Video: How to Maintain Your Engine's Cooling System

Updated Dec 2, 2022

Proper maintenance for your construction equipment’s cooling system goes beyond checking the coolant freeze point a couple of times a year and topping off the tank.

In this episode of The Dirt, we hear from Shelly Eckert, business consultant for Chevron Lubricants, who explains how to properly test and maintain your cooling system – a system responsible for forty percent of engine failures - in this informative interview with host Bryan Furnace.

Cooling systems and coolants have changed a lot since the 90s. Today’s diesel engines have exhaust gas recirculation (EGR) systems to reduce the amount of nitrous oxide emitted and meet emissions standards. If your coolant becomes contaminated, it can change in viscosity and crack the EGR system.

So to learn more about how to maintain this often overlooked system and protect your engine from serious damage, check out the latest episode of The Dirt.

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In This Episode:

00:00 - Intro: How to Properly Maintain the Coolant System

00:34 - How to Properly Check the Freeze Point

03:01 - How Do Cold Temperatures Impact the Coolant System?

03:51 - The Difference Between Heavy-Duty Coolant and Extended Life Coolant

04:53 - Test Your Coolant With pH Strips

07:04 - Does Coolant Color Matter?

08:26 - Read the Fine Print

09:29 - How to Start a Proper Coolant Maintenance Program

10:58 - How the EGR Impacts Coolant

11:50 - Tips for Using pH Strips

12:12 - Final Thoughts and Overview


Bryan Furnace (00:00):

This Equipment World video is brought to you by Chevron Delo 600 ADF ultra-low ash diesel engine oil. It's time to kick some ash.


Hi everybody. Welcome back to Equipment World. You're watching The Dirt. I'm your host Bryan, and today we're here to talk about one of the most overlooked parts of your equipment when it comes to regular maintenance. We're talking about the coolant system. Why is it important to pay attention to coolant? And how to properly flush your coolant and what even coolant should you use? Here to talk with us today is Shelly Eckert with Chevron to give us some idea of how to properly maintain your coolant system. So my first question for you is, as a guy in the dirt industry, that just is the typical Joe Schmo. My idea of cooling maintenance is going out there with my little float bubble thing and dipping a little radiator fluid into it and making sure that it's beyond the right freezepoint. And we call it a day. As the expert in the industry, what am I lacking in my maintenance?

Shelly Eckert (00:56):

Well, the first thing is using the float bubble hydrometer. Over the years, I've gone out to shops and talked to the technicians and these are very common to be found in the shops. However, the problem is the second that oil gets up into here, the floating balls do not read right.

Bryan Furnace (01:12):

Got you.

Shelly Eckert (01:13):

So for example, I walked into a shop and I had, I don't know, four or five technicians and they all had these. "Well, this is what we use."

Bryan Furnace (01:20):

Industry standard.

Shelly Eckert (01:21):

Industry standard.

Bryan (01:22):


Shelly Eckert (01:23):

All of us took a freezepoint sample out of the cooling system and we were all different. One was brand new by the way. So I would always recommend that you use what we call a freezepoint refractometer. Looks just like what we use for a percent urea for diesel exhaust fluid. There are refractometers on the market that can do both percent urea and a freezepoint. They're very simple. They're used in all of the laboratories that test a freezepoint. All you have to do is lift the shield, put a couple of drops of coolant on it, drop the shield, make sure it's covered, bring it to a light source and read it.

Bryan Furnace (01:56):

And is reading it pretty simple?

Shelly Eckert (01:58):

It is. I mean there can be some complexity. Some of the refractometers can have ethylene glycol and propylene glycol and battery scale on it, which is most common in our industry for off-highway as well as on-highway, it is ethylene glycol.

Bryan Furnace (02:13):

Okay. So as long as you just ignore the other two, you're fine.

Shelly Eckert (02:15):

That's right. Ignore the other two.

Bryan Furnace (02:17):

Keep it simple. Now I will ask you this. In your float ball situation, was the brand new float ball reading correctly with your refractometer?

Shelly Eckert (02:24):

It was close.

Bryan Furnace (02:25):

So it was close, but still, you're not getting an accurate read?

Shelly Eckert (02:28):

You're not getting an accurate read.

Bryan Furnace (02:29):

Interesting. And yet that's the industry standard.

Shelly Eckert (02:31):

Well, it's not an industry standard, it's in default. But you can calibrate this with water as long as it is room temperature water, whether that is coming from a faucet, bottled water or even a stream. Water freezes at 32 degrees Fahrenheit. Throw it on here and there's a water line to make sure that it's reading appropriately.

Bryan Furnace (02:49):

Interesting. So that is very simple, very straightforward.

Shelly Eckert (02:51):

It is simple, and it's exactly what the lab uses. So you can get these from your lubricant provider or you can get them off of Amazon. But you want to get a nice good quality one too.

