Can You Use RV Antifreeze in a Car?

You might be one of the privileged ones waiting for the holiday to start to jump into your RV and hit the road. Whether you lack antifreeze in the car or RV, you might wonder, can you use RV antifreeze in a car? Let’s dive into a few factors around RV antifreeze and why you should keep the two separate instead.

What Is RV Antifreeze?

What Is RV AntifreezeIn the case of RVs, antifreeze means precisely that – a liquid is poured into the pipes to ensure it doesn’t freeze in winter months or when you travel through cold towns and destinations. The antifreeze can be pumped through the plumbing of the RV by using the water pump. This way, you protect the pipes and ensure there are no unsuspected bursts in the future.

Some might think of adding antifreeze to the expansion tank of the RV as well, but this is not necessary. The water tank is usually big enough not to be influenced by frost. RV antifreeze is usually a bright pink-colored liquid with a sweet smell. The taste, however, can be unpleasant.

What Are the Chemicals Found in Antifreeze?

Antifreeze can be divided into two types, which differ entirely. Automotive antifreeze, which you use in cars as a coolant, and RV antifreeze, used in motorhomes in the pipes. These antifreeze solutions differ in composition and have different percentages of chemicals. Other antifreeze chemicals are sometimes used in food and act like antifreeze without toxicity.

Ethylene Glycol

Ethylene Glycol has no color or odor. It is the primary chemical in most types of antifreeze regarding automotive. Ethylene Glycol lowers the freezing point of water and increases the boiling point. Thus, water flowing through pipes and radiators will freeze at lower temperatures than the norm. Ethylene Glycol is a water-based alcohol with high toxicity and can cause death when ingested.

The freezing point is 10.4°F, and the boiling point is 386.6°F. Thus, better used in a car’s cooling system and will prevent overheating.

Propylene Glycol

Propylene Glycol is odorless, colorless, and has a syrup-like texture. It is mainly used in food, cosmetics, and motorhomes as antifreeze because of its low toxicity. It is also a water-based alcohol, but because it reacts to many solvents and carbon, it is safe to ingest or use on the skin in small amounts.

The freezing point is -74.2°F, and the boiling point is 370.4°F. This composition is thus better in an RV antifreeze to ensure the water in pipes doesn’t freeze in colder months.

Calcium Chloride

Calcium Chloride is an inorganic chemical that will lower a liquid’s freezing point when added. The color is white, with a salty texture until it meets the liquid. It will, however, cause corrosion of metal parts if used as antifreeze in these systems. People use Calcium Chloride in food, sports drinks, and fire extinguishers.

Sodium Chloride

Sodium Chloride is white in color and tastes salty, as the known name for this component is table salt. Vast amounts of Sodium Chloride get used on roads to keep them from freezing. Because of the saltiness, Sodium Chloride is not suited for any antifreeze in pipes or engines. It should only be used on roads and in food.

Magnesium Sulfate

Magnesium Sulfate is white before being added to a solution and is inorganic. When added to water, it becomes colorless and odorless, with a bitter taste. Manufacturers use Magnesium Sulfate in cement composition, giving it extraordinary antifreeze abilities. In addition, it is not toxic to the body and can be used as medicine.

Can You Use RV Antifreeze in a Car?

The antifreeze you use in an RV doesn’t have the same purpose as the antifreeze in a car. Yes, you want to prevent water or liquid freezing, but the compartment you add the antifreeze to makes a big difference. In an RV, you want to use antifreeze in the pipes to ensure the water doesn’t freeze. This water is the water you drink and use to shower and wash dishes within your motorhome.

The antifreeze in a car prevents the water from freezing or overheating in the radiator. This water is never ingested, and the importance of this water not freezing or overheating is essential. Thus the chemical used in the automotive coolant is not the same as those in the pipes of an RV.

What Is the Difference Between RV Antifreeze and Car Antifreeze?

There are significant differences between the antifreeze we use in cars and RVs. Firstly, the antifreeze you use as a coolant in your vehicle’s cooling system will be Ethylene Glycol-based. The antifreeze you will use in an RV’s water pipes will be Propylene Glycol-based.

