My Motorcycle Is Leaking Coolant

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There are many advantages of owning a motorcycle that is water cooled including more effectively controlling the engine’s temperature and thermal efficiency. But, like most things, it also has it’s drawbacks.

Leaking coolant on a motorcycle can be incredibly frustrating, especially when you’re unsure where the leak is coming from and why it’s even happening in the first place.

Why is my bike leaking coolant A motorcycle can leak coolant for many reasons, including broken or loose drain plugs, faulty clamps connecting the radiator to the engine, and faulty hoses. The coolant can also leak from punctured radiator fins, a leaking water pump, or excessive heat engine pressure.

Although the cooling system for a water-cooled motorcycle is simpler than that of a car, there are still many things you need to be aware of when riding a bike like this. This article will show you how to identify and fix a coolant leak.

There are many reasons to leak coolant

Many years ago, water cooled motorcycle engines weren’t near as prevalent as they are today. It’s becoming more and more common among newer motorcycles because of how efficient the system is compared to air cooled engines.

To tell for sure if it’s a coolant leak you’re dealing with, assess the liquid you see leaking from your motorcycle. Antifreeze can come in all different colors, but the most common color you’ll see is a neon green. If you’re still unsure, try to smell it; coolant will have a distinct sweet smell that the other fluids won’t have.

Loose radiator hoses are the leading cause of motorcycle coolant leaking. All motorcycles that have a radiator have an upper and lower hose; there’s an engine connection on the top and bottom and a radiator connection on the top and bottom. There are four points where the radiator’s hoses could fail.

This is often caused by the connection between hose and engine not being tight enough. To keep the hose in place, there are usually metal clamps at each end. One could have fallen off, or the end may be cracked and corroded.

Additionally, Sometimes, mechanics and motorcycle owners may tighten the clamps on the end of the radiatorhoses too tightly. These clamps need to be tight, but don’t require to be extremely tight. These clamps should not be too tight as they can tear the hose or cause holes.

The drain plug is another common point of failure that can cause coolant to leak from a motorcycle. Most radiators come with a small, plastic hand screw that is very cheaply made and can easily be broken. You can even cause them to break by tightening it with your hands. These drain plugs may become loose or corrode over time due to constant vibration from your motorcycle.

If none of these are the causes of coolant leaking on your motorcycle, you should look at the radiator. You will find small tubes or fins running throughout the radiator. These tubes are where coolant flows to cool down and circulate throughout the engine.

Because the radiator is located at the front of the motorcycle it’s possible that some sort of rock or road debris punctured a hole in one or more of those tubes/fins which would cause it to leak.

The water pump is next. Water pumps have a small hole in the bottom. The water pump has fan blades that circulate coolant through your motorcycle’s engine. It has a small bearing that allows the blade to turn freely and quickly. It wears over time and becomes looser.

Coolant seeps through bearings when they become worn. It’s made this way on purpose because if a mechanic sees the water pump leaking or notice any corrosion, they can quickly know and diagnose a bad water pump. The location of the water pump varies on each motorcycle, so look in your owner’s manual to find it’s location.

It’s also possible that your motorcycle engine is overheating and is creating pressure that causes the radiator cap to leak If your motorcycle is equipped with a coolant reservoir you might also need to replace it. You should never take off your radiator cap if it is suspected that your motorcycle is experiencing a leak. It is possible for the pressure to build up again and spread antifreeze wherever it opens prematurely. Allow at least 30 minutes for the cap to be removed.

How to Fix Leaking Coolant

Most coolant leaks are easy to fix. If you’ve noticed any corrosion, cracks, or holes in the radiator hose(s), you’ll need to simply replace those. These usually cost only a few dollars.

Verify the tightness of the clamps that hold the radiator hose. If they’re too tight, remove them and assess the condition of the hose they were clamped to. Again, if you notice any tears or holes, you’ll need to replace the hose altogether. Be sure to place and tighten the clamps at a reasonable tightness; don’t get them so tight that you break the hose underneath it.

Also, new drain plugs can be purchased at a very affordable price. You can also replace the drain plug if you notice a leak. Instead of saving it, just replace it. These are only a few dollars, and they will likely need to be replaced anyway.

If those weren’t the sources of your leak, the cost to fix the leak from here on out goes up a little bit. If you’ve found the leak is coming from the radiator, you’ll need to get a new radiator altogether. It’s almost impossible to fix a punctured fin without causing more problems since they’re so small. A motorcycle radiator can be easily replaced by a beginner. It usually costs between $30 and $100.

Unless you’ve replaced and dealt with a water pump before, I recommend you take your motorcycle in to a shop and have them replace it for you if that’s the issue you’re dealing with. That is not a beginner’s task and could have terrible consequences if done wrong. It will probably cost between $100 and $300.

Water cooled motorcycle engines are less likely to overheat than solely air cooled engines simply because it’s more efficient. But if you notice you’re leaking coolant from the radiator cap because of an overheated engine and know the cap is good, you’ll need to check a few thing about the engine itself.

First, notice how you’re riding your motorcycle. If you’re constantly in traffic in hot temperatures or constantly revving the engine, this will likely result in an overheated engine. Make sure you have enough oil in your engine. Oil acts as a coolant and can cause the engine to overheat, and even seize.

How to Prevent Coolant Leakage

Basic maintenance is the best way to prevent coolant from leaking on a motorcycle. Be sure to occasionally check the status of the hoses and ensure they aren’t cracking or becoming loose.

Check the coolant level every so often and top off if necessary. Although coolant can last quite a while, motorcycles will still need to be topped off occasionally. Overheating can lead to engine failure and more coolant loss.

Water-cooled motorcycles should be flushed every 30,000 miles, or every five years, depending on which comes first. This isn’t very often you’ll need to do this, but don’t skip it once it’s time to do it.

If you leave it unchecked, the consequences

Coolant leakage on a motorcycle should not be ignored. It should be immediately attended to. A water-cooled engine’s coolant is as important to it as the oil that runs through. This issue can have serious consequences if it isn’t addressed.

A motorcycle that leaks coolant will mean less coolant is circulated throughout the engine. It can get to a point where there simply isn’t enough coolant in the system to cool down the engine which will make the engine really hot.

The coolant is supposed to protect the engine from heat, pressure and friction, so the engine can get really hot and the pistons will begin moving up and down in their chambers. A coolant leak can eventually lead to a seized motor. You can read my article about a seized motorbike engine.

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