Bryan Furnace (03:01):

Well, my next question for you is, as I come into the winter months, what questions as a contractor, do I need to be asking about the coolant in my machine? I'm sure it goes above and beyond do we just need to top it off?

Shelly Eckert (03:11):

You need to start with checking that freezepoint and making sure that it is accurate. You also need to make sure that you're checking all of your hoses and your clamps and pressure checking the radiator to make sure the cooling system, to make sure it's maintaining its pressure. Because if it's not, everything you're doing and checking the freezepoint, it's a waste of time. If you change the radiator cap, drive it around, recheck the pressure because the radiator caps can be inexpensive and can fail right out of the box. We talk about winterization, right? As a key term, in my opinion, if you are doing a proper coolant maintenance program year-round, you really don't need to be winterizing. Now, if you're using a conventional heavy-duty coolant, you want to know, in my opinion, what the difference is between a heavy-duty conventional coolant and an extended-life coolant?

Bryan Furnace (03:56):

What's that?

Shelly Eckert (03:56):

Heavy duty conventional coolant, the additives go in and create like a blanket on the cooling system. And when you put a blanket on yourself, what happens?

Bryan Furnace (04:04):

You get warmer.

Shelly Eckert (04:05):

You get warmer. And when you do an extended life coolant, your organic acids are floating around and then they go in and protect where capitation starts. So you increase your heat transfer properties by about 10 or 12%.

Bryan Furnace (04:15):


Shelly Eckert (04:17):


Bryan Furnace (04:17):

So if I understand that correctly, running an extended life coolant will help your system run cooler?

Shelly Eckert (04:23):


Bryan Furnace (04:24):


Shelly Eckert (04:25):

Always a little bit more expensive because it's an extended-life coolant, but it is a longer life and less maintenance. All you really do is, you need to check your freezepoint and I highly recommend to check the organic acids that are in your coolant. You really need to start with understanding what is the coolant that you're using, whether that's a heavy-duty conventional coolant, an extended-life coolant, so you know what you're looking for. I like the freezepoint to start with because that's the number one physical property. And then I recommend using a pH test strip.

Bryan Furnace (04:54):

Why pH test strips out of curiosity?


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Why pH test strips out of curiosity?

Shelly Eckert (06:12):

This is on the same scale as a universal scale. You've got zero to 14, right?

Bryan Furnace (06:17):


Shelly Eckert (06:17):

With an extended life coolant it's typically eight to nine. When you're using a heavy-duty conventional coolant, it's usually somewhere higher, 12 maybe, if you've got too many nitrites in your coolant system. Because that's the other thing with an extended life coolant, you have either a nitrite free or a nitrite coolant and that's really OEM specific as to what you can and cannot use.

Bryan Furnace (06:39):

Oh, okay.

Shelly Eckert (06:40):

But more on the off-highway you're still going to see a variety of different coolants.

Bryan Furnace (06:43):

And don't mix them.

Shelly Eckert (06:44):

Don't mix them. You can mix up to 25% but because of the dye situation on the market, once you start mixing two different coolants, you can't really tell what is 25%.

Bryan Furnace (06:55):

Sure. You just get to the right level of brown and then you know you're roughly there.

Shelly Eckert (06:59):

No. Brown's really bad.

Bryan Furnace (07:01):

Oh sorry. Orangey green.

Shelly Eckert (07:04):

I have a comment about that. There is a rainbow of colors out there. And the dyes mean nothing, to tell you the truth.

Bryan Furnace (07:11):


Shelly Eckert (07:12):

Oh yeah.

Bryan Furnace (07:12):

So the whole adage of keep orange with orange and green with green doesn't actually mean anything?

Shelly Eckert (07:17):

Not really.

Bryan Furnace (07:18):

Got you.

Shelly Eckert (07:19):

In my opinion. So I run into a fluorescent green coolant that we weren't sure what it was, and so I ran it through the lab and had all of the testing done. Because that's what you really want to do, is send a sample into the lab because they have all of the instrumentation. When you're talking about test strips out in the field, that's a quick test. That's it.

Bryan Furnace (07:36):


Shelly Eckert (07:37):

And when in doubt send it to the lab. But I ran this to the lab and it came back as a Japanese hybrid coolant. So it was completely compatible with our nitrite-free coolant. I was talking to the engineer about this Japanese hybrid coolant and it was green and he said, "When did it get changed from conventional?" I said, "I'm not the engineer. That's you."

Bryan Furnace (07:56):

So now what you're telling me is we're the dumb dirt guys. We're not supposed to have to read labels and everything. We're supposed to use the colors and shapes game to figure this stuff out and now you're telling me the colors aren't going to work.

