Yanmar 6BY2-260HP Coolant

[Tugbuyer]

Sorry to bring this up again, as I am aware there are several related note strings, but I wanted to get a FACTORY opinion on the type (Brand/formulation) of coolant to use in a 6BY2 Yanmar diesel. As I understand, Yanmar branded coolant is not available in the U.S. so it mandates an alternative. Can I get a recommendation from the factory? Thanks.

Dan
Sea Weed (R-29)

 

[SGIDAVE]

Sorry to bring this up again, as I am aware there are several related note strings, but I wanted to get a FACTORY opinion on the type (Brand/formulation) of coolant to use in a 6BY2 Yanmar diesel. As I understand, Yanmar branded coolant is not available in the U.S. so it mandates an alternative. Can I get a recommendation from the factory? Thanks.

Dan
Sea Weed (R-29)

Hello Dan,

On questions such as this, where a "failure" could be traced back or 'blamed' upon use of the wrong coolant, oil, fuel, etc. I believe it wise advise to ask what the MANUFACTURER recommends. At this point in time the Factory and Yanmar do not have a 'working' relationship, so taking their advise or my advise or anyone on the forum's advise would be imprudent. Think in terms of what you would say to Yanmar if you had a coolant related failure (that is, "why did you use THAT coolant?)...so, best to get your coolant recommendation from Yanmar...

A quick internets search yields a Yanmar Service Bulletin from Mack Boring which states:

COOLANT ADDITIVES
After testing some popular coolant/anti-freeze solutions, we have reached the following recommendations. It was not possible to test all brands on the market, so there may be some solutions that are acceptable but have not been tested. However, caution is advised if using other than approved brands.
Regardless of the recommendation of the coolant/antifreeze manufacturers it is YANMAR'S requirement that the solution is changed every 500 hours (On the YANMAR Model 6LP 250 hours) or once a year whichever comes first.
We do not recommend any other additives be added to the cooling system. Purified or distilled water mixed with the approved coolant/anti-freeze is the only protection approved by YANMAR. Concentrations of the Enix-ture should follow the recommendations of the manufacturer. The coolant/anti-freeze must be compatible with aluminum.

Advantages of this type of coolant:
• Improved water pump life due to reduced water pump seal wear resulting from fewer abrasive dissolved solids.
• Reduces hard water scale.
• Offers excellent protection against pitting corrosion caused by cylinder liner cavitation. Better
heat transfer than conventional coolants with regular SCALE additions.
• No silicate gel formation during use or storage.
• Outstanding hot surface aluminum protection.
• Superior protection in high operating temperature conditions.
• Effective, long-term corrosion protection for aluminum, brass, cast iron, steel, solder and copper alloys.

The coolant/anti-freezes that have been tested and approved are shown below:

• Texaco Long Life Coolant Anti-Freeze both regular and pre-mixed Product codes 7991 and 7998. This product is available in gallon containers, drums and bulk. It is recommended that the cooling system be drained and flushed before filling. Only Texaco Long Life Coolant should be used for top-off. This product has a much longer shelf life than conventional coolants provided the integrity of the container is maintained. For additional information and availability contact Texaco at 1-800-782-7852.
•Havoline Extended Life Anti-Freeze/Coolant. Product code 7994. This product is available through Texaco gas stations, Procedures are the same as with Texaco Long Life Coolant Anti- Freeze.
• Dex-Cool Long Life Coolant. This product is available through GM service centers worldwide.
• Prestone Extended Life Coolant. Product code AF888. If the above coolants are not readily
available, Prestone Extended life coolant is satisfactory.

Mack Boring & Parts Company Headquarters: 2365 RT.22 Union, NJ 07083 PH 908-964-8475, FAX 908-964-8475, WEB http://www.mackboring.com

I think you are safe putting any of the above into your Yanmar. Again, this is MY approach to questions like this. Opinions abound regarding which oil is best, synthetic v conventional, additives, etc. If your engine is still under warranty - it's best to follow the manufacturer's recommendations.

dave

Link to the whole bulletin. The coolant recs are on page 4.

 

[Andrew Custis]

We always used the Yanmar coolant in the Yanmar engines. It should be able to be ordered from any Yanmar dealer. I did see many times when the engines came with a blue coolant which I could only relate to a possible BMW coolant. I agree with the recommendation to follow Yanmar's direction.

 

[R Baker]

I went thru a similiar series of questions regarding which coolant... In my case the engine was more or less full ( I think) of the Havoline long life - dex cool , product. I needed more and it is not readily available here. So based on the Mack Boring bulletin; can one assume the coolants they mention - if a dex cool type - can be mixed ? This sort of nonsense was never a problem in the good old days - ah, but most things now contain an element of rocket science .

 

[Levitation]

Yup, it is an irritation to me also - old and set in my ways.
While I understand (superficially at least) the differences between the various colors having to keep straight which engine needs what color is too much of a pain to tolerate.
So when a new (to me at least) engine is added to the fleet I let sleeping dogs lie as long as the engine does not need antifreeze added.
When it does it is drained, flushed, and refilled with green stuff - end of problem :mrgreen:
While I understand the concern for warranty repairs the Charlotte Ann is long ago out of warranty so green stuff it is.

 

[Irish Mist]

If you are not sure what is in your engine for coolant. It might be best to drain it and re fill with one of the listed ones. I found the Havoline at a garage supply shop and that is what I have been using..Not sure what mixing different ones would do.. Probably nothing if an emergency. But draining and filling would be my recommendation. Then you know what's in it and when it was changed last.

 

[Crewdog]

BMW coolant is listed in the Yanmar manual as an acceptable coolant, and is readily available at BMW auto dealer parts counter, or amazon.

Got to mix 1:1 with distilled water.

have used for past 2 seasons.

It's blue to match the hull.

 

[Levitation]

Using what ever is at hand to get you back to port will work just fine no matter the color - actually, just plain water will be the safest...
If it is not the same as was in the boat, once at port drain and flush and replace with the color of your choice.
The new chemistries - DexCool and other long life types - are mostly organic acid based and not compatible with ethylene glycol (green stuff) in the long run.
We change our green stuff every third year on the farm in the big equipment. Never have a problem I am aware of and many of our engines are pushing on towards 30 years old. Our oldest is 1948 and doing fine on green stuff.
The Duramax diesels are coming up to time to replace their factory Dexcool. They will get green stuff on the refill.