New to me 03 F350 7.3L stock truck. Coolant looks very clean, yellow/gold color but have no idea what's in it, good to -30*. What coolant strips are good to use and available in small quantities? I guess there is no way to tell what coolant is in the truck. What is the recommended readily available coolant?

 

Most switch to a elc coolant like semi trucks run. Like Rotella elc or peak final charge. But it requires a flush to do. But never have to test again or do any additives. Supposed to be good for million miles.

 

I second this. An ‘03 should have no trouble running ELC after a thorough flush. Easiest way to fill is to put in half the coolant system volume of ELC concentrate then top up with distilled water to achieve correct 50:50 mix ratio.

 

Napa sells the test strip kit for $15 but you get like 100 of them. I’ve never seen them sold in small quantities.

That sounds like the OEM ford gold coolant. I don’t know much about it as far as whether it comes SCA pre-charged for Diesel engines or not. Somebody else can chime in on that one or do some searching through older threads. On any newer truck Like yours it’s perfectly fine to flush it out and refill it with heavy duty engine coolant (usually red in color) which requires no maintenance as far as adding SCA periodically. Do a search for the “Gooch” coolant flush procedure if that is something you might be interested in.

 

Go to Walmart, buy DISTILLED WATER, do not use any other water in your system as other water contains impurities that will damage your system. Buy enough to do several full system flushes, full system flush means draining radiator and both sides of the block. 1 block drain valve is by oil filter, the other is by the starter, and of course, bottom of the radiator.

Drain system completely in en ironmental safe manner, lose all valves, fill with distilled water, run it for 15 - 30 minutes, drain again, you will still see debris and leftover coolant. Do this 4-6 times, it is a lengthy process but is cheap on the wallet and is worth the trouble.

Buy a good ELC coolant like Rotella ELC, I think that is what I have on my shelf. Bought extra to keep on-hand when I did mine.

point of order, before you finish the flushing, would be a good time to switch to the 203 deg thermostat if you are leaning towards doing so, and radiator hoses...

Once flushing is done, calculate the amount of ELC you need for the 50/50 mix and add ELC before anymore distilled water, top-off with distilled water and off you go.

It is not advisablebke to use the 50/50 premixed, use straight ELC.

Amazon had best price when I did mine 2 years ago.

Be sure you install the dual- alternator top hose so you do not have to drain coolant if you need a new drive belt too.

 

Once I drive it for a while I'll consider doing the flush and fill with distilled and ELC. For now I just want to test and see where I'm at with the good looking coolant that's in there. NAPA test strips are $40 for a bottle of 50 that I'm never going to use up. I see Fleetguard does sell 4 at a time for about $12. I think I'll call around and see if someone I know might have some.

 

Amazon is faster than your toes,
$12
for Fleetguard


if you would put your Location in your PROFILE,
maybe I would lend you a test strip.
you might be in china for all we know?

 

No problem on the profile, I know better. I'm in E TN. The $12 for Fleetguard was what I saw on Amazon.

 

Amazon is cheaper than me trying to mail you some strips, that is, if I can find the bottle again???

 

Okay I received the Fleetguard test strips and they have a good expiration date of May 2025. The sample in the hydrometer is to show what the coolant looks like. Using the test strips it shows adequate freeze protection but that's the only thing that makes any sense to me. open for suggestions at what I have going on. No idea what coolant is in the truck.

 

Based on what I see it looks like the OEM fill Ford Gold for 02-03 7.3.

I continue to run that since imo coolant is a consumable. ELC is better in every way, but it lasts longer than your waterpump/thermostat/hoses. Ends up on the ground anyway.

The Gold depletes SCAs but at much lower rate than green coolant. So it lasts longer. IIRC the yellow blop on your test strip is a good reading, but please compare to the bottle and let us know.

 

I agree I would just leave the gold stuff in there if the test strips say it's okay. Maybe at some point if you ever have to take the cooling system apart to do a water pump, that might be a good time to do a distilled water flush and and switch to the red stuff.

 

Here's the chart that came with the strips. The dark test spot at the bottom is for freeze point. I don't see where I get any reading for the others.
I used a strip on my diesel tractor's coolant which is plain green with WIX additive and the Molybdate panel turned pink.

 

Looks like you've either got nothing or too much on your Nitrite. It should say which one is which on the test strip container.

 

Middle pad is Molybdate, the one on the right is nitrite.