Diesel Coolant: OAT vs HOAT; Red vs Blue?

I'm about to reassemble my freshwater cooling system and am utterly confused as to which coolant to use. This is a 1977 Perkins T6.354. Recent articles on diesel coolant state a special "OAT" formulation is required to prevent pitting, especially with wet sleeved engines.

I believe this motor is dry sleeved, but I'm stuck in analysis/paralysis. After one article I should definitely use OAT, then another it's NOAT, then another it's HOAT, then another says it doesn't matter because they're actually dry sleeves. Then something else comes along and says I should use straight water with Redline WaterWetter or Purple Ice.

There was brown sludge lining some of the internal plumbing and I've read that's caused by the corrosion-protecting silicant precipitating out of traditional coolant.

I think I'm going to use 50% coolant and distilled water. For the coolant it's either Peak Final Charge NOAT ($28/gal undiluted) or Xerex G05 HOAT ($21/gal undiluted).

~ confused.

Yes the Perkins is dry sleeved.
I always used Prestone (or equiv).
And still do in my Lehman.

jleonard said:

I always used Prestone (or equiv).
And still do in my Lehman.

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Ditto. Standard Prestone in my Lehmans and its all they've ever had.

Ken

kchace said:

Ditto. Standard Prestone in my Lehmans and its all they've ever had.

Ken

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And recommended as OK by American Diesel...but the OP does have a Perkins....

My lobsterboat has a 6.354 in it, vintage 1972, I have always used std. Prestone or other std. name brand AF and never had a cooling sytem problem . IMHO, fancy AF are for use in newer lightweight, highly stressed engines, not old all iron engines.

You can use anything you find available which is rated astm d-6210. Don't use d-3306 as that's for gas engines.


Spell check via iPhone.

Your engine was designed around the timeline of standard green (low silicate) antifreeze. You should also use some type of SCA (supplemental coolant additive) like Wix, DSM, etc to insure the proper ph of the coolant. Once you mix your antifreeze with distilled water you should test its ph. And it should be tested once it's installed and every few months of use and even non use. There are kits out there to test ph and are really cheap. You can opt for testing a sample just like oil. This will tell you lots about you coolant. Things like ph, Iorn and rust content plus it's cooling / boiling points which are good to know. I learned this the hard way with my recent rebuild of a CAT 3208TA.

Most of us have old Iorn in our rides. We really need to maintain and look at our cooling systems closely. Like I said I'm learning the hard way that just cause it looks ok does not mean it is OK!

Capt. Jon, some good advice. Hope they listen to you...

What's "lorn"?

I saw somebody checking the voltage between the coolant and the negative battery terminal. Surprisingly it was .3 volts with old coolant. That tells me something galvanic is happening, but I wouldn't know if it's the protective effect of the zinc or bad corrosion happening. Seems like a good idea if there was a way tell which was happening.

R_p_ryan said:

What's "lorn"?

I saw somebody checking the voltage between the coolant and the negative battery terminal. Surprisingly it was .3 volts with old coolant. That tells me something galvanic is happening, but I wouldn't know if it's the protective effect of the zinc or bad corrosion happening. Seems like a good idea if there was a way tell which was happening.

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Sure makes me think that the coolant is too acidic and turned into a battery solution. However I have to say that's above my pay grade. Sure makes you think though.

D6210 is OAT

More confused

Capt. Jon said:

Sure makes me think that the coolant is too acidic and turned into a battery solution. However I have to say that's above my pay grade. Sure makes you think though.

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A reading of under .5 or so volts means the coolant is good as I recall.

From an article I researched...

Caterpillar Engines

Summed up by Doug Hunsicker


Meter reading:


0 to .3 volt is normal in a coolant of a cast iron engine. .5 volts will destroy a cast iron engine with time and engine manufacturers are reporting .15 volts will damage an aluminum engine with time.

But which spec to use, 3306 or 6210? 3306 is old style coolant and is found everywhere. Every coolant at the parts store is 3306 and there was one jug of 6210 that was very expensive.

This is why I'm unsure. People say buy traditional and OAT, which is 6210...

What concerns me the most is assembling an engine cooling system without knowing the difference between wet and dry sleeves, or what it has. With dry sleeves plain old distilled water is fine, just add some Nalcool. Distilled water cools better anyway. With wet sleeves you should pay more attention.

kulas44 said:

What concerns me the most is assembling an engine cooling system without knowing the difference between wet and dry sleeves, or what it has. With dry sleeves plain old distilled water is fine, just add some Nalcool. Distilled water cools better anyway. With wet sleeves you should pay more attention.

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Nalcool is HOAT.

So the forum has several votes for standard coolant (3306), one for OAT, and now one for HOAT.

Now I understand a recent article I read about different coolant types, tap water vs distilled and said none of it really matters as long as the coolant is tested periodically and the corrosion inhibitors are still active.