Suitable coolant / Corrosion inhibitor.

[rob love]

An ohmeter to test PH is a new one on me, but I do believe the PH level and the continuity may be related.

If you google antifreeze PH test, you will find a lot more about the subject. One article mentions that automotive parts stores will sell test strips. Apparently, water is fairly PH neutral at around 7, and AF is around 10. Mixed 50/50, the PH goes to about 8.5. The PH adjustment that the articles mention is to bring it back to around 10. Seems to me with the heavy trucks, we changed the coolant filters, and could adjust the PH through using a differently rated filter.

I have always preferred the common green A/F. My wifes car (an Oldsmobile) requires the yellow stuff called dexcool, and that is touted as long life. It is also relatively expensive.

I would venture to guess that you guys from the Southern Hemisphere don't have a lot of antifreeze experience. Up here it is mandatory.....a night outside with just water and you will crack your engine block.

[cletrac (RIP)]

I've had motors with the same antifreeze in them for 40 years and there were no problems.
Don't mix colours on antifreeze. Use the proper type with aluminum heads.
Heavy duty diesel antifreeze won't score cylinders if it gets past the O-rings on the sleeves.

[RichardT10829]

I didn't run anti freeze during summer months, but rather distilled water and water wetter which has inhibitors in. the block was pristine clean ! it also ran cooler too

[Ken Smith]

Good day,
I use Caterpillar coolant in all my vehicles petrol and diesel, it is reasonably priced and does a good job keeping the coolant systems rust free. They also have an extender that you can use to recharge the coolant.
We use it in our Cat engined machines and trucks at work that are left out in all weathers, the only problem we have is in cold weather when the coolant pipes shrink and then there is a small weep at the hose. We either tighten the clamps a bit or when the engine warms up and the pipes expand the weep stops.
Ken

[Lynn Eades]

The first thing I found on the net:

If you think the only job of antifreeze (coolant) is to cool the engine during the summer and prevent freeze-up during the winter, read on. Coolant also plays an important role in preventing corrosion caused by electrolysis. Electrolysis occurs when two dissimilar metals start swapping electrons, causing the metals to corrode. Since an engine has aluminum, copper, cast iron, steel and magnesium alloys, electrolysis will slowly eat away at its innards.

Coolant has additives to prevent all of that electron swapping. But, as coolant ages, the additives are depleted and can’t do the job anymore. In fact, worn coolant becomes a pretty darn good electrical conductor, accelerating internal electrolysis. The good news is that it’s pretty easy to check the conductivity of your coolant with a digital multimeter. If the conductivity is high, it’s time for a coolant flush and fill. Here’s a quick way to check it.

Begin with a cold engine. Remove the radiator cap and start the engine. Set your digital multimeter to DC volts at 20 volts or less. When the engine reaches operating temperature, insert the positive probe directly into the coolant. Rev the engine to 2,000 rpm and place the negative probe on the negative battery terminal. If the digital meter reads .4 volts or less, your coolant is in good condition. If it’s greater than .4 volts, the electrolysis additives are exhausted, and you may be in the market for a new radiator, a water pump or a heater core in the future. All of those are far more expensive than a simple coolant change.

[Lynn Eades]

A different angle:

By Ralph Kalal

You knew you had to worry about the freeze protection offered by antifreeze. But, do you need to worry about your coolant’s pH, as well?

Many mechanics claim that testing the pH level of antifreeze is an effective way of determining its condition. Some professional repair shops offer additives ostensibly intended to insure a proper pH in your antifreeze.

Here’s the pitch: water has a pH of 7.0 and antifreeze has a pH of 10.5, so a 50-50 mix has a pH of 8.75, and that’s too acidic to protect the cooling system, so the pH must be modified to something around 10 to protect the dissimilar metals in the modern cooling system. And, further, antifreeze must be frequently replaced to ensure proper pH.

The pH value is a way of expressing the relative acidity of coolant. Acidity does cause corrosion. There are even reported instances of old coolant becoming so acidic that it turns the entire engine into, in effect, a battery, affecting electronic engine controls.

Look closely, though, and you’ll notice that the typical pitch for replacing antifreeze (because it has the wrong pH) simply equates the pH of water to the pH of conventional green ethylene glycol antifreeze at a 50-50 mix, and then claims that the resulting number is too acidic.

That comparison ignores the corrosion resistant formulations built into modern antifreezes, especially the Dex-Cool and G-05 long-life formulations. These antifreezes are designed to have a lower pH than conventional ethylene glycol antifreezes; 8.3 compared with 10.
Test strips that can be dipped into the antifreeze to determine the pH level are available at auto parts stores, if you want to check your antifreeze’s pH level.

With but one exception, it is not a good idea to supplement Dex-Cool or G-05 with additives, even those claiming to be compatible with those products. The corrosion-resistant capabilities of OAT antifreezes are the result of its organic chemical structure, the same chemical structure that delivers its freeze protection.

The sole exception is when the manufacturer says to put something else into the antifreeze solution, as specified in either the owner’s manual or the factory shop manual, in order to address a specific coolant concern. Cadillac, for example, specified the addition of “coolant tablets” to antifreeze in pre-2000 Northstar engines to eliminate a porosity problem with the aluminum engine block casting that could lead to coolant leaks.

Last, but certainly not least, is whether the antifreeze in your car offers adequate protection against freezing. You can test this.

There was a picture here, of an antifreeze hydrometer, which doesn't come through with the "copy and paste"

Test it with a “coolant hydrometer” available at any auto parts store. This inexpensive device measures the specific gravity of the coolant. It does not, however, tell you anything of the corrosion protection capabilities remaining in the coolant. Simply insert the tip of the hydrometer into the antifreeze and pull some into the chamber, enough that the float lifts free. The reading tells you the freeze protection.

[Lynn Eades]

And then on You tube:

https://www.youtube.com/watch?v=mBXZtfzHhig