Shelly Eckert (08:06):

Now, I mean there's a guideline that's been put out with the Technology Maintenance Council that has changed over the years but it came out after the extended-life coolants were being put out there. And really, red is deemed as being an extended-life coolant. But I've seen red nitrite-free coolant, red long-life coolant. You have to read the fine prints that's in the documentation. I've seen a long-life coolant that's on the market that's marketed as being a million-mile coolant. And if you read the fine print it says you have to [inaudible 00:08:37] every hundred 150,000 miles. That's not extended-life coolant. I've also seen where you go out to the shops and they're on an extended life coolant and they're still using SCAs or supplemental coolant additives, whether that's liquid or pre-charged filters. And that's co-mingling coolants. So, for example, if you do have extended life coolant, you're trying to put in more additives, a lot of times you'll have an additive dropout and you'll start to see, no other way to say this, but it's white flocculate.

Bryan Furnace (09:04):

I was going to say flocculation. I nailed my chemistry term. That's awesome.

Shelly Eckert (09:10):

A good way to visualize it, is if you gargle with warm salt water and you put the salt into the water and you put too much salt in and it starts to accumulate at the bottom, that's white flocculant.

Bryan Furnace (09:19):

And really that's all of the stuff that's supposed to be protecting your coolant system. Dropping out of solution essentially.

Shelly Eckert (09:24):

That's exactly right. Because of the two additives. Are fighting and they're going to fall out and you'll lose protection.

Bryan Furnace (09:29):

So it sounds to me that if you're one of these contractors, like myself, who uses the color system and maybe a little back alley chemistry to mix your coolants, it sounds like really to get down to a proper maintenance program, it's almost better to do a full coolant flush and put in 100% of something you know what it is, so that you know exactly where your system stands.

Shelly Eckert (09:52):

I agree with that a hundred percent. I don't want to be wasteful, but if you just buy a new piece of equipment that's been leased out and it comes back and it's not the normal color coolant that you currently use, I would just change it out and start over.

Bryan Furnace (10:04):

Okay. And then going forward being all on the same page, you know exactly what's in your machine. Real maintenance from that point on forward, you're talking about doing your freeze check and then you recommended pH strips. Anything else that I need to really be concerned about other than kind of topping off the system and making sure my freezepoint's correct?

Shelly Eckert (10:22):

If you're using a conventional heavy-duty coolant, you want to make sure you have enough nitrite protection because those will deplete over time.

Bryan Furnace (10:29):

And how do I check that?

Shelly Eckert (10:30):

You can use a nitrite test strip that's on the market.

Bryan Furnace (10:33):

Oh, okay.

Shelly Eckert (10:33):

So you want to keep an eye on your cooling system. Right. Also keeping in mind that 40% of engine-related failures are coolant related.

Bryan Furnace (10:40):

Oh, wow.

Shelly Eckert (10:40):

So coolant is not something that should be overlooked.

Bryan Furnace (10:44):

And yet it is so often. It's kind of an afterthought.

Shelly Eckert (10:47):

It is. Because a lot of it was when extended life coolant came on the market, many of us were talking about how you can check it with your freezepoint once or twice of the year. And that was fine back in the nineties. But when the EGR came on the market and technology changed on these pieces of equipment.

Bryan Furnace (11:03):

That's not the case anymore. So how does the EGR affect the cooling system?

Shelly Eckert (11:06):

Well, this is funny. When I was at the lab, we were seeing contaminants hitting in the engine oil and then we were seeing contaminants hit the coolant where it was becoming acidic. We weren't putting two and two together at first until we started seeing feedback from our customers. And then we realized, holy smokes, if the coolant is over concentrated with glycol to the water mixture, the coolant will become more viscous, thicker. Goes up into the EGR and will crack the EGR and cause gas going into the coolant and cause the coolant to become acidic.

Bryan Furnace (11:36):


Shelly Eckert (11:36):

So if you have an EGR problem, you better darn well check the coolant.

Bryan Furnace (11:40):

Good to know.

Shelly Eckert (11:42):

Which you can also use the pH test strip. If it drops below seven, that's an indication that your coolant has become acidic. The one thing about the test strips, you want to make sure that they are color resistant because the dye can play around.

Bryan Furnace (11:56):

With your results. Yeah, that makes sense.

Shelly Eckert (11:58):

The newer the coolant, the more intense the dye is. It's not as accurate on brand new coolant, but it is accurate on in service coolants.

Bryan Furnace (12:05):

Well, this has been super informational. Thank you, Shelly. I learned a lot today.

Shelly Eckert (12:10):

You're welcome. Thanks, Bryan.

Bryan Furnace (12:12):

Well, thanks again for Shelly coming on the show to give us an idea of how to properly maintain your coolant system on your equipment. 40% of engine failures are due to cooling system issues. I had no idea. And yet it's a largely overlooked portion of your equipment. Hopefully, going forward, that's going to change due to the information Shelly was able to share with us today. So as always, I hope this has been helpful. You guys enjoy your holidays and we'll catch you on the next Dirt.