Which anti-freeze / coolant in a Yanmar YB20 mini excavator with 3T75H-LTBS (K2032) engine?

[Jaap]

Last week, you guys helped me out in finding the engine code for my old Yanmar YB20 minidigger (transformed in a tracked fork lift). I think it's a machine from the eighties.
I managed to get a replacement waterpump, again thanks to the replies on this forum.
Now I have to decide which coolant I will use. I do have a very old (German) service manual for the YB20, but it only specifies the mixing percentages of water and anti-freeze, depending on the outside temperature. As far as the type of coolant / anti-freeze is concerned, it only states: "Use only a brand anti freeze or summer anti corrosion protection" (in German: "Nur Markenfrostschutz oder Sommer Korrosionsschutzmittel verwenden").
It does not specify any particular codes.
Of course I could check which color is in it now, but I doubt if that is even the correct type.
I want to flush the cooling system/radiator when I replace the waterpump, and after flushing I would like to fill it with the correct type of anti-freeze / coolant.

 

[ponytug]

Sometimes German phrasing in german makes me smile. Over here, those statements from the manual would get labeled with "them's weasel words, son."

Choosing a modern antifreeze for an old engine is not easy or precise in my opinion. Do you have a brass / copper or an aluminum radiator?

In the US, there are "modern" "green" aka "old" formulations for old motors. I know of some people who have decided to use more modern colors (generally OAT or POAT or PHOAT) in their engines based on cast iron + aluminum water pumps + radiator metals not being well addressed by older coolants. I would remember that the "old green" coolant has a fairly short replacement interval compared to more modern coolant formulations. My only strong advice is to flush the old coolant well, use distilled water for the final rinse of the existing coolant, and to use distilled water if you are diluting concentrate. My minor advice is that here there are widely available test strips to test the state of the coolant chemistry. I would not be surprised if your first change to a new coolant, regardless of type, wears out more quickly than the label states.

All the best,

Peter

 

[bmaverick]

Last week, you guys helped me out in finding the engine code for my old Yanmar YB20 minidigger (transformed in a tracked fork lift). I think it's a machine from the eighties.
I managed to get a replacement waterpump, again thanks to the replies on this forum.
Now I have to decide which coolant I will use. I do have a very old (German) service manual for the YB20, but it only specifies the mixing percentages of water and anti-freeze, depending on the outside temperature. As far as the type of coolant / anti-freeze is concerned, it only states: "Use only a brand anti freeze or summer anti corrosion protection" (in German: "Nur Markenfrostschutz oder Sommer Korrosionsschutzmittel verwenden").
It does not specify any particular codes.
Of course I could check which color is in it now, but I doubt if that is even the correct type.
I want to flush the cooling system/radiator when I replace the waterpump, and after flushing I would like to fill it with the correct type of anti-freeze / coolant.

Older machines typically ran on the old green color formulas.

The new Long Life coolants have LESS corrosion protection.

The only coolants we have today to work in old engines with the full corrosion protection like the old formulas are,

For Heavy Duty Diesel, only their G05 formula . . .

Zerex Valvoline Original Green, (the old stuff)

These two brand formulas can be found in North America and in the UK.

 

[ponytug]

@bmaverick not trying to stir things up, but do you have data on the corrosion protection attributes? Is this based on real world owner experiences that can often differ from theory or lab testing?

I'm asking because I have a variety of older engines and follow owners forums for them where the coolant discussions tend to degenerate into "my brand of truck religion is better than yours" and I would love some data (owner experiences, lab testing, whatever). Some of my older machines are somewhat specialized and would not be inexpensive to re-power or replace, making my choice of coolant very important for their longevity. I am aware that diesels, especially older diesels can have significant chemical challenges for their coolants. That said, I have one unit where the manufacturer recommended coolant just is not very good in the field, ok it sucks in my opinion, even at the manufacturer recommended 6 month to 12 month coolant change interval. (And that service interval is less than great, too, but I would do it if the anti-corrosion and anti-decomposition additives were effective, which they aren't, at least in the collective owner experiences.)

I do recognize that Yanmar has some design and engineering differences from other manufacturers that might make the coolant chemistry perhaps more specific to Yanmar.

All the best,

Peter

 

[bmaverick]

@bmaverick not trying to stir things up, but do you have data on the corrosion protection attributes? Is this based on real world owner experiences that can often differ from theory or lab testing?

I'm asking because I have a variety of older engines and follow owners forums for them where the coolant discussions tend to degenerate into "my brand of truck religion is better than yours" and I would love some data (owner experiences, lab testing, whatever). Some of my older machines are somewhat specialized and would not be inexpensive to re-power or replace, making my choice of coolant very important for their longevity. I am aware that diesels, especially older diesels can have significant chemical challenges for their coolants. That said, I have one unit where the manufacturer recommended coolant just is not very good in the field, ok it sucks in my opinion, even at the manufacturer recommended 6 month to 12 month coolant change interval. (And that service interval is less than great, too, but I would do it if the anti-corrosion and anti-decomposition additives were effective, which they aren't, at least in the collective owner experiences.)

