Antifreeze Analysis

Was helping a friend with his boat yesterday and there was some concern about salt forming around his radiator cap. He replaced the failed heat exchanger a couple of years ago and this may have been residual from that.

I know that oil analysis companies such as Blackstone will do antifreeze analysis. Was wondering if there was a simpler test for salt in antifreeze (other than tasting it )? If there were a test strip that one could moisten from the overflow bottle at each oil change, that would seem like a very good PM test.

Ted

Greetings,
Mr. OC. I wonder if something like this would work? It may not due to the other chemicals in AF...


https://www.amazon.com/Industrial-Test-Systems-482341-Check/dp/B013UX7R7C

O C Diver said:

Was helping a friend with his boat yesterday and there was some concern about salt forming around his radiator cap. He replaced the failed heat exchanger a couple of years ago and this may have been residual from that.

I know that oil analysis companies such as Blackstone will do antifreeze analysis. Was wondering if there was a simpler test for salt in antifreeze (other than tasting it )? If there were a test strip that one could moisten from the overflow bottle at each oil change, that would seem like a very good PM test.

Ted

Click to expand...

A 50/50 mix of DI water and antifreeze when tested with an ohmmeter will have at least Mohms resistance across half an inch of distance. If you then add a 'pinch' of salt the ohmmeter will drop by 100 fold.

I doubt that what you are seeing is salt. Antifreeze causes the same white crystals to form at any leak.


Is the antifreeze level rising? If not then you don't have a sea water leak.



David

djmarchand said:

Is the antifreeze level rising? If not then you don't have a sea water leak.

Click to expand...

I have seen a heat exchanger leak where the pressure in the coolant loop went out through the heat exchanger without opening the radiator cap, and then sucked in salt water from the heat exchanger as the engine cooled down. Liquid level in the overall reservoir never changed.

Ted

RT Firefly said:

Greetings,
Mr. OC. I wonder if something like this would work? It may not due to the other chemicals in AF...


https://www.amazon.com/Industrial-Test-Systems-482341-Check/dp/B013UX7R7C

Click to expand...

Interesting idea. As you match the test strips to a color chart, wonder if the antifreeze would effect the color.

Ted

smitty477 said:

A 50/50 mix of DI water and antifreeze when tested with an ohmmeter will have at least Mohms resistance across half an inch of distance. If you then add a 'pinch' of salt the ohmmeter will drop by 100 fold.

Click to expand...

Sounds like it's worth a test.

Ted

It’s only good for so many years unless you use a coolant filter so it might just make sense to change it?

Xsbank said:

It’s only good for so many years unless you use a coolant filter so it might just make sense to change it?

Click to expand...

The intended purpose of the test was to detect early signs of a heat exchanger failing, not the life expectancy of antifreeze.

Tef

If the antifreeze ratio originally installed is known say 50/50, then any mixing of saltwater would raise the freeze point which would easily be seen with a standard antifreeze tester.

Ken

kchace said:

If the antifreeze ratio originally installed is known say 50/50, then any mixing of saltwater would raise the freeze point which would easily be seen with a standard antifreeze tester.

Ken

Click to expand...

Now that's a good observation! Im looking for something that would recognize a significantly smaller percentage of contamination.

Ted

Like David wrote are you sure this is salt? Evaporating antifreeze leaves a white powder looking like salt.

L

Lou_tribal said:

Like David wrote are you sure this is salt? Evaporating antifreeze leaves a white powder looking like salt.

L

Click to expand...

It's not my boat, and I'm not sure to what level of flushing the owner went to after replacing the heat exchanger.

My interest in a test to detect salt is based on my boat's PM protocol. If I could have a simple inexpensive test for sodium, I would likely do it with each engine oil change. As an example, if the test strip RTF linked would work, I would dip the antifreeze overflow bottle with each oil change.

Ted

Sodium is, I think, hard because I don't think it color-changes with any safe chemistry, if any chemistry at all.

Most sodium test kits are based upon conductivity. But, one needs a baseline for that, e.g. water, 50-50 ethylene glycol mix, etc. One would also need to test at about the same temperature, as there might be a big difference between a cold day, a hot day, and after the engine warms up. And, one would also likely need to be able to rule out accumulated contaminants, e.g. metal particles, etc.

Using a conductivity meter seems tough as a practical solution. Although, I guess if one tested frequently at a somewhat stable room temperature -- any fast change could be cause to take notice.

