- May 6, 2010
Just finished winterizing my engine with West Marine premium Marine antifreeze rated to -60. This is a polypropylene glycol antifreeze and when I finished I tested some of the exhaust discharge with the antifreeze in the bottle to make sure what was in the system was full strength. According to my refractometer both are rated to +10 degrees! I calibrated my refractometer and tested again with the same result. I then tested some green ethylene glycol anti-freeze I had on the boat and got the correct reading for that. I am familiar with using the refractometer and am aware there is a scale for both types of antifreeze and I am reading the correct scale. Not sure what explanation there may be but I think I will be re-doing the process with a different product.