Coolant

Need a bit of education from your big brains this morning. Finishing up our rebuild of our Heritage 40 and changed out the water pump. Noticed that our coolant level was low and that the previous owner had used a propylene glycol based coolant on our single engine Mercedes Nanni closed system. To be honest not once in my 50 years on the planet have I ever really paid attention to coolant types. When my car was low I just added more of what ever was available. So I went to the auto parts store and actually read the different coolant types all were ethylene glycol based. Searching the web I found quite a bit of conflicting information. One site said if you mix the two you wind up with basically mud in your engine, the other stated you can mix just fine. I actually found the correct fluid at West Marine but my question is what are the benefits to either? Thanks for your help! Marc

There will be "purist" here that will tell you to only use marine coolant as it is non-toxic to the environment or use the same color of fluid.

Last year I changed all the hoses on both CAT 3208T/A. I called CAT and they stated to me there was no real difference in coolant. I ended up using Preston in my closed system and works great. You can get it at Wal-Mart at about a third of the cost at WM.

Welcome to TF

Alaskan Sea-Duction said:

There will be "purist" here that will tell you to only use marine coolant as it is non-toxic to the environment or use the same color of fluid.

Last year I changed all the hoses on both CAT 3208T/A. I called CAT and they stated to me there was no real difference in coolant. I ended up using Preston in my closed system and works great. You can get it at Wal-Mart at about a third of the cost at WM.

Welcome to TF

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Good to know. Will hit up Walmart today. Thanks

Propylene glycol based antifreeze, the pink stuff, should only be used for winterization of raw water systems, potable water systems, air conditioner raw water systems, etc. You use a lot for this purpose so the lack of toxicity is important as it all gets dumped at the end of the winter, not to mention it is safe for humans to digest, an important consideration for potable water systems.

PG, pink stuff antifreeze, may have some anti corrosion additives, but not much I suspect. Also it doesn't have as good a boiling point elevation capability as ethylene glycol antifreeze.

So use EG antifreeze in your engine's coolant system. Any good brand is ok for that engine and if you stay within the same color spectrum- usually green, mixing brands is probably ok. Yanmars need special Dexcool stuff due to their aluminum exhaust manifold, but your engine uses cast iron I think.

David

I was not referring to the pink RV winterizing fluid. They make different types of coolants and they can be different colors. My CAT dealer told me that in most cases and in all cases with CATs it doesn't matter you can mix them. It is also on the Preston bottles.

Brian at American Diesel told me to use any quality coolant in my Lehmans.

If you check out the Yanmar discussions on Boatdiesel.com you will see many references to the official Yanmar strictures on coolant. Apparently, the significant presence of aluminum in the closed circuit influences their position. My Yanmar 6LPA-STD for instance requires change of the fluid biannually or every 250 operating hours. The chemical properties Yanmar wants as far as I can tell are available in Shell Rotella Extended Life Coolant. It is red. I use the pre-mixed version.

Interestingly, I found that using it in my little 3.5 KW Nextgen is not optimal. 30% Prestone (yellow stuff) and 70% water cools it better.

Actual Fluid

According to the log book and the extra fluids on board this is the fluid used on my boat. The boat has been in South Florida for over 20 years and I don’t believe has ever been winterized.

Glad to see this thread. A couple months ago I went to check coolant levels on my Lehman 120s before heading over to the fuel dock to pump out and saw this (photo attached)!!

Asked around and the only plausible answer I got was that I mixed ethylene and propylene coolant, but there was no clear consensus. I also recalled topping off with straight coolant a few months earlier, but didn't use very much. Maybe a quart or two. Still unsure of what occurred.

So I drained and refilled with "diesel formulated" coolant. Yes, a bit more expensive. So far, no return of the coolant boogers...

Buy the “5 year” stuff and the coolant strips that CAT sells and test your coolant annually. If you use coolant filters (Cummins has them) then replacing the filter also replenishes the additives. Diesels need good quality coolant to guard against the dreaded cavitation that can occur next to the cylinders which can cause overheating. This is also why you can’t use pure water. Shitty coolant is a prime cause of overheating.

You need to use the coolant chemistry that is recommended in the manual. Do NOT go by coolant color. Coolant color is NOT an indicator of coolant chemistry. You also do not want to use a coolant for a gas engine in a diesel engine.

For instance my Ford diesel had gold colored coolant but Ford also has a green diesel coolant. They are NOT the same chemistry and should not be mixed. My JD tractor, which has a Yanmar engine, uses JD coolant, which is green, and is the same chemistry as the Ford gold coolant. In the Ford engine I have used the Ford gold coolant and JD green coolant without a problem for almost 20 years. The Yanmar just gets the JD green coolant but it could use Ford gold.

If I remember correctly, one of the long life coolants, that has the same chemistry as the JD green and Ford gold coolants, was orange.

Read the labels to use what the manual says and don't go by color.

Later,
Dan

Xsbank said:

Buy the “5 year” stuff and the coolant strips that CAT sells and test your coolant annually. If you use coolant filters (Cummins has them) then replacing the filter also replenishes the additives. Diesels need good quality coolant to guard against the dreaded cavitation that can occur next to the cylinders which can cause overheating. This is also why you can’t use pure water. Shitty coolant is a prime cause of overheating.

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Brian Smith said the cavitation issue was not a problem in the FL120. Sleeved engines apparently have that issue.

Marc,
Do not mix coolant types (often, but not always shown by colour). If you do, you can get the "coolant boogers" as described by Moonfish. If you change types, make sure you flush the system before installing the new type to avoid any potential "reaction".

I am not familiar with your engine or that type of coolant, but I would advise you to contact the engine manufacturer (if you don't have the original manuals) to find out what (type) is recommended. I would feel fine using any reputable brand of coolant of the correct type in most cases. However, a few engines are very "fussy" when it comes to coolant. My Cummins is not fussy.
By the term coolant type, I mean, regular "green stuff", NOAT, OAT, Extended Life, etc.

Thanks

Thanks fellas. All good info. I guess I’ll start with the manual. Cheers

In older engines , where the block is the cylinder or where the block holds a replaceable liner the old green stuff works fine . Just change it every 2-3 years , and use enough to keep frm freezing.


In FL and other warm areas about 35% green and the rest distilled water you will get the best heat transfer and good corrosion controll.


More modern engines that use replaceable cylinders just held top & bottom the use of

SCA type AF is required. On every firing stroke these cylinders can ring like a bell which causes tiny bubbles to form on the outside of the cylinder walls which can cause cavity erosion , eating holes in the cylinder. The SCA style antifreeze leaves a thin coating on the cylinder wall which slowly gets eaten , and replaced , instead of your cylinder.


Truck stops sell kits to measure the SCA left in the AF , which can be added if needed.


Changing AF too often is no problem, except to your wallet , not often enough , even the old green AF can be dangerous as it can acidify.