"special"coolant tester (hydrometer) for low silicate formulas?

[chas3]

i found my old hydrometer and decided to give a try on the dexcool. it should be a 50/50 mix. it said that my freezing point was -5F. that didnt seem right so i mixed up some fresh from the bottle at 50/50 and its freezing point measured at -5F as well.

so, i guess this means the low silicate formulas cant be measured with a coolant tester (unless you get one that corrects for the different densities of the fluid)?

 

[tmorris1]

I had the same thing happen to me. The testers are supposed to work for all ethylene glycol antifreezes. I think they just test specific gravity. I had a cheap test that is pretty old so I chalked it up to that.

 

[Ray H]

Interesting - are you both certain that your Dex-Cool samples were concentrate and not pre-mix? Dex-Cool's available as either. In concentrate form, all automotive coolant/antifreeze products are overwhelmingly ethylene-glycol - around 93% to 94%, with about 4% water, and the rest, whatever corrosion inhibitor package the blender has selected.

[ July 08, 2004, 03:48 PM: Message edited by: Ray H ]

 

[chas3]

its not pre-mixed. i bought it about a year or two before that option became available. i checked some plain water and it seemed to be correct (pure water is a little off the scale).

i looked around in the local auto parts store but couldnt find a gage of any sort (let alone one that might have a scale for 'low-silicate' formulas).

 

[chas3]

sorry about the double post.

 

[tmorris1]

Mine wasn't premixed either. I had 50/50 Havoline Dex Cool and distilled water. Maybe we have the same tester.

 

[tmorris1]

Just a follow up on this. I bought the Prestone tester at Wal-Mart for $2.75 and it works just fine on both regular Prestone coolant and the Havoline DexCool. My cheaper tester said my DexCool was good to -10 and the Prestone tester said -37 or something.

 

[dagmando]

The same thing happened to me on my Honda coolant that I just recently changed. I went to get the oil changed and the guy said that my coolant was only good down to -5* but I just replaced the coolant with the pre-diluted factory Honda coolant that says -34*. When I got home I used my Prestone coolant tester with the dial and tested the pre-diluted coolant right from the jug and it also showed -5* and not the -34* the jug said. There must be a difference in testers.