I got some test strips to test coolant and everything seems in order except nitrates. It looks like the nitrates are right around the 300 level. Can I just drain and refill the system or should I run the flush fluid through it? Why do we have to be concerned about the nitrate level, what purpose do they serve?
Do I have to be extra concerned about bleeding air out of the system while refilling?

 

You can add Motorcraft's Coolant Additive ONE time per flush interval to rejuvenate the Nitrites.

If you've already done that or are unsure of the history, I'd do a nice thorough flush since coolant systems seem to be the death of these trucks. You have to be meticulous and thorough. Drain, flush with hose, fill with Distilled, idle, drain, more Distilled, drain, new coolant/Distilled mix, idle, top off, drive a few miles, top off. Keep an eye on it for the next few dozen miles and top off as necessary.

Or... If you can find a vacuum filler, that would be ideal.

 

Forgot to add the use of Motorcrafts Coolant Flush additive wouldn't be a bad idea as well.

 

http://wpnet.us/flush.pdf

 

Thanks for the link. Would have been nice if you'd added a comment of some kind so users don't wonder if the link is a phishing scam or something.

Has anyone actually used this procedure?

In the document, it states...

"...commercial vehicles with auxiliary heaters..."?
What is this aux heater?

"remove the starter"?
WTF?

 

I think the aux heater they refer to would be something like the one in the back of the shuttle bus conversions you see used at hotels and airports. Just more total system volume I think.

I've not personally used the procedure, I've had my dealer do it after discussing it. With all that fluid to drain and dispose it's nice to let someone in a "real" shop deal with it.

The procedure for a contaminated system is even worse, they start with a run of Simple Green Pro HD solution, then like two more clear water runs to clear the cleaner, and then go into this VC-9 flush procedure to finish it off.

If you do it yourself, you can use the SEIC function to do the fast idle instead of needing a scan tool. Either way it's a lot of distilled or RO filtered water and a lot of coolant and flush solution to dispose of.

 

If you're still not done with the flush yet you can go on line to" power stroke help" and get his. It's on a you tube. it's not quite as involved as the one in the manual (he doesn't drain the block) but is very thorough. I did mine that way and added a sinister coolant filter a couple months back and everything seems to be OK. I tell ya, that last flush was clean enough to drink.

 

coolant mix is 50/50 with distilled in these, right?