DEX COOL

[NC Bill]

Is it normal for the coolant level to reduce in the tank? I'm probably down an inch in 50 hours flying.

 

I see that AutoZone sells a 1 gal. 50/50 Pre-Diluted Dex-Cool antifreeze and coolant for use in GM cars and trucks. Should I just add this to bring the level back up to middle point?

[Roger Lee]

Just use distilled water to bring it back up. The coolant is either oozing out from under a hose which is usually one with a screw clamp or out of the 90 degree fitting on top of each cylinder. The high speed air moving through the cowl will blow it of these fittings or from around the hose. Look carefully and you will see a tiny bit of coolant at one of the hose edges or around one of the fitting insertion points. These fittings only screw in and use Loctite 648.

 

I do my best to stay away from Dex Cool since you have to be careful what gets mixed with it. Plain anti freeze doesn't have that issue.

[Jeremy MacGregor]

Bill the Dex-Cool is OK just make sure you use the premixed stuff. Rotax wants it mixed at 50:50 with distilled water if your using the concentrate. There are some manufactures (mostly Trikes and PPCs with open cowls) that recommend running 100% concentrate but Rotax doesn't like this because it will allow the coolant to stay to viscous and not cool as efficiently. If your down a bit I recommend to top off with coolant rather than water, if you ever have a option always favor on the side of more coolant than water. If you start getting up to the 65% water 35% coolant you can run into steam issues in the event you start to run excessively hot. Water can be used in a pinch just keep what I said in mind.