Can you use car coolant in a motorcycle? If you have no recommended option available, you may use car coolant or antifreeze in your motorcycle, but make sure the OEM (Original Equipment Manufacturer) specifications match. Anyways, there’s a lot to learn from this article.
First, note that antifreeze, also called coolant, keeps water from freezing, and water freezes at 32 degrees Fahrenheit. A typical liquid cooled motorcycle uses a radiator and has a coolant reservoir. Most liquid cooled motorcycles use a mixture of 50% coolant and 50% water to expel heat from the engine through the radiator(s).
The radiator cools the engine, and a reservoir holds the coolant, which keeps water from freezing to avoid damaging the radiator. So, when you apply coolant in the reservoir, it reduces the freezing temperature for the motorcycle to operate in optimal temperature and condition. We have liquid cooled and air cooled motorcycles, but only liquid cooled motorcycles use radiators.
Do Motorcycles Need Special Coolant?
Yes, motorcycles need special coolant. However, if you are tempted to use a car coolant for your motorcycle reservoir, make sure the spec is the same. But for long-term solutions, use the recommended coolant/antifreeze for your motorcycle. We have ethylene glycol and propylene glycol, but a propylene glycol is a good option for your motorcycle; you must not mix these two coolant variants.
Is Motorcycle Antifreeze the Same as Car Antifreeze?
A motorcycle antifreeze is not necessarily the same as a car antifreeze. There are a few differences in chemical properties between a car coolant and motorcycle coolant, and most experts recommend using recommended motorcycle coolant only. The difference is not drastic, though. As mentioned earlier, make sure to buy the coolant that contains ethylene glycol antifreeze for your bike.
Can You Use Car Coolant in a Motorcycle?
Yes, you can use a car coolant in a motorcycle. But ensure that the antifreeze/coolant pack lists the specification. Next, check your motorcycle owner’s manual to verify whether the specifications match. A typical older Vstrom owner manual does not specify beyond 50% ethylene glycol. But it is also advisable to use silicate-free coolant in an aluminum engine.
A vehicle and motorcycle cooling systems have no drastic difference except the size, but make sure the OEM spec corresponds.
Car coolants are typically ethylene glycol-based, not OK for your motorbike. So, if the coolant contains ethylene glycol antifreeze, you may use it on your bike. As mentioned earlier, the coolant should not contain silicate to avoid damaging the seals of your motorcycle engine. Typically, coolants that use silicates and phosphates (depending on the motorcycle) can destroy an aluminum engine, though.
Now, suppose a car coolant bottle label reads something like:
GREEN is an ethylene glycol-based antifreeze/coolant specifically developed for any vehicle requiring a phosphate-enhanced Green formulation. It contains high-quality organic acid technology (OAT) corrosion inhibitors and is free of borate, silicate, nitrite, and amines chemicals.
But the owner’s manual only mentions silicate inhibitors as a problem and does not specify phosphates, you may use them in your bike. Besides, silica is anti-corrosive. The label, however, shows that the coolant is silicate-free, which is good for your bike.
GREEN could mean that a coolant is made from an older formula that uses ‘Inorganic Additive Technology’. So, Green properties or formulas can protect your motorcycle cooling system metal against corrosion and rust if it is aluminum.
Note that coolant has more to do with a closed system, meaning that it has no contact exposure.
What’s Silicate? Good for Your Bike?
In most cases, silicate is not good for a motorcycle, and experts recommend using only silicate-free coolants for a motorcycle that does not need it. You may check your bike owner manual and compare it with what the coolant label reads.
Silicates are similar to salt or tiny sand-stones capable of grinding your hoses and preventing any build-up. If used in some Honda bikes, for example, it can wear the gaskets, resulting in a leaky water pump.
Nevertheless, some motorbikes use silicates, and some use phosphates. Depending on the manufacturer, a motorcycle may use silicates and phosphates; check the owner’s manual.
Before You Add Car Coolant to Your Motorcycle
Furthermore, on the question, “Can you use car antifreeze in a motorcycle?” Before you add antifreeze/coolant to your motorcycle, check its compatibility. Coolant is quite different from what it used to be when everything was Inorganic Acid Technology (IAT), the conventional/traditional green antifreeze, and fully compatible.
Today, we have OAT, HOAT, GREEN, etc. OAT and HOAT are not compatible; they will sludge and gel when mixed. If you added a car coolant that is incompatible with your motorcycle by mistake, flush the coolant system.
Also, if you dislike DEX-cool (OAT), most green coolants are dyed OAT coolants. The reason is that bikers fondly mix wrong coolants. But if you need the traditional or conventional green, read the label carefully or inform the manufacturer or vendor.
It may be challenging to find the appropriate coolant, though. If you use any auto coolant instead of motorcycle coolant, you can flush and replace it later with what the owner manual recommends. Meanwhile, during the COVID lockdown, our staff had failed hose clamps with leaking coolant. He topped it with incompatible coolant from AutoZone and rode home since they didn’t sell distilled water. When he arrived home, he flushed the coolant reservoir, which had no negative impact.
You may order a new coolant or let the bike repair shop handle the flushing and replacement while you the bike for periodic maintenance.
All coolants are not the same, and there are reasons why manufacturers list various standards in the bottle label and motor vehicle owner/user manual.
If only one or no specification between the user manual and coolant label match, do not use the car antifreeze/coolant in your motorcycle. But if more or all specifications match, you can use a car antifreeze/coolant in your motorcycle.
Most bikers use standard automotive coolants in dirt bikes and other motorbikes, though. You may read how to recover towed dirt bike. Besides, we have specialty coolants like Engine Ice and Evans coolants, which are a bit efficient and useful in extreme conditions.
In essence, it’s okay to use some automotive coolants in motorcycles, but coolants with anti-corrosives may not be advisable, depending on your motorcycle.