Anti-Freeze Strength

[KEH]

For those of you that get well below freezing...
2018 R21 with the Raptor engine delivered to Canada.
I winterize my own boat.
Perhaps I’m more thorough than some, but I decided to test my coolant strength despite what the attached tag showed.
Good thing I did because as you can see the test numbers don’t match up with the tag.
Yes, I calibrated the refractometer and tested it twice.
Dealer also wanted to test a sample , so I brought it in and they were pretty surprised to get the same results as I did.
They tested a few other boats in stock that were delivered around the same time as ours and they were all good.
They still have one boat left to test that was delivered at the same time as ours.
Dealer is going to do a coolant flush on our boat.
Perhaps it’s just an isolated case but thought I would put it out there for anyone that took delivery in 2018.

Cheers

[bsreid]

Maybe your problem is the cold winter not the antifreeze, lol. But that’s definitely interesting how it’s different.

[chpthril]

Coolant does age. Temp cycles and hours between feb and sept could make a difference that no fault of an individual.

[KEH]

Coolant does age. Temp cycles and hours between feb and sept could make a difference that no fault of an individual.

It’s got just under 50 hours.
If coolant “ages” that fast (which I don’t believe it does) then there should be a lot of cold weather boat owners doing the same check that I’ve done.

[chpthril]

At what interval does indmar recommend testing the coolant?

[KEH]

At what interval does indmar recommend testing the coolant?

Check every 300 hours or annually
Change every 2 years

[talltigeguy]

Does antifreeze expand the same as water when it freezes?

Interestingly, a brief internet search only found forums like this. Some RV guys are pretty sure it does not expand, so it may not hurt anything even if it does freeze.

[KEH]

Does antifreeze expand the same as water when it freezes?

Interestingly, a brief internet search only found forums like this. Some RV guys are pretty sure it does not expand, so it may not hurt anything even if it does freeze.

Great question.

This is right out of the Indmar manual:

Your Indmar engine is equipped with a cooling system
that uses a 50/50 propylene glycol antifreeze and water
mixture in the engine block and raw water in the heat
exchanger and exhaust system. If the boat is kept in
an area where the temperature falls below the freezing
point of water (32°F or 0°C), the cooling system must be
winterized to prevent freeze damage to the engine.
The protection level of the antifreeze must be tested
using a refractometer type antifreeze tester that is
designed to test propylene glycol antifreeze. These
testers are available at automobile parts stores and can
also be found on many websites that sell automotive
related tools and equipment. Follow the instructions that
come with the tester and make sure the antifreeze in the
engine will protect to lower than the lowest temperature
that your part of the world experiences.

The way it is worded makes it sound like you could do damage if your temps get lower than the rating for your propylene glycol.

[chpthril]

The way it is worded makes it sound like you could do damage if your temps get lower than the rating for your propylene glycol.

Very reason for the tool and recommendation to test it. Freeze CAN occur if the temps fall below the rated freeze point of the AF/H2O ratio.

[KEH]

https://www.shoptalkbyindmar.com/service-tips

Reference the above link, it looks like:
At any ratio of 35:65 (35%) or higher, propylene glycol provides additional protection to lower than -50°F (-46°C). This protection level is referred to as the burst point. The burst point is the point where the crystals in the coolant are able to expand and cause damage to the cooling system.

So turns out my ratio should be OK for burst point at -10F, but I'm still going to let my dealer do the flush to bring it up to -30

[talltigeguy]

https://www.shoptalkbyindmar.com/service-tips

Reference the above link, it looks like:
At any ratio of 35:65 (35%) or higher, propylene glycol provides additional protection to lower than -50°F (-46°C). This protection level is referred to as the burst point. The burst point is the point where the crystals in the coolant are able to expand and cause damage to the cooling system.

So turns out my ratio should be OK for burst point at -10F, but I'm still going to let my dealer do the flush to bring it up to -30

Good find. That sounds a lot more like what I was expecting. Interesting that the owner's manual seems to be so cautious, compared to the basic scientific facts.