With my device it was reading between minus 30 & minus 34. I then removed about 5 pints from the reservoir & replaced that volume with an equal volume......now reads after circulation....minus 37 F. Still have a little over a half gallon. After I run it some more with the heater on....I'll replace what's in the reservoir again. At least most of what's in the system is new with good anti-corrosion properties. Everything in the system is crystal clear.....just tinted a little blue. Kind of irritating.....suppose I should have been clear with the shop that I wanted EVERYTHING flushed and replaced. Compared with prices at the dealership over the years this shop has saved me thousands of $.