Ethylene is highly toxic and can cause poising or even death when ingested. Therefore, these ingredients should never be used in water pipes people drink from. On the other hand, Propylene is safe, and although not made to be consumed, it won’t cause sickness but only an unpleasant taste of the water.

Although you get Propylene Glycol-based coolants for cars, these are still different than RV antifreeze, and you shouldn’t use RV antifreeze in your vehicle. A bottle of antifreeze composition includes 90% of Glycol and 10% additives. That 10% can make or break your car.

The additives will work against corrosion in a car, and it won’t matter if it is toxic for people. Antifreeze also increases the boiling point of the water, which is crucial in a car engine’s cooling system. On the other hand, RV antifreeze doesn’t have to work against severe corrosion but needs to focus on safe products.

Colors usually label coolants for vehicles, and this is also possible if you want to buy antifreeze according to color. Follow the vehicle’s manufacturer’s manual to ensure you use the correct color antifreeze.

What Are the Types of (RV) Antifreeze?

(these are not RV antifreeze specifically, but antifreeze for engines)

When we look into the different types of antifreeze, we get organic, inorganic, and hybrid systems. Each is different, has various colors, and has other uses.

Organic Acid Technology

Organic acid technology (OAT) was introduced in 1996 with a pink or orange color. The additives of these organic acids have a better effect on cooling down the system. Still, the corrosion properties are less than the inorganic acid coolants. However, Japanese companies, Toyota and Honda, prefer OAT coolants.

Inorganic Acid Technology

The inorganic acid technology (IAT) was the first coolant on the market with a neon green color. The ability to prevent corrosion is excellent, and thus the best to use in old model cars with brass engines and pipes. The color of this inorganic acid antifreeze nowadays is green or yellow. It uses Propylene which is safer for pets that can access the garage.

Hybrid Organic Acid Technology

The hybrid organic acid technology has the best of both IAT and OAT. The OAT’s long-lasting effect and the IAT’s better corrosion control. The color will typically be a faded yellow color. German car manufacturers usually prefer these “G-5” HOAT coolants.


Dex-Cool is not called antifreeze, but it has the same purpose. General Motors formulated this orange or sometimes red antifreeze product almost identical to Organic Acid Technology but with no silicates and phosphates.

Although it is a cleaner product and also lasts longer than IAT, there have been problems with Dex-Cool when the levels were low. Thus, some car companies ban Dex-Cool from being used in their engines.

Can RV Antifreeze Be Mixed With Water?

Experts don’t recommend that you mix water with your RV antifreeze. The readily bought cans of liquid RV antifreeze are combined with a 50/50 ratio of antifreeze and water. If running low on RV antifreeze, you can temporarily add pure distilled water to alleviate the problem. You must, however, get to a professional to flush the system before adding new antifreeze to your RV ASAP.

Can You Put RV Antifreeze in a Car Radiator?

Antifreeze in a Car RadiatorAdding RV antifreeze to your car radiator can be a significant risk and most likely lead to problems with your car on the road. Your vehicle could overheat, rust, or cause damage to the pipes if you add RV antifreeze to the radiator. As we mentioned before – RV antifreeze prevents water from freezing in tubes, not cooling down a system in a car with different components and metals.

Can RV Antifreeze Melt the Ice?

Unfortunately, RV antifreeze can only prevent water freezing in the pipes, not melt frozen water. The key for using RV antifreeze is to drain the pipes before winter, then pour in the antifreeze to protect the pipes and faucets from freezing. The composition is designed in a way to prevent and not unfreeze water.

Can I Use RV Antifreeze as a Windshield Washer?

RV antifreeze cannot work as a soapy liquid to wash the windscreen. Although nothing terrible will happen to the car, the driver would be at risk and the windshield. Others may use it as an addition to the soap to prevent the windscreen from freezing. This could work, but the cons are more than the pros.

First, the solution will cause a greasy smudge over the windshield that can lead to the driver’s vision being blocked. Secondly, the pink color of the RV antifreeze can discolor the windscreen, and the wiper’s corrosion is possible.