I do recognize that Yanmar has some design and engineering differences from other manufacturers that might make the coolant chemistry perhaps more specific to Yanmar.

All the best,

Peter

I have a contact within Valvoline. For old engine cooling systems, this is the information shared. The contact did mention the Prestone product has good corrosion protection as well.

As for how the coolant change intervals are to be done, this would vary on the material makeup within the system.

We know cooling systems with components of copper and aluminum exposed to the fluid would cause galvanic corrosion in time. Even cheap freeze block plugs are weak in this area too, likewise water pumps. Most of the school buses on the roads today are mixed systems with mixed metals requiring full corrosion protection. Typical bus garages change fluids every 6 months. To answer your question on the change interval depends on the exposed mixed metals in the machines cooling system. You would have to make a determination based on the maintenance of components each machine has in the cooling system. Or do as the bus garages regardless and flush every 6 months like clock work. Now, the buses are daily drivers, typically 5-days per week. Your machine may go 12 months for a coolant change interval. I wouldn't go beyond 12 months personally. Those micro metal particles sitting in the suspended coolant over time do interact. The corrosion inhibitors are like anti-bodies and will neutralize the metal ions in the microscopic way . . . until the corrosion inhibitors are all used up. Then it's time for a FLUSH and refill.

I only know the Long Life coolants are engineering/formulated for vehicles made after 2001. Those on-road vehicles are mainly aluminum and steel cooling systems. The Long Life coolants will also ATTACK the metals in old machines and turn the coolant to brown thick sludge, often like the Dexcool ordeal and the several class action lawsuits with it.

I don't go by opinions. I go by the facts and real claims of a product. The Prestone says 10 years. I would still flush and fill in 12 months to ensure the corrosion inhibitors were not used up. Prestone has the highest corrosion inhibitors in their formulas, For All Makes and Models. Classic car owners trust it for this very reason.
Even the Prestone MAX, for classic owners is trusted today.
Prestone® MAX Cooling System Fix & Boost | American Vehicles

But we have Japan made tractors . . .
OK, then use this since @California says we can find all kinds of parts from Nissan/Datsun and Mazda 1970s models for our Yanmars.

Vehicle Specific English

prestone.com

Let's try this then for a 1972 Datsun Pickup,

 

[ponytug]

Thanks! That generally lines up with what I know from other sources, though I would clarify that the DexCool issue seems to have been caused by incomplete flushing, from what I read.

All the best,

Peter

 

[RjCorazza]

Thanks! That generally lines up with what I know from other sources, though I would clarify that the DexCool issue seems to have been caused by incomplete flushing, from what I read.

All the best,

Peter

The initial failure of DexCool in my understanding, was that it reacted with air in non sealed coolant systems. GM engines without a pressure cap on the recovery tank would inevitably sludge up the whole system.
I bought a low mileage GM Montana van that was on its second engine after a failed cooling system destroyed it. The dealer flushed the system and put DexCool back in with the engine replacement (prior to me buying it). The first thing I did was flush the DexCool thoroughly, and replace it with something else (forget what I used), and we drove that van for 200k miles.

You are correct that mixing just about anything with DexCool will cause sludge to form, which has trashed a lot cooling systems and engines.

 

[Jaap]

I was (just now) able to purchase a 246 page English service manual for Yanmar 3T75 (H)LE series. There is about 8 pages about the cooling system and also specs for the coolant / anti freeze. I will attach the part about the cooling system to this reply.

 

[ponytug]

I was (just now) able to purchase a 246 page English service manual for Yanmar 3T75 (H)LE series. There is about 8 pages about the cooling system and also specs for the coolant / anti freeze. I will attach the part about the cooling system to this reply.

Which would bring back the weasel words in english...

I think @bmaverick's advice on the coolant with additives sounds like the way to go as the manual above references adding additives, which is a particular chemistry.

All the best,

Peter

 

[bmaverick]

I was (just now) able to purchase a 246 page English service manual for Yanmar 3T75 (H)LE series. There is about 8 pages about the cooling system and also specs for the coolant / anti freeze. I will attach the part about the cooling system to this reply.

The manual is on the YTOG for free. Bummer. I could of saved you plenty of $$$.

YANMAR T-LE ENGINE SERVICE MANUAL 2T72HLE 2T75HLE 2T90LE 3T72HLE 3T75HLE 3T80LE 3T90LE.pdf

The LE only means the engine is used in a stationary application like a power generator or mounted on a trailer for mobile power genset.

The YTOG also has the 3T75__ for the YM tractors.
YANMAR 3T75HA YM226 0CT10-M22301_en.pdf
YANMAR 3T75HA 3T75HA-M YM220 YM220D YM250 YM250D 0CT10-M21801_en.pdf
3T75HL-DC.pdf (on request only) used in a DenYo Excavator