Simple question about coolant recovery tank

[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.

[dannc]

When was the coolant changed? Is it time for new coolant?

For my own piece of mind, I would change the coolant so I would know what was changed and when.

You want to use the coolant chemistry specified by Yanmar. That does not mean you have to use Yanmar coolant, just a coolant of the correct chemistry.

You don't want to mix coolant chemistry. I have run John Deere coolant, in my John Deere tractor, which has a Yanmar engine, and used the same JD coolant in my Ford diesel truck. Both the Yanmar and my Ford/International engine use the same chemical coolant.

You can't go by the color of the coolant to determine chemistry.

I would prefer to NOT add just water and follow the operation manual. However, better to have the correct fluid level than low fluid. It would be best add the correct mix of water and coolant to the recovery tank.

I have been buying 50/50 coolant because we are on a well and have hard water. It is just easier to buy the 50/50 coolant, and while it costs more, I don't have to worry about what the hard water is doing to the coolant system.

Later,
Dan

[slug]

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.

Coolant evaporates , permeates hoses

If you add more coolant you change the chemistry of the original coolant

By adding distilled water you maintain the original specifications of the coolant

Coolant doesn’t last forever

Follow your service manual for coolant change times

[a64pilot]

Yanmar is and I believe has been for a long time Dexcool. Many people have it in for Dexcool, claiming all kinds of issues, but it’s a good coolant as long as you don’t mix it and keep it full with no airspace in the engine.
Dexcool is orange, and unless you know what you have is Dexcool, I’d recommend adding clean water or flushing the system, and flushing doesn’t mean drain and refill, it means installing a flush kit and flushing it until there is no taste or color, then running the engine up to operating temp and being sure there is still no taste or color.
If your going to do all that, you would be foolish in my opinion not to pull the heat exchanger tubes and give them a good cleaning too, before you fill with coolant.
When I flush I look up the total system capacity, then add a half gallon for the water heater and lines, cut that in half and add that much pure coolant back to the engine and add any water if possible to top it off.
The reason is no matter how hard to you try to drain it all out, there is still quite a bit of fresh water in the engine and if you add a 50/50 mix then it will be way watered down.
In my opinion I would rather have a rich mix of antifreeze than a watered down one.
Best actual coolant is pure water, antifreeze raises boil point and resists corrosion and water pump lube etc, but water is a better coolant. But to me corrosion prevention is very important.

[a64pilot]

I believe the real answer is be between full and low, just like oil level, but I like to keep my levels at full because if there is ever a leak I figure it’s best to start at the full mark.

[slug]

Originally Posted by a64pilot

Yanmar is and I believe has been for a long time Dexcool. Many people have it in for Dexcool, claiming all kinds of issues, but it’s a good coolant as long as you don’t mix it and keep it full with no airspace in the engine.
Dexcool is orange, and unless you know what you have is Dexcool, I’d recommend adding clean water or flushing the system, and flushing doesn’t mean drain and refill, it means installing a flush kit and flushing it until there is no taste or color, then running the engine up to operating temp and being sure there is still no taste or color.
If your going to do all that, you would be foolish in my opinion not to pull the heat exchanger tubes and give them a good cleaning too, before you fill with coolant.
When I flush I look up the total system capacity, then add a half gallon for the water heater and lines, cut that in half and add that much pure coolant back to the engine and add any water if possible to top it off.
The reason is no matter how hard to you try to drain it all out, there is still quite a bit of fresh water in the engine and if you add a 50/50 mix then it will be way watered down.
In my opinion I would rather have a rich mix of antifreeze than a watered down one.
Best actual coolant is pure water, antifreeze raises boil point and resists corrosion and water pump lube etc, but water is a better coolant. But to me corrosion prevention is very important.

Distilled water as a coolant will destroy a modern Diesel engine

https://www.cumminsfiltration.com/sites/default/files/pdf_archive/pdfs/product_lit/asia_pacific_brochures/3300963A.pdf

https://www.cat.com/en_US/by-industry/marine/marine-product-support/engine-advice/cylinder-liners.html

[a64pilot]

Well first I never said use distilled water, or use just water, but I did say water cools the best but causes corrosion.
Now without looking cause your link doesn’t work for me and has the forum formatting messed up somehow, but I’m going to suspect it’s going to show me pictures of cylinder liner cavitation, which is an issue, more so on some engines that others, Ford Diesels are particularly susceptible, and those guys test the PH of the coolant to see if they are having a problem, and add an additive made just for preventing cavitation if the PH is not to spec.
However usually distilled water is recommended to add to coolant, but I think it’s overkill.

https://www.dieselhub.com/maintenance/cavitation.html
Most Yanmar’s that I know of unfortunately are not wet sleeve motors and therefore are not susceptible, and as far as I know Yanmar does not recommend the additive made to help prevent cavitation, so I’m going to suspect it’s not an issue for Yanmar’s.


Plus it’s wet liners only, but only a foolish person runs pure water as a coolant if they don’t have to.
If you road race motorcycles, you have to and we drained the water after each race,to prevent corrosion.