Can I Use RV Antifreeze for Motorhome Engine?

Suppose you use RV antifreeze in your motorhome’s engine; you won’t get too far. The problem is that RV antifreeze can’t prevent the engine from overheating. That is why any engine will need coolant like a car antifreeze.

The RV antifreeze is only for the motorhome’s plumbing system. This part of the motorhome has nothing to do with the engine of the motorhome.

Can You Mix RV Antifreeze and Car Antifreeze?

No antifreeze should ever be mixed. Not even different brands of car antifreeze, and less so with RV antifreeze. The additives to each can cause a reaction that no one can predict. If this happens accidentally, drive as slowly as possible to the nearest automotive shop for a total flush and keep an eye on the heat gauge.

Frequently Asked Questions

  1. What Is The Difference Between RV Antifreeze And Regular Antifreeze?

RV antifreeze is designed to keep the plumbing system of a motorhome clear of frost or bursting pipes. Regular antifreeze should be used to keep the engine and radiator of a vehicle cool and prevent overheating.

  1. Can You Use RV And Marine Antifreeze In A Vehicle?

The only engine suitable for RV and marine antifreeze is a motor boat. Any other engine needs regular antifreeze that can prevent the system from overheating. Although RV antifreeze can be an emergency substitute, there could still be consequences, and the correct coolant should be used instead.

  1. Is Caravan Antifreeze The Same As Car Antifreeze?

Caravan antifreeze for the plumbing system would be the same as RV antifreeze. For the engine, you would need car antifreeze. But the two differ; it depends on which system you need the antifreeze for and which you refer to.

  1. What Is The Difference Between Marine Antifreeze And Automotive Antifreeze?

Although marine antifreeze is used in boats’ engines, the difference between that and automotive antifreeze is its toxicity. Any leakage of dump from a boat’s engine should not impact the sea life. Marine antifreeze uses Propylene Glycol, which is safer than Ethylene Glycol in car antifreeze.

  1. When Do You Have To Change The Antifreeze In Your Car?

When your car is compatible with Organic Acid Technology or Hybrid Organic Acid Technology, you only have to replace it every 5 years or 150 000 miles. However, when using Inorganic Acid Technology, you need to renew the antifreeze by three years or 36 000 miles.

  1. What Do The Antifreeze Colors Mean?

The antifreeze colors usually point out what type of antifreeze it is, and you should inquire from the manufacturer manual which type your car is compatible with. For example, green indicates IAT antifreeze, while orange or pink will usually be OAT antifreeze. Hybrid OAT will be a faded yellow, and Dex-Cool can vary between orange and gold. Shocking neon pink is usually RV antifreeze color.

  1. Can You Use Car Antifreeze As Plumbing Antifreeze?

You cannot use car antifreeze as a plumbing antifreeze. The toxicity can intoxicate the water, leading to the poising of people who drink the water with traces of antifreeze left. In addition, the freezing point is not low enough to prevent severe weather conditions.

  1. Can People Use RV Antifreeze In A Boat Engine?

Although RV antifreeze has the same qualities as marine antifreeze, the composition still differs. The similarities are that the toxicity is low in both. RV antifreeze, however, works in plumbing systems and regular antifreeze in engines.

  1. Is An RV Antifreeze Toxic?

RV antifreeze has low toxicity when ingested in small amounts. The manufacturers designed it this way because people use it in plumbing pipes which might end up in a glass of water. Vast quantities, however, could be harmful to people and pets.

  1. Do You Have To Use RV Antifreeze In Summer?

It is not necessary to use RV antifreeze in the summer months. It isolates the plumbing pipes to keep them from freezing. Thus, doing this in the summer would be a waste of money. However, it would help to winterize your RV before winter because RV antifreeze cannot undo frozen pipes.

Final Thoughts

The best plan is to follow the manufacturer’s manual for your vehicle or motorhome to ensure you use the correct antifreeze. Don’t risk your vehicle’s engine by using RV antifreeze, and steer clear from antifreeze that states “for any vehicle and engine.”

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