Coolant Refractometer Question.

[George7941]

I have a Robinair 75240 Refractometer

Coolant and Battery Refractometer | Robinair

www.robinair.com

I just checked the specific gravity of Diesel Exhaust Fluid in a fresh jug and it read 1.31. Previously I had checked 3 yr old DEF and it also read 1.31. Google says DEF should have 1.09 sg. I am using the battery acid scale to read sg, the coolant scales read in temperature degrees. I checked calibration using distilled water and it read 1.0.

Is there an issue with using the battery acid scale for DEF?

 

[SuperSalad]

Based on your result I would have to assume it isn't suitable for DEF. Solid urea has an SG of 1.34, so to get 1.31 would require an impossibly high percentage in solution.

Maybe it could be that there is a specific method for recalibrating for DEF, but I don't know that for sure.

 

[George7941]

Thanks. The refractometer works well for coolant. I just mixed up 50/50 Dexcool/distilled and it read -50C on the concentrate and -25C on the 50/50.
Looks like I will have to get a DEF refractometer

 

[George7941]

Just checked DEF with a couple of old coolant testers I have.

The floating balls tester had two balls out of four floating and the pivoting disc tester showed 1.11 sg, which is close to what the sg is supposed to be.

The OTC DEF refractometer is $193.74 CDN on Amazon.ca and there are cheap ones for under $25

Toolly DEF Refractometer for Measuring Diesel Exhaust Fluid Concentration of Diesel Engines, with ATC : Amazon.ca: Automotive

Toolly DEF Refractometer for Measuring Diesel Exhaust Fluid Concentration of Diesel Engines, with ATC : Amazon.ca: Automotive

www.amazon.ca

I will try out the cheap one.