Testing Fleet Charge antifreeze

[mjonesnh]

Today I decided to drain the green antifreeze from my Tc34da and replace with Fleet Charge. Owners manual recommends to replace every 12 months and I have owned the tractor for 3 years but it has less than 200 hours on it so I thought now would be a good time to do it.
Drained and flushed cooling system per owners manual and then mixed up a 50/50 mix of antifreeze and distilled water and filled system. After running the engine for around 20 minutes I shut engine off and let it set for a few minutes and then removed radiator cap. Inserted a Prestone tester that I have used for at least 5 years and checked the freeze protection level. It only tested -7 even though the label on jugs shows -34F for 50% mix just like the green Ethylene Glycol mix does.
My first thought was my tester was defective so I tested some 50/50 premixed Prestone antifreeze I have and it tested -32 to -34 F, just like it should. Decided I had made a mistake some where in the mix ratio,I drained one pint of antifreeze from radiator and added one pint of pure Fleet Charge and ran engine again to let mix circulate
This time it checked -20 F. This is only a 5.5 quart cooling system and I know the mix ratio has to be at least 50-60% and still checking lower than the recommended -34F. This is a Ethylene Glycol base antifreeze with SCA additives and I would think that any tester that can test the green antifreeze correctly would give a correct reading on this purple elixir.
Has anyone ever experienced these quirky test readings with Fleet Charge antifreeze and a regular green antifreeze tester. I might add this tester has a needle that floats up and down and not the kind with 5 little balls inside a plastic tube.

 

[SPYDERLK]

Possibly that antifreeze gives a low freeze point with a less dense solution than the regular stuff. That would "fool" a tester. If you still have the pint you drained try putting it in your freezer. A good freezer runs about 20 below F. If it doesnt freeze suspect that a std density gauge is inaccurate on the fleetcharge. You dont want to go to extreme antifreeze concentration because water is your best heat mover. The highest water% solution that gives both freeze and boil protection is your best coolant.
larry

 

[Jbrink64]

If Fleet charge is polypropylene glycol (ppg),and I think it is, an ethylene glycol (eg) tester won't work.

 

[mjonesnh]

If Fleet charge is polypropylene glycol (ppg),and I think it is, an ethylene glycol (eg) tester won't work.

Web site says Ethylene Glycol 90-95% by weight
Diethylene Glycol 0-5% by weight

 

[Jbrink64]

Web site says Ethylene Glycol 90-95% by weight
Diethylene Glycol 0-5% by weight

Yup, I just saw that. It also said to use a refractometer

 

[mjonesnh]

Thanks for pointing this out. I just looked and it says not to use automotive coolant test strips or hydrometers. Not sure what to do now. I may just dump the Fleet Charge and go with green Prestone. It had green Ethylene Glycol from factory fill and I know that my tester works on the green mix.

 

[SPYDERLK]

Thanks for pointing this out. I just looked and it says not to use automotive coolant test strips or hydrometers. Not sure what to do now. I may just dump the Fleet Charge and go with green Prestone. It had green Ethylene Glycol from factory fill and I know that my tester works on the green mix.

You could calibrate your tester for the fleetcharge. Really tho, once you are assured of the right concentration there is no need to test a sealed system. Just make sure any addition is the same concentration.
larry

 

[mjonesnh]

Update:

Drained Fleet Charge this morning (I really hated to do that,but) and rinsed twice with clear water. Left radiator and block drains open until both had quit dripping. Added approx 5.5 quarts of premixed Prestone and let tractor run till coolant circulated. Shut down engine and checked with hydrometer. -18F, What the "!!#&%&!". Can't be as this was 50/50 Prestone and tested it in the jug before filling radiator. I went and checked the F-150 as it has same antifreeze and it checked -34F.
I had to set down and drink an ice cold Coke and think about this for a while. Both times when the coolant was drained I rinsed with water and believe there is probably a quart of pure water left in block that does not make it to the block drain. The book states 5.5 quarts capacity and this seems about right for the amount that drains out and is replaced but believe 6.5 quarts total capacity is close to correct amount.
When antifreeze is added back there is probably about 1 quart of pure water left in block that dilutes the mix. I drained 16 ounces of coolant from radiator and added 16 ounces of undiluted Prestone back, ran tractor for 20 minutes and re-tested freeze point. -30F. YEAH!!
Starting out yesterday with Fleet Charge the first reading was -7F and then -20F after drained 1 pint and adding back 1 pint of undiluted. With the Prestone the fist reading was -18F and then -30F after the drain and refill. I do not believe the hydrometer is 100% compatible with the the Fleet Charge but it looks like it is probably only about 10 degrees less than with the green ethyl glycol mixture using almost exactly the same amounts of liquid and fill methods.
I am going to run this mixture for 12 months and then drain again next fall. Not sure if I will stick with Prestone or try Fleet Charge again as it has a good reputation when used in diesel engines.

A big THANK YOU to the members here who replied to this post trying figure what was going on with the chemistry ratio!

 

[jimmysisson]

Do you think that means that if you had no antifreeze, and you drained your tractor before freezing weather and left it "empty", that water would crack the block? That's a ****-poor design if true - you should be able to drain a cooling system and be pretty sure you got it all. Did you maybe miss a drain point - probably not. Hmmm...
Jim

 

[mjonesnh]

Do you think that means that if you had no antifreeze, and you drained your tractor before freezing weather and left it "empty", that water would crack the block? That's a ****-poor design if true - you should be able to drain a cooling system and be pretty sure you got it all. Did you maybe miss a drain point - probably not. Hmmm...
Jim

Only one drain on block that I can find, only one mentioned in manual. I am not saying my theory of some water being left in block after the drains have stopped dripping is the only possible explanation but, it's the one that made the most sense. The antifreeze tested very close to -34F in the jugs but only tested about -18F after being mixed in the radiator. This seems to indicate that the mixture was being diluted after it was poured into the coolant system.
If anyone else has opinions as to why the freeze point is changing after the coolant is added to radiator, please chime in. I would being interested in hearing other viewpoints.