Are you searching for the best antifreeze/coolant for your Cummins diesel engine? Then sit back and relax as you’ve come to the right place.
In our article, you’ll learn about the best overall antifreeze, types & specifications, manufacturer’s pick as well as user’s choice from trusted websites, and a few other top-quality alternative coolants.
So without further ado, let’s find out the best antifreeze for Cummins diesel alongside some other essentials.
Click here to skip to our recommended pick!
- Long service life
- Approved by the manufacturers
- Prevents engine ailments
- 50-50 premixed for modern diesel engines
- Extended life formula
- No additional mixing necessary
- Specifically recommended by Cummins
- Prediluted, no additive required initially
- Long service intervals
Our Overall #1 Rated Pick
Valvoline Zerex Heavy Duty Extended Life Coolant
- Cummins 14603 approved
- 3yrs/ 7000 hours/ 300,000 miles per filling
- Denatonium Benzoate bittering agent
We highly recommend the Valvoline Zerex Heavy Duty coolant as the best overall antifreeze liquid for your Cummins diesel engine. It is Cummins 14603 approved that meets the ASTM D6210 specs as well.
This antifreeze is designed to prolong your engine’s lifespan. Upon the initial filling, it’ll be in service for 3 yrs/ 7000 hours/ 300,000 miles. Whichever comes first.
The coolant is rich with specially charged inhibitors that protect your Cummins diesel engine from liner pitting as well as hard water scale deposits. Ensures longer engine life and smoother performance.
Besides, it contains virgin ethylene glycol that prevents from freeze and boil-over. And the hybrid corrosion inhibitor package of organic acid protects your cylinder liners from cavitation, rust, and corrosion.
Antifreeze for Cummins Diesel – Manufacturer’s Recommendation
The Cummins manufacturers highly recommend the ‘Fleetguard’ coolant as the most stable and effective coolant system for this diesel engine.
According to them, the Fleetguard coolant offers superior protection as well as easy maintenance for the Cummins engine. It protects your engine from freeze and boil-over. Also, it keeps persistent engine problems like scales, corrosion, liner pitting, & voids at bay.
Also, this coolant meets the working standards and performance specs of many different OEMs on the market. Recommended antifreeze for Cummins diesel as well.
Once you fill up your engine with a proper coolant, you should check its quality at regular intervals. Add additives or chemically charged filters if necessary.
Type of Antifreeze: Manufacturers recommend HOAT type antifreeze for the best results. Precisely, a coolant that meets the “CES 14603” specs. This guide will bring you better clarity.
Capacity: When you flush out your old coolant, you may get around 4-5 gallons. But a Cummins engine can hold 6 gallons of coolant. So you should consider the amount while buying a new coolant. The Yellow HOAT coolants typically last longer than other coolants. So try to use those for the best use of your money.
It’s also recommended that you change the T-stat along with your coolant as well.
Antifreeze for Cummins Diesel – Users’ Pick
Let’s take a look at what the users prefer. Manufacturers’ recommendation is one thing but in practical situations, the proper coolant type depends on many variables. User comfort and experience play a crucial role in this as well. You could check out this forum as well as this one and see it for yourself.
Considering the users’ recommendations on several forums, the “HOAT” type coolant is preferred by most Cummins diesel owners. Precisely, they recommend they recommend the “Zerex G-05”.
About the Product
The Valvoline ZEREX G-05 is a Hybrid Organic Acid Technology (HOAT) type coolant. It has an automaker approved original chemical blend is suitable for Cummins, Ford, Chrysler, and Mercedes-Benz diesel engines.
The HOAT formula combines conventional and organic acid-based chemistry. Provides the ultimate protection against rust, corrosion, liner pitting, voids, etc.
Besides, the ZEREX G-05 antifreeze uses the highest quality virgin ethylene glycol, protecting from freeze and boil-over. Also, it has a hybrid organic acid corrosion inhibitor package.
Important Note
Check to see if the Coolant matches your manufacturer’s recommendation. Assess the market a little before purchasing a product. Most of the users’ preferred buying from the local NAPA. As many distributors tend to mark-up the price. Besides, Coolants can be costly. So look for a low-maintenance one.
Best Antifreeze for Cummins Diesel
Now that you know exactly what to look for and how it all affects your Cummins diesel engine, it’s time to look at our top recommendations. You may be short on time, so we’ve cut-short your work and screened out some of the best products from the market. Take a look.