There are some meters that test for sodium ions, often used for food or medical applications. But, they aren't cheap -- I think they are all $300+. Things like this might work:

-- https://www.amazon.com/HORIBA-LAQUAtwin-3200456564-Model-Compact/dp/B00BSXGYVC

-- https://www.amazon.com/HORIBA-3200689159-Horiba-LAQUAtwin-Pocket/dp/B076F94K33

Cheers!
-Greg

I just looked at Wikipedia:
-- https://en.wikipedia.org/wiki/Seawater#Chemical_composition

And was reminded that NaCl is most of what sea salt is, and that there is actually more chloride in sea water than sodium.

Given this, and that significant levels of chloride shouldn't be in either the RO/DO water used in a coolant mix, or in the coolant, itself -- why not test for chloride?

I can't say that I've tried it, but chloride dip or titrate test kits should be pretty accurate, easy to use, and chemically selective. Maybe something like this:

-- https://www.amazon.com/Hach-2744940-Chloride-QuanTab-30-600/dp/B074WW6FSX

(I just ordered a set to see how it works if I take some 50-50 mix and add some salt water).

Cheers!
-Greg

gkesden said:

I just looked at Wikipedia:
-- https://en.wikipedia.org/wiki/Seawater#Chemical_composition

And was reminded that NaCl is most of what sea salt is, and that there is actually more chloride in sea water than sodium.

Given this, and that significant levels of chloride shouldn't be in either the RO/DO water used in a coolant mix, or in the coolant, itself -- why not test for chloride?

I can't say that I've tried it, but chloride dip or titrate test kits should be pretty accurate, easy to use, and chemically selective. Maybe something like this:

-- https://www.amazon.com/Hach-2744940-Chloride-QuanTab-30-600/dp/B074WW6FSX

(I just ordered a set to see how it works if I take some 50-50 mix and add some salt water).

Cheers!
-Greg

Click to expand...

I like it! Can't wait to see how well it works.

Ted

In theory, if I did the math right, this test kit should be able to detect about 1.2 tsp of salt water per gallon of coolant and saturate at about 25 tsps per gallon of coolant. There are others that cover other ranges, but this seemed like a good place to start.

This is good info. Waiting for the solution.

Greetings,

He has the solution he just has to analyze it. (Sorry, I worked with chemists for 35 years).

Agree with earlier comment, if there was enough salt in the coolant to begin forming salt crystals at the cap, I would think the coolant would be significantly diluted. As another said, simply test the coolant concentration.

Also, because the pressure in the closed cooling system is higher, when hot, than the seawater, you'd be expelling coolant when running, and drawing in seawater when cooling off, so definitely diluting the coolant.

For salt, or coolant residue, to form around the cap you'd also need a leak. Is the cap gasket defective?

A photo would help ID this.

(In Shanghai, homeward bound)

Antifreeze analysis

Cummins has an antifreeze test strip package that will tell the user whether the antifreeze falls within its specification. It does not give a Yes No answer since it measures several variables based on comparison with a color chart. So long as each variable falls within the range you are good to go. With 1800 hours, each variable is still midrange.

The salt may be molybdate... a mix of molybdenum and oxygen.

I rebuilt a Cummins in-line about 4 months ago and started to get water in my oil. I guessed it was from one of the liners because I was getting no oil in the water too and dropped the pan to find it thinking it was an o-ring damaged while installing the liners.

I plugged my keel cooler lines then pressurized the cooling system to 10 psi, put a mirror underneath the engine and waited... sure enough #2 liner was leaking. When I pulled the liner it had pitted soooo bad like I’ve never seen before, and in only four months!

Turned out to be from molybdate. Had to pull all 6 liners and replace them. Now I use Fleetguard DCA4 additive and check it with the test strips.

Was told that with Cummins and Caterpillar engines you have to watch that.

A TDS tester will provide a quick, direct and decisive answer whether there is sea water in the cooling system. A pressure tester will provide a direct and decisive answer whether there is a leak in the cooling system. A leak between coolant and sea water will always cause some net loss of coolant. Unless there are recent tests and records, glycol concentration isn't a decisive indicator, and even if so, it's not a direct indicator. If it was me, I'd use the pressure test in any case, by the time all is said & done, because it's predictive. But a TDS tester can be had cheap and may later be handy.

When servicing heat exchangers with removable tube bundles sealed with o-rings, tighten the end caps evenly, a bit each end back and forth. Don't trust the bosses in the end caps to insure alignment.

When servicing heat exchangers with removable tube bundles sealed with o-rings, tighten the end caps evenly, a bit each end back and forth. Don't trust the bosses in the end caps to insure alignment.

Click to expand...

When tightening end caps be very careful, the domed caps will crack very easily if over-tightened.