I am in Mexico and I just had some radiator work done. I bought 2 gallons of Fleetguard concentrated coolant, pre-charged with 5 units of DCA and had the mechanic put it in. 2 weeks later I got some test strips and the following readings; Nitrate 4000 flush, freeze point -10, PH 8.

Do I have to flush the radiator or just dilute the antifreeze down?

 

Why are you wanting to dilute the antifreeze.

 

Because the nitrate reading is 4000 and the directions on the strip says flush. I am trying to avoid flushing the radiator and buying new coolant.

 

Ok I wasn't thinking and I am not sure on that. Did you use tap water or distilled water when you filled it.

 

I used reverse osmosis bottled drinking water. I couldn't find anything larger than a 12 oz bottle of distilled water for way too much money.

 

Dilute the coolant with water.
You may have to drain a little out of the radiator, but you can save it for later.

Were the test strips in date?

 

I hear you there. diluting your coolant may just work. I had my international in the shop once for a heating problem I couldn't figgure out that turned out to be the new batteries I had installed. Any way when I went to get the truck he said he had to dilute the antifreeze back to -34 to get it right. I was a little peod because I had to run -60 and that was more important than the ph or nitrate count.
I never saw the numbers so I'm not sure what he was getting right but he did dilute so if I was you I would dilute it and check it again seems like you should be able to go to -34 though maybe you just have too much additive. I always fill with coolant then test and add accordingly.

 

Living in the tropics, I don't need to worry about freezing. I am more concerned about proper protection from cavitation.

What problems could I encounter from running a higher concentration of coolant or additive? BTW, there is no expiration date on the container of test strips.

I will dilute it down this weekend and re-test.

Thanks for the advice and have a happy new years

 

I removed 2 gallons from my radiator and replaced it with water. I took it for a good long ride to get everything in the radiator to mix. The next morning I tested again and the nitrate reading was still 4000+ in the flush zone. It looks like the mechanico mixed my purple fleetguard antifreeze with some kind of green type.

I am just going to flush the radiator and start fresh. I have a pint of Motorcraft diesel cooling system additive. Do you guys recommend using the pre-charged Fleetguard antifreeze or just getting regular antifreeze and using the additive? What kind of % mixture with water should I use?

BTW the truck ran cooler with the coolant diluted, normally I run about 190 but on the last drive it stayed about 180 even with the A/C running. Strange?

 

Curious.... what's the purpose of DCA (Diesel Coolant Additive??)? I am mostly only familiar with gas powered passenger vehicles...... How bad would it be for a person to put regular green coolant in a diesel without the additive?

 

Just read another thread called "Coolant additive??????" (not certain how to post a link...) and it seems to have answerd my question! Looks like I'm going with regular green sruff (50/50 mix with distilled water) and a DCA (Napa of Motorcraft likely)

 

Down in Mexico I would think 50/50 would be plenty.

I run Fleetguard at about a 60/40 but it does get rather cold here.

Our daytime highs were in the single digits over the weekend.
You can guess where the lows were.