So I have researched, read, perused and looked at way to many forums and thread posts on coolant. There seem to be no straight foward answers as to which coolant is best in the IDI.


I have learned there is a possiblility of a core melt down resulting in thermonuclear detonation if you use the wrong one!
Here is what I found.


Most people seem to recommend using a low silicate green coolant with a SCA (Supplemental Coolant Additive) AKA DCA (Diesel Coolant Additive).


SCA-DCA Which What - So many people seem to use the NAPA DCA, then about as many use Motorcraft DCA4 (VC8). Now I found out that NAPA DCA is not compatible with any other DCA4. However it seems the rest of the other DCA4 additives are compatible with each other.


Coolants


Fleet Guard from Peak, did not read anything to bad about it, one post had an "expert" that said it can eat seals. I don't know that just passing it along. Several people stated they use it and it works for them. Several more said to stay away alluding to the thermonuclear detonation.


ELC or Extended Life Coolant, not to many posts of people using it in IDI's, many with warnings that it eats seals - Thermonuclear
detonation.


Zerex G05 - MotorCraft Gold - Several recommendations for this coolant. It contains small amounts of silicates, but has a much longer service life than Low Silicate Green. Several said test and add DCA or SCA as needed.


Regular Green Low Silicate Most seem to be using this, a good national brand. Least of all warnings on thermonuclear detonation AKA cavitation.


What I decided to do was go with was 4 gallons low silicate green coolant, and 4 gallons of distilled water, 1 Pint of Motorcraft VC8 (a DCA4 coolant additive).


Everyone agreed to do a complete coolant flush if you change from one type of coolant to another, including removing the block plugs.


Name brand green in my area is like Gold Bullion or something, I went to Oreilly, only green available is house brand, not much data on it. Went to AutoZone, house brand does not state low silicate - neither offered a name brand green. Next WalMart, no green at all. Tractor Supply - no green, offered Fleet Guard but none in stock, Big Lots just because well maybe and no - Peak Long Life only nothing else. Finally ordered Zerex original green from Amazon, they sent Zerex ELC - YEP - returned that. Last stop Advanced Auto - Jack Pot CarQuest brand Low Silicate Green.


My reasoniong for green is; outside of the Gulf Coast of Texas, Green has to be about the most common coolant, and in the event there is coolant loss on my travels, green will be readily available so I can use it with distilled water and not have to worry about a complete coolant flush. I also went with VC8/DCA4 to be compatible with the other DCA4 additives out there for the same reason.


On my next go around I will probably switch to Zerex G05 with VC8, the G05 was available at Oreilly, Autozone, and Advanced Auto. In another year or 2 there should be more information on how well G05 is working.


I will also be installing a Coolant filter setup inline with one of the heater hoses, once I locate a good one, if someone has one I would like to know what you have and where you got it.


I hope this helps someone else who is trying to figure out which coolant and additive to use. Any input from anyone would be great! What coolant you are using and which SCA - DCA you use if any?

 

I don't think one pint of DCA4 will be enough for the whole cooling system. Test strip will tell you for sure.

 

I use Zerex HD ELC(Part number: ZXED1) in all my IDIs. No issues so far, I've had it in for several years now.
It's diesel engine rated, supposed to protect against cavitation etc, meets a number of company specs(john deer etc).

We've only got a couple of O-rings in our cooling system, which is the only 'concern' with ELC coolants... and, like I said, no issues thus far.

 

I think you are right, I saw where it was recommended to put 2 pints in, however I don't want to over do it. So I thought I would start with 1 and do as you say and test.


Thank you for the advice.

 

Very good to know, I think most of the concerns I read were concerning seals around the oil cooler.


It is good to get real life feedback on what is working as it looks like green is going to be phased out sooner or later.

 

I thought it was more like 2 quarts. But it's been a while since I've had to think about it; I'm running Fleet Charge in all three.

 

i have run nothing but regular old green antifreeze with napakool; in my 88 for the past 495,000 miles.
i want to say one quart per change. but it may be two, it has been a few years since i changed it as i do not daily drive it any more.

 

I am running Peak Final Charge in mine and it has been perfect thus far.

 

New member, and new idi owner here. Gonna revive this thread, cause I have some questions.

The previous owner of my '90 7.3 just used regular coolant (non-ECL) with no SCA. There's no smoke in exhaust, the coolant under the radiator cap looks bright green, and as far as I can tell, the engine runs well.

To protect against any potential/further cavitation, I'm planning to replace the old coolant with new coolant (more of the generic green stuff) + Motorcraft DCA VC8.


Here are the questions:

1. Will the Fleetguard CC2602A test strips be appropriate for testing for the VC8 in the coolant?

2. The truck currently has the CarQuest green coolant with note of "extended life - 150,000 miles / 5 years of protection". (The listed ingredients are Ethylene Glycol, Diethylene Glycol, Potassium 2-Ehtylhexanoate, Denatonium Benzoate, and Proprietary Inhibitors.) Since it doesn't say anything about special additives in the description, I assume it needs the DCA VC8.

The original post states that CarQuest makes a low silicate coolant - how would I know whether a coolant has low silicates and why does this matter?

3. (Bonus Question) As an interim shortcut, until I replace the coolant - what would it do to siphon out some of the old coolant and pour in some of the VC8?


Any insight would be appreciated - Thanks for reading

 

i would run it as is until you change unless you do not plan on doing the change for a few years.
cavatation is a hyped up white elephant.
it is not nearly as big of a problem as people make it seem to be.

 

Regular green Car Quest is good quality low SCA coolant , available at Advance auto stores.

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Fleetguard is not from Peak. It's been owned by Cummins Engine Co. for decades and it's an ELC that's compatible with 7.3 and 6.9 IDI's.

 

I use Fleet Charge and have been since I bought my IDI in 2011. Not a single issue to speak of so far. It does not eat seals. Anyone who thinks it does can come over and lick the bottom of my dry-as-a-bone oil cooler. Fleet Charge is also compatible with Motorcraft SCA if you need to top it off later down the road.

 

Q: What is meant by the term Fill-For-Life technology?

A: The Fill-for-Life alternative provides for easy, low cost monitoring of the coolant inhibitor and freeze protection levels. Fill-For-Life is an extended service maintenance program developed by FLEET CHARGE® and Penray researchers. It is very simple. Users simply install a Penray Need-Release filter on an engine coolant system (up to 30 gallons). Every 18 months the filter is replaced. This practice eliminates scheduled coolant changes.




https://www.peakhd.com/product-lines/fleet-charge/faq/

 

Easier yet is just use Fleetguard. It lasts for a few 100,000 mile in big class 8 truck engines so it's "fill for life" in small pickup truck diesels.