[thinwater]

I spent 25 years in the coolant formulation business (manufactured glycol, tested coolants, one patent).


a. The current Dexcool is not the original Dexcool. It has been subtly reformulated to get around a few early short comings. So for get the old horror stories, they no longer apply. It's a good product, for both gas and diesel.


b. You don't need to flush unless you are dramatically changing chemistries. Just change what you can.


c. The marine change interval is driven not by the coolant wearing out, but by the risk of seawater contamination. So for get longlife and change it every few years.



d. Use only water of equivalent quality to what you would use in batteries (there is an ASTM spec). Not tap water and not from the watermaker.

[regex]

Originally Posted by thinwater

I spent 25 years in the coolant formulation business (manufactured glycol, tested coolants, one patent).


a. The current Dexcool is not the original Dexcool. It has been subtly reformulated to get around a few early short comings. So for get the old horror stories, they no longer apply. It's a good product, for both gas and diesel.


b. You don't need to flush unless you are dramatically changing chemistries. Just change what you can.


c. The marine change interval is driven not by the coolant wearing out, but by the risk of seawater contamination. So for get longlife and change it every few years.



d. Use only water of equivalent quality to what you would use in batteries (there is an ASTM spec). Not tap water and not from the watermaker.

Helpful, thanks. I am going to add distilled in the coolant recovery tank to make sure I have fluid levels where they should be. In the meantime, is there a way to test coolant chemistry? I have no idea what the previous owner put in the coolant system prior to me owning the boat. I have asked and he had a maintenance guy that I can't get any info out of so... should I do a full flush to be safe or can I test the chemistry somehow and simply drain and refill?

[dcarratt]

Orange coolant uses Organic Acid Technology (OAT), Dexcool etc. Green coolant uses Glycol. For topping up you should use the correct coolant at normal dilution. If you buy Yanmar it comes pre-diluted. If you top up with tap water you risk causing precipitation of sludge in the cooling system - not much, but it will build up. If you top up with distilled water you risk diluting the coolant over time and reducing frost protection. Probably OK to top up with distilled water if you do not have the correct coolant.

The "coolant recovery tank" is an expansion tank. When the engine is hot it should not be above the HIGH level. When the engine is cold it should not be below the LOW level. Most of the time it will be somewhere between the two marks.

As long as the coolant header tank is full, the level in the expansion tank is not very critical.

[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.

[thinwater]

Originally Posted by dcarratt

Orange coolant uses Organic Acid Technology (OAT), Dexcool etc. Green coolant uses Glycol. For topping up you should use the correct coolant at normal dilution. If you buy Yanmar it comes pre-diluted. If you top up with tap water you risk causing precipitation of sludge in the cooling system - not much, but it will build up. If you top up with distilled water you risk diluting the coolant over time and reducing frost protection. Probably OK to top up with distilled water if you do not have the correct coolant.

The "coolant recovery tank" is an expansion tank. When the engine is hot it should not be above the HIGH level. When the engine is cold it should not be below the LOW level. Most of the time it will be somewhere between the two marks.

As long as the coolant header tank is full, the level in the expansion tank is not very critical.

a. The ALL use ethylene glycol.
b. Nearly all formulation come prediluted these days. The industry came to realize that the quality of the water was too important to leave up to the customer.

[thinwater]

Originally Posted by regex

Helpful, thanks. I am going to add distilled in the coolant recovery tank to make sure I have fluid levels where they should be. In the meantime, is there a way to test coolant chemistry? I have no idea what the previous owner put in the coolant system prior to me owning the boat. I have asked and he had a maintenance guy that I can't get any info out of so... should I do a full flush to be safe or can I test the chemistry somehow and simply drain and refill?

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.

[Redline452]

For what it's worth, on my 4JH2TE, I can't seem to keep the coolant in the overflow tank any higher than the "low" mark - anything more spills out or vents off somehow. It doesn't go below the low mark, so I don't have a leak, but it just won't stay higher. Doesn't smoke, doesn't overheat, just likes an inch in the bottom of the tank. Local Yanmar rep/distributor didn't have any ideas either.

[dannc]

Originally Posted by dcarratt

Orange coolant uses Organic Acid Technology (OAT), Dexcool etc. Green coolant uses Glycol....

Don't judge the chemistry by color if buying different brands, at least in the US.

My John Deere tractor has a Yanmar engine. The JD coolant for that engine is GREEN.

My Ford/International engine came with a GOLD colored coolant that was the same chemistry as the JD Green coolant.

Ford also used a GREEN coolant that was NOT the same chemistry as the Ford GOLD or JD green coolant. One was not supposed to mix the Ford Green with the Ford Gold/JD Green coolant.

To further muddy the color issue, I think it was Fleetguard that had a coolant that could be used to replace the JD Green/Ford Gold coolant, and the Fleetguard color was orange.

My engines are now almost 20 years old, so as Thinwater says, maybe this is not as important as it once was, but I would still follow the manual, read the labels and be careful of the color.

Later,
Dan