Forgive me if this is a dumb question, but do the Cummins engines need any kind of coolant additives? Coming from a 7.3 Powerstroke, I had to test the coolant with test strips every 6 months or so and replenish the SCA additive as necessary.

The engine currently doesn't have a drop of coolant in it and from what I've read here, the Zerex G-05 is the correct coolant for this engine. I plan on flushing out my radiator and heater core to make sure all of the old coolant is out before I put the engine in the truck and fill it, but wanted to make sure if there's an additive I need that I get it in there too.

 

I don't beleive it calls for one in the manual but doing it anyway shouldn't hurt anything I test mine and add treatment if needed.

 

Zerex G-05 and distilled water (50/50) and you should be good to go.

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The Cummins 5.9 doesn't need the SCA additive.

MikeyB

 

None required but I use ROyal Purple's "Purple Ice" and it really works to cool the engine quicker.

 

i ran water wetter really noticed a difference in cooling

 

That's exactly what I was looking for...and hoping to hear. Just one less thing I'm going to have to worry about. Thanks for the replies.

 

If you know the history of the truck and it has had regular coolant changes you would probably be fine to just drain and refill with G-05...no aftermarket additives needed. Not a good idea to mess with the chemistry of your coolant system, you don't want any sludge in there.

 

Well, the history of the truck I got my engine from goes something like this. In early 2004, the truck was totaled for some reason when it was brand new...fell of a transporter or something like that. The truck only had 5 miles on it. In mid 2005, A guy in Iowa bought that engine from a salvage company to do what I'm doing with it -- put it in a Super Duty. However, he never got around to doing anything with it at all so he sold the engine this spring and I bought it.

So, I've got a virgin 2004 engine, with only 5 miles on it, that only had coolant in it for a bit. It's been dry for quite a while. When I flipped the engine over on the stand to change the cam, there was not a drop of coolant that came out. I got nothing to drain and flush except my radiator and heater core.

 

I put the Royal Purple in my truck also, however I noticed my temps went up, only like 5*,(190 to 195) it drops the temps but not any faster than with out it. Under stand this, I only have the idiot gauge to go buy, and I have only had the RP in the truck about two weeks.

 

I've got Autometer Gauges, and I'll have a coolant sensor in the head to measure actual temp, so I'll see how it does. The Powerstroke radiator, which I'm reusing for this, is pretty beefy. Never once in 5 years did I come close to overheating. But I don't know how it compares to the Dodge radiators and whether or not the Cummins runs any hotter than my 7.3 did.

 

Coolant Additives are a waste.

As recommended by DEI, I poured in two bottles of DEI's Diesel Radiator Relief. Their product states that a 30 degrees drop in coolant temps are expected.

I did not see even a 1 degree difference.......saved your time and money and just run the recommended coolant.

 

I just go to Napa and get a bottle of Napakool, works great and isn't expensive.