We have an 89 HP Kubota Diesel engine in our brush chipper at work. We have had it for almost two years so I figure it is time to change the coolant. I have heard that diesel engines use different coolant than gas engines. Is this true?

The coolant in the Kubota is green if that makes any difference.

-Matt

 

From what I've been told, Its not so much that its diesel, the difference comes because of the reaction between aluminum and cast iron parts. Get two different metals, put a mildly acidic fluid between them, and a little movement, you have a battery! The gold, orange anti freeze justs resists this better than green.

 

Diesel engines are subject to "cavitation erosion" of the cylinder walls if proper additives are not presant in the coolant. This erosion can eat holes clear through the cylinder walls. Use a "precharged" coolant formulated for diesel engines, usually not green.

 

But the coolant in this engine IS green.

-Matt

 

You can get the additive for your coolant at heavy duty parts stores like NAPA and they also have test kits for this. It also has to be boosted periodicaly so keep a check on it. I run 2 semi trucks and we add a pint off treatment every 15000 miles if needed. Ive lost 2 engines to cavitation before I started keeping a check on It.

 

I have a '97 F-350 with the 7.3-liter PowerStroke Diesel. It uses "green" coolant also. I believe the "purple" coolant is for the newer diesel engines. Your best bet is to use the same type of coolant already in the cooling system. "Green" coolant is an ethylene glycol-based coolant and is an aluminum-compatible anti-freeze.

When in doubt about what type of coolant to use, check your owner's manual.

 

If you are using standard green coolant in a Powerstroke you better make sure you use some of the anti cavitation additive on a regular basis or you may be very dissappointed someday that you didn't.

 

Bobcat is using orange coolant and states not to mix with any other color of coolant.

 

Green coolant is "normal life." Orange/Red/Purple is "extended life."

Said because "green" coolant "had" to be changed every other year in older cars, whereas the O/R/P could be run for 5 years/100K miles before change.

The chemistry between the two is considerably different. The O/R/P uses what's called "oxalic acid chemistry" to extend the change interval. It's REMARKABLY sensitive to oxygen exposure, and too much will destroy the extended-life functionality, and possibly incur radiator damage. This is why you have see-through coolant reservoirs, and no more radiator caps.

"Contamination" of more than 10% "green" in O/R/P coolant will convert it back to "ordinary green."

Maintenance of Nitrite levels is what prevents cylinder liner cavitation/pitting/erosion, regardless of coolant base chemistry.

In big rigs, "extended life" has been stretched to 300K miles, or 600K miles with an "extender" treatment. Observational and operational evidence suggests that this is possible with yearly coolant filter changes, with "need release"-style coolant filters. Note that "extended life" can also be had from normal "green" coolant with this kind of filter system, also. Also note that in many rigs, hose life is shorter than the coolant life, so "extended life" is something of a mis-nomer.

-blaine

 

Well, I double checked the owner's manual today and it said to use the above coolant (which is green). So, I am going to drain out the rad and top it up with a 50/50 mix of coolant and water.

Does this diesel engine NEED to have an additive. It doesn't say anything in the manual about it. I want to be 100% sure before I start taking out the "old stuff".

Thanks again....

-Matt

 

Using an anti-cavitation additive, like NapaKool, is highly recommended.

 

OK, I want to be 100% sure before I do this coolant change so please bear with me.

I found a coolant that is made for diesel applications. It is the green coolant that is required for this engine. It also is has the SCA charge already in it (I think that's what it is called).

So, should I use that? It costs about $16 (Canadian) for a gallon.

Does that sound right?

-Matt

 

BUMP!

Anyone?

-Matt

 

Why not go to the Kubota dealer and get what they have?
With that said, I would guess that the coolant you are considering would be adequite for the task.

 

I thought about that. But, I figured the coolant I am looking at would probably be fine and cost about 10% the price of the Kubota coolant.

-Matt