The top best product [hide]
Valvoline Zerex Heavy Duty Extended Life Coolant
Works as 6.7 Cummins antifreeze and 5.9 Cummins coolant type. The coolant is rich with specially charged inhibitors that protect your Cummins diesel engine from liner pitting as well as hard water scale deposits. Ensures longer engine life and smoother performance.
Moreover, this antifreeze is designed to prolong your engine’s lifespan. Upon the initial filling, it’ll be in service for 3 yrs/ 7000 hours/ 300,000 miles. Whichever comes first. Although regular check-up is recommended.
Besides, it contains virgin ethylene glycol that prevents from freeze and boil-over. And the hybrid corrosion inhibitor package of organic acid protects your cylinder liners from cavitation, rust, and corrosion.
Mopar 50/50 Prediluted Antifreeze
This coolant also offers standard protection for your Cummins engine. It’ll protect from rust and corrosion as well as from scales, liner pitting, voids, and other possible damages to your engine. It also prevents from overheating and enables your engine to function properly.
This coolant has an exceptionally long service life. Can last up to 10 years in a single filling. Although, if your engine reaches 150,000 miles before that, you should change the coolant earlier. This OAT added coolant also prevents freezing down at -34 degrees C and boiling up at 129 degrees C. However, check your manufacturer’s recommendations and user manual before settling for any coolant/antifreeze.
Fleetguard Extended Life 50/50 Prediluted
This blue coolant is rich with proprietary scale inhibitors for maximum protection. Also, it’s free from conventional elements like Phosphate, Silicate, & Nitrite. Prolongs engine life and protects from scales, liner pitting, & corrosion.
It also offers freezing and boil-over protection. Letting your engine withstand -37 degrees C to 130 degrees C. It’s also compatible with other coolants.
Additionally, the Fleetguard coolant has very long service periods. Upon the initial filling, your engine will run for 150,000 miles or 4000 hours. So it saves you from the hassle of frequent refilling and a lot of expense.
Since it’s recommended by Cummins, you can use it as Cummins ISX coolant type as well as 5.9 Cummins coolant type and 6.7 Cummins antifreeze.
Cummins Antifreeze Buyer’s Guide
To fish out the best antifreeze for your Cummins diesel engine, you have to consider a few things. Several key factors include coolant type, specifications with engine model, type of your vehicle, etc. Alongside this, you should also learn how to change the coolant.
Cummins Antifreeze Type
There are 4 different types of Cummins antifreeze/coolant products on the market. The range works mostly between cost-effective products that require frequent maintenance and extended-life low-maintenance products.
The major types are as follows.
HOAT – Hybrid Organic Acid Technology
Recommended as the 5.9 Cummins coolant type as well as the 6.7 Cummins coolant type. Mostly a combination of a few inhibitors existing in IAT and OAT coolants. It’s usually low in silicate, contains a nitrite or molybdate-based technology. These coolants however need to be serviced with additives during service intervals. Low maintenance frequency.
IAT- Inorganic Acid Technology
The IAT coolants are low in silicate and they’re typically used in cars and light trucks. Usually green or pink in color. For heavy-duty engines, however, IATs contain pre-charged supplemental coolant additives (SCAs) to protect your engine from pitting and corrosion. A bit downside is that these coolants need frequent service as well as supplemental additives for a properly working cooling system.
OAT – Organic Acid Technology
This coolant uses organic acids for extended service life. It lasts longer than IAT varieties and perfect for use in all heavy & light-duty diesel engines. You could also use them in natural gas and gasoline engines. Besides, this coolant can provide up to 1M miles or 20,000 engine hours of service without additives.
NOAT – Nitrated Organic Acid Technology
Similar to OAT coolants in service life and performance. The only difference is that it contains nitrite and sometimes molybdate to employ engine liner pitting protection. The NOAT coolants may require an extender during the service period.
Cummins Engine Coolant Specifications
Cummins has a detailed coolant recommendation & specification guideline. According to it, the coolant should meet the ‘CES 14603’ specifications. In this case, Cummins officially recommends the “FleetGuard” heavy duty coolant for diesel engines.
You should change the coolant at the required intervals. Add necessary extender or additive during the filter change. Also, they suggest that you check the coolant at regular intervals for linear pitting. If any of the coolant life benchmarks appear, change the entire coolant.
How to Change Antifreeze
Usually, truck antifreeze or coolant products have a generous service life. Typically they are in service for 100,000 miles+, or 2 years+, or 5000 hours+ engine life. Whichever comes first. Once any of those parameters are reached, you have to completely change the coolant.
Changing your Cummins Antifreeze isn’t that difficult. Do it by yourself following this video.
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