Simple question about coolant recovery tank

[MJH]

Originally Posted by regex

Hello folks.

Ok, I searched and I didn't find my answer so..

I bought a 2009 Beneteau with a Yanmar 3JH4E and going through my list of checks the other day I noticed the coolant level in the coolant recovery tank was below the LOW mark. While the engine was cold, I checked the coolant level in the heat exchanger and it is topped off (actually leaked out a bit) so I know coolant is full and likely do not have a leak. Also, because this boat is new to me I do not know what coolant was used prior and do not want to mix coolant types as that may cause an undesirable chemical reaction (sludge build-up).

I have both the original operation manual and the service manual. In looking at both I found conflicting info:

Operation manual states: Check the coolant level in the coolant
recovery tank. The level should be at the FULL mark. Add coolant if necessary. Remove coolant recovery tank cap to add coolant if
necessary. Do not add water

Service manual states: Check the coolant recovery tank when
the engine is cool and refill with fresh water as necessary to bring the water level between the low and full marks.

Uhm. Ya... that is a head scratcher. Yes, I know I can do a full system flush but I was avoiding that for now as I have never done one (I know it is likely pretty easy) so I was going to top of the coolant recovery tank but now I am at a loss.

Should I just flush the whole system and put what I know is proper coolant mix 50/50 in the coolant reservoir and the coolant recovery tank? Even if I do, if it becomes low in the coolant recovery tank in the future should I use water or 50/50 coolant?

Advice welcome. Thanks folks.

Like all new owners of previously owned goods (boat, car, house, etc.), you need to establish a baseline of all maintenance activity and move forward.

Unless the previous owner gave you the boat's maintenance log or told you what he used I would replace the coolant. It doesn't need to be Yanmar but should meet their specifications. Be sure to note it in your log. Once completed check periodically to see if their are any leaks or it is being consumed.

~ ~ _/) ~~ ~ MJH

[NorthCoastJoe]

As stated earlier I would change the coolant so you have a baseline.
I use a brand name ( Prestone ) antifreeze mixed 50/50 with distilled water and fill the engine completely. The tank that has a high low mark on it is just an overflow tank to handle the coolant expanding and contracting with normal use. I would just keep that tank in between the marks when the engine is cold. If you go above the high mark the overflow tank will overflow when the coolant expands.
In my past, I rebuilt engines as a job and we never made a big deal about brands of coolant. Most modern antifreeze is good with all engines. I have, Yanmar, Isuzu, Beta, diesel engines in boats, Ford, Honda, Toyota, Massey-Ferguson gas engine in trucks/cars/ tractors/motorcycles, I use the same Prestone coolant in all.
It should not be a big deal.

[a64pilot]

I’m still of the flush the snot of it, old school I guess, now when I say flush, I mean with plenty of clean water, no chemicals. My coolant looked fine when I bought the boat, but had some fine rust in the coolant tank. I’m sure it had a previous issue and the coolant was drained and refilled, leaving of course a lot of rust in the system, actually the heat exchanger was replaced. When I disassembled the heat ex it also was rust covered, I flushed it vigorously and filled with HOAT or hybrid organic acid tech coolant.
It has no color that I can detect, the coolant that is. I believe it’s gotten so that there are so many different types of coolants, you can’t go by color anymore.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Personally I don’t like prediluted antifreeze as I flush and that means quite a bit of water left in the engine and if I fill with 50/50, it’s not 50/50. If I just drained and refilled then it would be.
This year when I cleaned the heat ex and flushed the coolant, there was still a small amount of rust powder, not much but I think I’m going to continue to flush until I see no evidence of even a fine covering of rust.
Most people do not take care of their coolant system, they ignore it until there is a problem, and then in my opinion more often than not it needs flushing, caused they ignored it until there was corrosion (rust)
I was initially going to go with a permeant antifreeze and add the additive as necessary and filter it.
However from a previous discussion with Thinwater a few years ago I have adopted an every other year take the heat exchanger apart and clean it and flush and change the coolant. It apparently takes very little salt water to contaminate coolant, and you can’t take a heat exchanger apart and not get any salt water contamination as the fresh and salt come together in the heat exchanger of course. An every other year heat ex cleaning also has so far kept it nearly spotless, no real build up at all.

I guess I need to run a gallon of distilled through after I flush now to get the drinking water out. I had always assumed if it was good enough to drink, it was fine for coolant.
Distilled water is cheap.

I know the old school Dexcool was fine, but don’t dare mix it with any other coolant as it would gel if you did, I have seen that. Early 90’s model GM cars as it was a GM product.

[sailcrazy]

As I mentioned, the Yanmar Mx Bulletin is very explicit on what to use, and what not use, for antifreeze. I'm glad to just follow their lead....and the ORANGE capped Prestone seems to be available most everywhere. Also, the issue of your overflow tank level may be due to it's location. If the PO remounted it, and to high (or low)above the engine coolant fill port, it might contribute to your concern. There have been several Cruisers Forum Blogs that talk to that issue.

