How to check antifreeze?

No worries, you will sleep better knowing you are protected.

Okay, I took a good light out to look at it again. I see the level in the reservoir is right up to the "cold full" mark. The hygrometer scale maxes out at -45C and the reading is just a little beyond that. Looks like it is working okay, just a little too much antifreeze. There is a large tube leading from the bottom of the reservoir to a tee in the big hose going from the bottom of the radiator to the engine - no plugging that up!

Sorry to have asked a dumb question!

Harvey51 wrote:
I did that and the hygrometer shows pure antifreeze, which can't be right. Last winter I put a Liter of pure antifreeze in that overflow reservoir and I figure it is still there - no mixing with the radiator. I see problems with those little tubes plugging up are common.

When you added last year, did you suspect you were just low or that you needed more strength. You apparently passed the strength required last year.

On some vehicles, there is not an easy way to add directly to the radiator. When the system in my Chevy works properly, the engine heat expands the antifreeze mix sufficiently to push it into the overflow/expansion tank. When it cools, the vaccuming action returns that antifreeze (now mixed with anything you added) back to the radiator.

I did that and the hygrometer shows pure antifreeze, which can't be right. Last winter I put a Liter of pure antifreeze in that overflow reservoir and I figure it is still there - no mixing with the radiator. I see problems with those little tubes plugging up are common.

The "Expansion" tank is under pressure on this model. The black cap on that tank is your "radiator pressure cap". Just take the cap off when the system is cold, pull out some coolant and test it. What's so hard about that?

After a few warm /cold cycles coolant in the overflow / expansion tank will be the same mixture as is in the engine. No need to measure coolant in the rad. (thats cdn speak) to you in lower no. america.
A hygrometer which measures specific gravity of coolant fluids, related to freeze point is the tool.
As long as you have used propylene glycol antifreeze with at least a 50% ratio to water, you should be fine.

I have the density tester. I checked the coolant in the overflow tank with it and the density is off the scale - looks like it is the pure antifreeze I put in there a year ago. I suspect the coolant in the overflow is not mixing with the contents of the radiator.

Anyone know if there is a convenient way to drain a cup full out of the rad?
It is -20C here so unpleasant to be lying in the snow under the engine looking for it.

The overflow/expansion tank is connected so the added coolant will make its way into the engine over time and be diluted same as the rest. Keep the level between the low and full marks and you should be fine. Although if you are adding coolant very much you should start suspecting a leak.

You can buy a coolant tester at a good parts house. You may need to extend the dip tube to get a sample from the fill tank. Of course if you just added 100% coolant and have not driven you will be getting a false reading.

I've found that a little flashlight held up against the coolant tanks and moved up and down is a quick way of telling where the level is. The entire tank seems to turn from white to green (or whatever color the coolant in question is) when you get below the level of the liquid.

Harvey51- I would have expected that the Ford chassis is not that much different than our Chevy. The radiator has a plastic see-through overflow tank, but it really is nothing more than an expansion chamber. It is marked on the side "low" and "hot". It functions like the upper tank on a 1960's radiator. We can check the strength of the antifreeze in that tank.

As the fluid in the radiator heats up to operating temperature it overflows into the expansion chamber. As the engine cools, the fluid is returned to the radiator by siphoning action.