Testing Engine Coolant

[exMaggieDrum]

What can you all tell me about the best way to test the engine freshwater coolant for my Perkins 4-108? I just found some mechanic notes from the last engine rebuild and the mechanic suggested that the coolant be checked with pH strips. I am sure this depends on the type of coolant/antifreeze and that the test strip may not actually test for pH.

Also any recommendations on the brand/type of coolant to mix with my freshwater would be cool.

I want to baby my old engine and I know that the coolant can be critical.

Thanks to all you gearheads who can help.

[colemj]

Instead of testing it, just go ahead and replace it. Coolant is very cheap and available everywhere.

Drain the old coolant and add 50/50 of any brand name "universal" coolant and you will be fine.

Mark

[robert sailor]

It is tested in a similar method as you use when testing a battery. You have a special hydrometer set for engine coolant
You simply draw coolant from your engine and read the results. These testers are cheap and available at most auto parts stores.

[colemj]

While this will test if the coolant is sufficient enough for antifreeze/overheating (glycol level), it doesn't tell anything about the anti-corrosion properties - which are the most important part, assuming one is somewhere in the % glycol ballpark.

If the coolant hasn't been changed for a while, it is better the OP simply change it rather than worry about testing it.

They do also make test strips for % glycol.

Mark

[thinwater]

I've been in the coolant business most of my life (1 formulation patent that was in use for 15 years, and have produced many millions of gallons).

Testing for glycol is simple. every sailor should have a pocket refractometer, since it is good for battery SOC too and is very accurate. Also good for making certain that winterizing glycol is sufficient (you never know how much water was in the system--test what comes out).

pH will tell you nothing unless you know the formulation. Additionally, the range of acceptable is quite wide.

The MOST important spec is chloride, from seawater contamination. No field test accurate enough in the low range. This is the reason Yanmar recomends annual changes--the seawater risk.

There are test kits available for $15-25 that give meaningful information, but unless you know the chemistry well and use them regularly, they are only confusing.

Short answer; change the AF annually and don't bother testing. The only reason I might consider testing is if the AF looks really strange and you want to know what is wrong... but will you know the cause from the data? Not unless you are in the industry. A lot of rust generally means air is getting in the coolant, generally from an exhaust gasket or water pump. Pitting in the heat exchanger is generally a salt problem.

[exMaggieDrum]

While I do care if the antifreeze part of the coolant mixture is adequate so the engine doesn't freeze up in the winter, I am more concerned about the other protective properties in a diesel engine. My Perkins is not what you would call a high tech performance engine but I have been told that the other qualities matter to any diesel.

I think one of the issues is cavitation at the cylinder walls and also just corrosion of the entire system. But I don't know if it is worth it to fuss with (preposition proudly put at the end of the sentence).

Mark - just changing it annually would work too. But it's a chore and I have to dispose of the old stuff as it can't go overboard or down a drain so it would be nice to not have to do that every year.

And there are test strips for glycol but also for other properties, which is what I am trying to sort out.

I know many diesels run extended life coolants. And some of those require an additive every three years or so since something in them is "used up".

Thanks for the feedback so far. It is appreciated.