TECH TALK with David VanDenburgh
Are Your Systems Protected?
For those of us in northern climes, particularly in the Great Lakes region, winter is just around the corner, which means it’s time (or past time) to haul and prepare for winter storage. If you’re a new boater, you’re likely getting a crash course in travel lifts, indoor vs outdoor storage, off-season maintenance and, of course, winterizing, all of which can be a bit intimidating, especially if you’ve decided to perform some (or all) of the winterizing yourself. If you’re a seasoned boater, this time of year probably comes with a lot less anxiety and uncertainty, and yet there may be some things you didn’t know.
I have performed my own winterizing in Michigan for nearly 20 years according to three basic rules: 1) -50 (pink) antifreeze in “non-critical” applications - e.g., pressure water system, heads and holding tanks, water heaters, washdown pumps and bilge pumps, etc. 2) -100 (blue) antifreeze in critical applications - e.g., engine raw water cooling and exhaust systems, generator raw water cooling systems, sea strainers and intakes; 3) verify all protection levels with a refractometer, not simply by eye or color or quantity of antifreeze added to a system.
Over the years, I’ve read a few discussions about which antifreeze is necessary, best winterization practices, and what -50 and -100 protection really means. And, as much as I hate to say it, I’ve even witnessed professional winterizations performed either carelessly or incorrectly.
As someone who values information and likes to learn things firsthand, I decided there was an easy way to test my assumptions and observe exactly how the two protection levels performed.
Simply, I mixed separate batches of -50 and -100 antifreeze at various dilutions/concentrations and then left the samples outside during winter for observation and data collection. (YouTube video link below).
Although my test was far from scientific, it provided a good illustration of why the three basic rules I established for myself are so important.
- Concentration matters. Neither -50 nor -100 antifreeze should be diluted. Diluted antifreeze (unlike the coolant that’s in your closed cooling system) does NOT offer full protection; full protection is only at 100% concentration.
- Judging concentration solely by eye or antifreeze color is not a reliable way to determine protection level.
- A refractometer suitable for propylene glycol is the only reliable way to assess protection levels.
Simply running a gallon or two through an engine or other system does not guarantee adequate protection. I’ve heard well-meaning but uninformed boaters advise yard neighbors to “run the engine till antifreeze comes out of the exhaust and then shut it down”. A quick check of the discharge with a refractometer would likely reveal only minimal protection, perhaps only to 25 degrees (or worse).
-50 antifreeze used in critical applications provides less margin for error.
Boats are expensive. Antifreeze, a refractometer, and a little care are cheap insurance against expensive and unwanted repairs.
View the Antifreeze Protection video: https://youtu.be/OW8IhClld8w