cooling system.

Boat's engines don't work that hard, besides most marinas don't have red antifreeze in stock, so topping off the cooling system can be a problem, if you don't have enough coolant on board.
 
#6 ·
I just completed a marine diesel engine course. They made a point of cautioning (as stated above also) . . . be sure you completely empty and flush the old green stuff before changing over to one of the new red extended life types. It was recommended to go with pre-mixed so you don't have to keep distilled water on hand for future top-offs. Never use tap water. The instructors recommended changing the anti-freeze every 3 years, regardless of other factors.
 
#7 ·
I've wanted to change the coolant for years as mine is about fifteen years old. But none of my books really show how. Can somebody recommend some steps? How do you pump out old coolant? How do you dispose as this is not enviro-friendly stuff. How do you "flush" the system?
 
#8 ·
In the class, the instructor recommended that you let a professional do the flush and refill so you get a good pressurized flush out (particularly if its been many years since you've changed your coolant) and so there's no chance of an air void remaining in the cooling system. The Yanmars are a little less prone to this then other engines (those with bolt on heat exchangers), but it can happen (e.g., in the lines / plumbing for the hot water heater). You may want to consider letting a pro do it the first time, if you're unsure of what you're doing.

While you're at it, if your engine's getting a little older and it's never been done before, consider if you want to replace the pressure cap(s) and maybe even the thermostat. If you have a higher remote tank with a cap (due to a hot water heater installation) and a pressure cap on your heat exchanger, be sure the pressure cap on the (lower) heat exchanger is rated for higher pressure than the cap on the (higher) remote tank, which should be as specified for the engine.

The heat exchanger and oil cooler (if you have one) should be serviced at least every 1000 hours as well (raw water tubes are prone to clogging with impeller blades, bio garbage, etc.), and of course monitor your exhaust output routinely to make sure there's no raw water restriction due to carbon build-up in the exhaust elbow.

Goes without saying, check the specific gravity of your coolant as part of our winterization routine (or once a year) using a meter appropriate for the coolant you're using.
 
#9 ·
John,

When I had Deaton's do a flush they replaced it with the Rotella. The Rotella supposedly lasts a long, long time. Prior to that, I replaced the green every year. The only problem with the Rotella was finding it. I finally found a bottle for make-up at a local truck place. You cannot mix the Rotella with anything else. Then I had the engine overhauled and just went with standard DEX coolant. I decided replacing it every 2-3 years would be my new plan.
Larry
 
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