Coolant Additives

[Genesis]

No reason at all, provided the specs are met.

[ThirdHatt]

Are there any other specs that I need to look for other than the DD 7SE298?

[Genesis]

I don't believe so.

The big deal is the inhibitor package, particularly on wet-liner engines (they are succeptable to cavitation corrosion.)

I use FleetCharge with Fleetguard's HD diesel antifreeze base myself, and distilled water. Cheaper than the DD solution, meets DD specs, and since I change it out every 2 years anyway, there's no point in paying for "extended life."

I'm one of those guys who believes that fresh coolant beats a "longer life" coolant. Trying to stretch coolant is kinda like trying to stretch oil change intervals, and can have the same sort of outcome if you get unlucky.... IMHO not worth the attempt.

[eze2bme]

I have a question about coolant. You say that you change yours every two years. Does coolant wear out or loose its properties from age or wear? I only run my DD 671N's about 125 hours per year. Thanks!

[Genesis]

Yes, to some extent.

Inhibitors do wear out. You can replace them if you want, but I like the idea of flushing the system every couple of years, and once the coolant is out, I see no reason to put it back in.

[REBrueckner]

It IS important that a diesel engine use the proper coolant recommend by the manufacturer. Different engine manufacturers may have different formulation requirements. Various serious problems can occur with improper formulations. In general, automotive antifreeze is NOT appropriate for heavy duty applications like marine diesel engines.

My comments apply to two cycle DD only. Both time and use will deplete inhibitor/additives. I've been told it's 53 series engines that have wet liners, NOT 71 series engines.

Never mix different antifreeze colors. Never add supplementary additive packages willy nilly to antifreeze. It must be formulated for such additions, as in some extend life antifreeze. Add the wrong mix together or different colors and brands and you can get precipitates.

For complete details on Detroit Diesel antifreeze, see " Detroit Diesel Coolant Specifications" 7SE298 under Detroit Diesel.com. Search "antifreeze" in the upper left hand corner, pick the above title (third choice.) This bulletin number is 7SE298, the spec is TMC RP 329....heavy duty...

When I last researched, I found at least four antifreeze/coolants that meet all DD specs:
DD Powercool and Powercool plus (long life)
ZEREX (618-1) extended life
ZEREX Pre-Charged
(These are not to be mixed.)
They will say so on the package.

Detroit Diesel recommends a 50/50 mix of antifreeze and deionized, distilled or demineralized water to prevent cooling system corrosion and prevent freezing. You want nitrites, but NOT nitrates, phosphates, nor silicates in your DD two cycle antifreeze. (If I recall correctly, it's the nitrite component that addresses crevice corrosion.)

DD Powercool or Nalcool may be used where freezing is not a concern.
Penray provides Nalcool additive package product for Detroit Diesel coolant system protection. Their website at http://www.penray.com is informative.

A few years ago I found Shoprite antifreeze (the Supermarket!) on sale in March at $1.99 gallon. Package said it met DD specs!!! I e-mailed Shoprite, they forwarded me to the antifreeze manufacturer...by gosh it DID meet TMP 329!!! So I stocked up, changed antifreeze in my engines, and have about six gallons left for "refresh". I have not found it again in my local store. I tried three different automtove stores: None had an antifreeze that met DD specs.

Admission: I used automotive antifreeze for 22 years in my old Matthews with 6V53's...never had a problem, did not know then what I know now. But I never ran them hard either and I think that makes a difference regarding cavitation corrosion.

[REBrueckner]

Further Clarifications:
(1) Don't use an automtive or light duty diesel antifreeze formulation in a DD diesel 53 or 71 series engine;
(2) Don't use another engine manufacturer approved formulation in a DD unless it says it also meets DD specs;
(3) Test strips (litmus like paper) are a convenient way to test for proper alkalinity. A coolant/antifreeze solution should generally be flushed and changed if found to be acidic.
(4) You can also test alkalinity via a voltmeter...don't have the specs here at home.
(5) Antifreeze protection does not fade with time, corrosion and inhibitor protection does wear with time,use and age and contamination.
(6) A easy compromise for antifreeze: add a half gallon of antifreeze and a half gallon of proper water every year to refresh additives. Check alkalinity every few years. Dispose of old antifreeze mix properly. (Ethyelene glycol is very toxic to maine life.)

[Genesis]

Yeah, don't dump AF in the water.....

92-series engines are also wet liner and need cavitation protection.

MOST heavy-duty diesel antifreezes will meet DD specs (and will so state on the label.) NO automotive ones usually do, as they're not formulated for diesels.

The color is just a coloring agent - some are red, some green, some orange, etc. I would not mix antifreezes from different manufacturers or "types" regardless of color; that the colors match does NOT mean they are compatable.

Some of the newer "ELC" style coolants (CAT comes to mind) are bad news in engines not built for them. The reason is that they are great at finding ways to leak out - the coolant is fine, but you need constant-torque hose clamps on EVERY hose connection or you WILL have leakage problems. Those coolants are expensive too - I wouldn't waste the money.

Never use anything other than distilled water for blending raw antifreeze and topping up a mixture. Tap water contains minerals which WILL drop out in the system and severely damage cooling capacity. If you don't mind the cost you can buy premix but its generally the same price per gallon (or very close to it) and you get half as much!

If you are not in an area subject to freezing temperatures you actually get the HIGHEST capacity for cooling by running distilled water with a proper inhibitor package and no antifreeze at all. Marine Detroits all run 7psi caps and have a maximum safe operating temperature of 185F - there is no need for high boiling point protection as there is in a car system that runs between 195-210F. This is perfectly acceptable under DD specs, provided you use the proper inhibitor package. DO NOT EVER run plain water WITHOUT inhibitors though - that's a certain way to destroy the engine.

Never run more than 50% antifreeze (the other 50% being water); you will overheat. Antifreeze is just that - antifreeze - it has far less heat-carrying capacity than water.

Coolant test strips are cheap BUT you must get ones that are designed for the formulation that you're using. Most - but not all - coolants get their inhibitor capability (corrosion and cavitation) from nitrites; check the label.

[MikeP]

Just another of those "be sure to check" kind of things. The pressure caps ("radiater caps") on our 53's 8V71TIs were 15psi caps rather than the 7PSI caps specified by DD. I assume the previous owner did that for some reason - perhaps because he couldn't find 7psi caps! I didn't notice it until after we brought the boat here.

Don't assume anything on a boat is right that you didn't do yourself.

[Passages]

Geeeze...I kinda wish I never read this thread.

I've been running a 40/60 mix of regular Prestone AF/distilled water in my 6-71's for years. Complete system flush with radiator cleaner every 3 years. Other than periodic acid cleaning on the RAW water side - never had a problem. Prior owner was doing the same and he owned the boat since 1981!

Granted, the boat only runs 75 hours/year in cool New England water, but after 25 years, I guess these ole' Detroits are more robust that you think (or maybe I'm just lucky).

I might give power cool a try in spring, but wonder at his point if it really matters -