Hello fellow IDI owners, I have a bit of a dilemma. I recently purchased an 84 F-250 with a 6.9 in it, and the owner had little to no information about how the engine has been maintained over the years (First diesel I have bought that wasn't family owned). Truck started decent in the cold and ran fine with no major issues evident. One thing that I forgot to do was check the coolant in the radiator prior to getting the engine to operating temps, so I just looked in the overflow reservoir. The coolant was a yellow-orange color, which to me said that it was an extended life coolant.

Today I remembered to look in the radiator before taking the truck out to work on fence, and the coolant looked green. This is the part that confused me as the coolant in the 7.3s we use on the farm all had the same color tint throughout the coolant system (I.E. yellow-orange in overflow and in radiator).

I was able to take some pictures to help illustrate what I am talking about.

Overflow:


Radiator:


Paranoia slowly crept into my mind so I went ahead and tested the coolant (As I should have prior to purchase) This is the sample's coloring and the results:




The strips showed that the Nitrate level was close to both the ideal and maintenance levels (Hard for me to decide which was closer). Due to these results, is it safe to presume that it is extended life coolant, or should I play it safe and flush the system and replace it with fleetguard so I know that the coolant is correct?

Any information is appreciated.

-Charlie

 

some one may have recently top off the reservoir, with extended life, or dex cool, IMO, that one should not use OAT type coolants in iDI engines, only fleet charge pre diluted pre charged with SCA's this coolant is purple in color and pre mixed with distilled water at 50/50 don't get me wrong, plane green coolant with the proper charge of SCA's will work ok, SCA's reduce the likely hood of tiny bubbles drilling hole's in your block. the new tech coolants may harm your old tech system, that said the old DT466 I drive at work has extended life coolant in it.ENJOY YOUR NEW TO YOU RIG

 

IMHO- If the guy did not know about the SCA requirements in the coolant, flush the system and start over. If you add SCA's to the coolant you absolutely need to know what you have because your SCA additive can cause problems, I think the tech said the coolant could become gelatin-like.

This line of thought will cost you about another $64 for Fleet Charge , plus $4 for distilled at the Food Lion, or $104 ($26 each) for Final Charge from NAPA, plus $4 for distilled.

Or, you can use low silicate extended and add the SCA, which I find to be at a disadvantage to the cost of Fleet Charge 100% at $16 in Advance

Peak Fleet Charge Antifreeze/Coolant (125 oz.) FCA0B3: Buy the right Antifreeze at Advance Auto Parts

 

i would flush the system and refill it with the proper green antifreeze and SCA additive, or an equivalent recommended coolant
it probably has green int he radiator, and someone topped off the overflow tank with the closest bottle they could get their hands on for to make the sale.

 

Thanks for the suggestions guys. I will pick up some Fleet Charge tomorrow and flush out the system this weekend. Glad I questioned it and didn't just leave it (Granted it is hard just to leave an engine as it is when you love tinkering with them).

-Charlie

 

X10 on flushing Charlie. The only things you can be sure of on these old trucks are the things you have done yourself. It will run you around 70 to 80 bucks to be sure, money well spent IMO. FWIW it is a good time to check hoses and clamps, t-stat all of the other things too. It will **** you off if you need to drain your system to change a hose or something in a month.

Good luck,

Mac.