Which coolant should I use?

[tinfoil_hat]

I went around and around on this a few years ago.
After seeing what old Dex can do I swore I would find a better product. After hours spent reading different articles and forum posts I converted all of our vehicles to Zerex G05. But see most of these vehicles leak here or there and need to be topped off. I couldn't find the G05 anywhere reliably. Wife and kids would buy the wrong stuff, etc. Eventually I said to hell with it and went back to what the manuals specify for each vehicle.
For the Suburban, I buy the full strength Oreilly Dexcool knockoff, mix it 50/50 at home. The key is to flush it yearly. As mentioned above, make sure you pull the knock sensor and the block drain on the other side. The first time I did this nothing came out but rusty dust.

 

[Schurkey]

With conventional antifreeze, why not TEST the stuff before flushing? While you have the radiator cap off, check for "radiator voltage" also.

Test strips show freeze protection, and acid content. If the coolant tests good...no reason to dump it.
www.amazon.com/Phoenix-Systems-8001-B-Determine-Automotive/dp/B01CNHJ4QI/ref=sr_1_7?crid=JNODP4HGKQ2A

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Voltage in the coolant is BAD NEWS. Two possibilities: 1. The ground cables need cleaning, and 2. the coolant is acidic and acting as an electrolyte.

You guys seem really paranoid about coolant degradation. I use normal old-fashioned green for 4+ years with zero issues. Extended-life coolant maybe 10 years.

My fleet is slowly--very slowly--getting switched over to Peak Global Lifetime concentrate, which I cut with distilled water.

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I don't understand Evans Waterless coolant. There's multiple formulations, the big secret is propylene glycol, and you can get propylene glycol antifreeze for about 1/5 the cost of Evans brand.

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[454cid]

With conventional antifreeze, why not TEST the stuff before flushing? While you have the radiator cap off, check for "radiator voltage" also.

I've checked for voltage and freeze protection, but not acidity. I will have to do that. Thanks for mentioning it.

 

[classman]

As coolant ages, it becomes acidic. If the coolant becomes too acidic, the cooling system component can be damaged. A voltmeter can be used to determine the acidity of coolant. Attach one multimeter lead to a metal that is in contact with coolant, such as filler neck, radiator tank, or cylinder head or block. Suspend the other multimeter lead in the coolant. If the multimeter reading exceeds 0.5 volts, the coolant has become too acidic. It should be drained and replaced. A stray voltage of 0.5 volts or more can affect sensors and control modules.

 

[454cid]

As coolant ages, it becomes acidic. If the coolant becomes too acidic, the cooling system component can be damaged. A voltmeter can be used to determine the acidity of coolant. Attach one multimeter lead to a metal that is in contact with coolant, such as filler neck, radiator tank, or cylinder head or block. Suspend the other multimeter lead in the coolant. If the multimeter reading exceeds 0.5 volts, the coolant has become too acidic. It should be drained and replaced. A stray voltage of 0.5 volts or more can affect sensors and control modules.

Most of our radiator tanks are made of plastic, but they're pretty well isolated from power anyway unless they are grounding through transmission cooler lines. I'd think it would be a very poor test to use the radiator as a second contact point.

 

[Schurkey]

With conventional antifreeze, why not TEST the stuff before flushing? While you have the radiator cap off, check for "radiator voltage" also.

Test strips show freeze protection, and acid content. If the coolant tests good...no reason to dump it.
www.amazon.com/Phoenix-Systems-8001-B-Determine-Automotive/dp/B01CNHJ4QI/ref=sr_1_7?crid=JNODP4HGKQ2A

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The test strips I have are ancient, and only work with conventional coolant. In fact, I think they've "expired" since I bought them.

The test strips linked-to, work with "any" coolant. So even with more-modern coolant, you can test for freeze protection and acid content.

Just wanted to correct my first sentence in the previous post.

Voltage in the coolant is BAD NEWS. Two possibilities: 1. The ground cables need cleaning, and 2. the coolant is acidic and acting as an electrolyte.

Most of our radiator tanks are made of plastic, but they're pretty well isolated from power anyway unless they are grounding through transmission cooler lines.

True for voltage due to bad grounds. Not true for voltage due to electrolysis, where the coolant itself has become the electrolyte in a "battery" composed of the different metals in your cooling system. The most-active metal (aluminum, zinc, magnesium) is the metal that will corrode the worst/fastest.

There are still zinc or magnesium anodes (or is it a cathode) you can poke into the cooling system to be "sacrificial". They screw into the (radiator, usually) in place of a draincock or other threaded opening. Mostly they're sold for water heaters and marine use, but if you look hard enough you'll find smaller ones for automotive radiators.

Yes, connect the voltmeter, dangle the lead in the coolant as described in Post 24. Less indicated voltage is better. (I would not be comfortable with half-a-volt.)

 

[454cid]

True for voltage due to bad grounds. Not true for voltage due to electrolysis, where the coolant itself has become the electrolyte in a "battery" composed of the different metals in your cooling system. The most-active metal (aluminum, zinc, magnesium) is the metal that will corrode the worst/fastest.

Ok, I was thinking the battery would still play a role. It sounds like the radiator itself becomes a make-shift battery. I guess in the case of plastic tanks, the core itself would need to be used. I will have to do this, since I've only been checking for bad grounds.

Thank you for the correction, and the further explanation.