Change the coolant once a year???

[Maynard Rupp]

Be vvvveeerrrrryyyy careful with that Cat permanent stuff (or the same deal from any other company - Cat's isn't anything special really, there are several "permanent" brands out there.)

It has two problems and one serious annoyance:

1. The additives deplete just like any other AF. You need to watch the inhibitor levels just like you do for any other product, AND you need to use the SPECIFIC test kit for that product. None other will work as the chemistry is totally different from the "traditional" nitrite-based stuff (it typically uses organic acids as its inhibitor, which is kinda wierd.)

2. For reasons not real well understood it tends to cause leaks where there weren't any before. Many people have had to go to all constant-torque clamps to keep it from leaking on their engines (these have springs on the winding portion, and maintain tension at all times.) If you start to see evidence of it leaking beware because this problem once it starts will require you to change ALL the clamps on ALL the hoses.

3. The annoyance - it is TOTALLY incompatable with traditional antifreeze. Period. You must make VERY sure to get ALL the old stuff out before you change to it, because when they mix they make a brown sludge that will plug up things you don't want plugged up - like water passages in the engine. Also, if some idiot ever puts traditional stuff in as a top-off, you're screwed. TAG THAT FILL CAP! Distilled water is ok for top-off of course but impacts the freeze point just like it does with traditional stuff.

-20F is a PITA, but you do what you gotta do. Were I in that climate I'd put the AF in there for the winter and run inhibited water during the boating season, and when I changed back to the water I'd drain and KEEP the AF. Basically, the AF would be a "storage" solution only - and the rest of the time sit in my garage.

I can't believe anyone would go to all the trouble of switching from anti freeze to water in the summer. My God man, Diesel trucks run one load of anti freeze for quite a few years and I am sure they put their DD engines through quite a bit more use than any boater. Between changing coolant twice a year, fuel polishing, rail adjusting, oil changing, and all the other problems I read here about DD engines I am more convinced that our Crusaders are the way to go. I wonder if you DD guys ever get out of the engine room to enjoy your boats.

[Genesis]

If you have drain valves (not petcocks) on your engines like I put on Gigabite it takes less than an hour to change the coolant like this.

The problem wiht Detroits is simply that the higher output ones don't have enough cooling capacity. They are marginal right out of the box, and get worse as fouling gets into the coolers, which of course it always does.

You have to realize that a "500HP" 6V92 has the exact same H/E tank on it that a 425HP one does, and likely is the same tank that's on a 280-300HP non-turbo motor!

You can't double the output without doubling the cooling!

[Maynard Rupp]

If you have drain valves (not petcocks) on your engines like I put on Gigabite it takes less than an hour to change the coolant like this.

The problem wiht Detroits is simply that the higher output ones don't have enough cooling capacity. They are marginal right out of the box, and get worse as fouling gets into the coolers, which of course it always does.

You have to realize that a "500HP" 6V92 has the exact same H/E tank on it that a 425HP one does, and likely is the same tank that's on a 280-300HP non-turbo motor!

You can't double the output without doubling the cooling!

Or halving the expecdted life span before overhaul??

[Genesis]

Oh, its far worse than halving..... a non-turbo Detroit will probably outlive YOU, even if run constantly on the pins. Try that on a turbo motor and you'll be lucky to make 1000 hours.

[captddis]

A few things to ponder. Our engines were filled with Texaco green antifreeze at Hatteras. My 1982 8V92s have always had Napa HD antifreeze in them. I pulled the factory kits this spring and they looked like new on the water cooled section. They had no rust, pitting or corrosion. I put Powercool in both engines but I am going to switch back to the low silicate antifreeze.
Detroit has had some problems with the powercool on the series 60 engines and does not reccommend its use in the 60 or any of the DDC/MTU engines.
The Nalcool/water combination is not very popular anymore either. If you go that route keep close tabs on the condition. If it is overdosed it eats the seals. I will not use it with aluminum ie generators.
As said before it does dissapate heat better and some marginal systems benefir from it. Most do not.
Cat has two coolant choices the Marine engine coolant and the ELC or extended life coolant which is basically Dexcool. The ELC has been problematic on some older engines. I always use the constant torque clamps no matter what coolant is used. They are superior.
BTW if you have Yanmars, you have to use the dexcool and change it regularly. It is critical on these.
Nothing wrong with replacing coolant frequently, but unless you run a thousand hours a year, the low silicate green coolant is fine.

[Walter P]

I recently drained, flushed with water, by refilling several times then running for a few minutes and re-draining each engine again. Finally when I felt that the muntiple rinses were ok, I refilled the engines with a 50/50 mix of DD Powercool as per the instructions. Actually the instructions said to mix with equal parts water and concentrate, but it specified TAP water rather than distilled. It seemed reasonable to me to assume that if tap water would be OK then distilled would be better. Do you guys agree with me or do you think that the probable minerals in tap water somehow balanced the mix better? Why would DD even mention tap water and not specify that distilled would be preferable?

Are we being too careful -

Walt

[Genesis]

Distilled water is preferrable. If you read the specs CLOSELY it says that tap water WITH LESS THAN A SPECIFIED TDS (dissolved solids) COUNT is ok.

Do you know what your tap water TDS count is? I don't. So I use water with a "zero" count - distilled!

Distilled water is what - 80 cents/gallon at WalMart? How cheap are we getting here by avoiding its use?