[Djarraluda]

Key issues are the difference between Ethylene Glycol, common coolant product, or Propylene Glycol, food safe antifreeze for ice cream etc.
If mixed, you get a funk, jelly like strands form that is not good in the water passages!!
Do not taste test, ethylene glycol will damage your liver!
We used to have a commercial ethylene glycol manufactures (distilled) for our business and chose the colour. It is just a dye.
Ethylene glycol will oxidise in use, any exposure to air and it degrades, becomes acidic. That is why you change coolant. One other post here talks of measuring PH, this is the check for degradation.
Most coolants also contain ph modifiers to prolong the life.
Best recommendation is to test the coolant. Then flush and renew so you know what you have, a new baseline to work with.
Roger

[David B]

We use genuine Yanmar coolant in our 4JH4HTE - just to be safe. It is orange.

For the Cummins Onan generator, we use a coolant sold to us as suitable for that engine. It is blue, and is a concentrate.

Our Yanmar header tank has the same characteristics as mentioned here earlier. Fill when cold to the top level, and you will lose half of it when the engine is running. I just keep an eye on it , and ensure there is at least something in it, which means it usually is around the low level.

[Dymaxion]

Thinwater... any recommendations on flushing? Brand name? Drain then add flush chemical then rinse? Flush chemicals, run until warm then 24hr soak then rinse? In my cars I just use Prestone rinse kit, aluminium block with wet liners, other is steel block. No diesel experience yet, my Yanmar 1GM10 is raw water cooled, scheming on how to "run until warm, then drain" that system. Tx

[Jamme]

Originally Posted by sailcrazy

With a Yanmar, be aware of the Yanmar Mx Bulletin regarding anti-freeze. Unable to find what I needed once I left the Medd and got here to the Caribb, I asked a certified Yanmar mech in San Juan, PR I had doing some work on my engine. He said just use the Prestone Dexcool WITH THE ORANGE CAP-premixed to a 50/50 mix if available.

+1.

See also Mack Boring & Parts memo:

https://www.cruisersforum.com/forums...-201637-2.html

[GeneM]

I had coolant problems and scratched away a bunch of hair. After much time, the solutions came to me.

My fill tank pressure cap leaked always. Pressing on the cap, I could see that the cap wasn't seating. After much bad advice, I simply bent the cap cam tabs so the cap was pulled down tight. It worked and the cap functions perfectly.

I also had a reservoir that wasn't functioning. An anecdotal comment from some forgotten source said that the reservoir has to be at the same level as the tank (fill cap is on the tank).

My reservoir was about 2 ft below and had a 4 ft small house to the cap neck. I moved it up and close and it functions perfectly now.

The best part of this was earning self-righteousness, being justified in criticising the original designers.

[regex]

Originally Posted by thinwater

Since most engines switched to OAT/Dexcool type chemistries nearly 20 years ago, it is increasingly unlikely that it is anything grossly different. Just drain and refill. Then drain and refill every 2 years. If you drain and refill on a schedule, flushing is not needed. Easy.


To a large extent, the flushing mantra evolved from ancient history:

a. High silicate AF, which is long gone.
b. Using hard tap water for blending and top off. Combined with high silicate, you got lots of scale.



Now we have ultra low silicate and use distilled water. No scale unless a contaminant is added.

I didn't know that. Excellent! Thanks for the info. I will fill with distilled (I am moving the boat this weekend) and then drain and refill in the next week or so (just so that I have a record of when it was last done and with what product). Thanks again.

[a64pilot]

I know it may be overkill, but I wouldn’t leave straight water in it for a week or so, largely because that so sometimes is longer than we would want.

[Recy]

b. Using hard tap water for blending and top off. Combined with high silicate, you got lots of scale.

Can anyone explain what scale is.

[thinwater]

Originally Posted by Dymaxion

Thinwater... any recommendations on flushing? Brand name? Drain then add flush chemical then rinse? Flush chemicals, run until warm then 24hr soak then rinse? In my cars I just use Prestone rinse kit, aluminium block with wet liners, other is steel block. No diesel experience yet, my Yanmar 1GM10 is raw water cooled, scheming on how to "run until warm, then drain" that system. Tx

I do NOT recommend flushing unless the system is clogged with scale. I was part of the ASTM committee, talked with the head engineering guys at the big manufacturers, and none were fans of flushing. It is easy to do more harm than good.

[thinwater]

Originally Posted by Recy

b. Using hard tap water for blending and top off. Combined with high silicate, you got lots of scale.

Can anyone explain what scale is.

https://en.wikipedia.org/wiki/Limescale


Silicate can also combine with lime (calcium silicate is insoluable). In engines, heat triggers scale precipitation.

[Djarraluda]

Originally Posted by Recy

b. Using hard tap water for blending and top off. Combined with high silicate, you got lots of scale.

Can anyone explain what scale is.

Minerals that were dissolved in the water. Very common in hard water areas, limestone regions.