In this article, we’ll take a look at the reasons your chainsaw might be leaking oil between uses, and what you can do to prevent this from happening.
Most chainsaws will leak some oil after use, but it should be a very small amount, no more than 20ml over three days – enough to make a spot about the size of a quarter.
If your chainsaw leaks more than this, it’s most likely caused by damaged or degraded parts or by improper oiling. Read on to learn more.
How to store a chainsaw without oil leaking
Oil leaks from overfilling the reservoir are more likely during storage than during use because ambient temperature changes can make the oil expand. For this reason, it is recommended to never top off the oil reservoir when placing a chainsaw in storage – instead, only make sure it is filled before each use. You should also test that fill plugs are tight before stowing the chainsaw away after use. Plastic or rubber plugs may also degrade over time, replacements are cheap, although for some brands they may be difficult to find.
If the leak is not coming from the reservoir but from inside the body of the chainsaw, it may be worth checking a few mechanical points. Check the oil pump, the oil tank vent, and the oil outlets around the clutch. If any of these are clogged, oil pressure may be building up until oil leaks out of the lines inside the tool. This oil then builds up inside the body of the chainsaw, and drips out through unsealed parts of the casing while in storage. This kind of issue is most likely if oil leaks while the chainsaw is in storage, but there is an insufficient amount of oil distributed to the chain while the tool is in use.
Consult the manual for your specific model of chainsaw for cleaning and maintenance procedures. In general, you will need to disconnect the spark plugs, remove the chain and the outer casing of the saw, and insert a wire brush into the oil ports to clear them. If the oil pump itself is clogged, it will likely need to be removed and thoroughly cleaned or replaced.
Why does my chainsaw leak chain and bar oil when not in use?
There are a few reasons a chainsaw might leak oil. Some are due to mistakes made in oiling the tool, while others are maintenance issues.
At all times, it is important not to overfill the saw’s oil reservoir. If the reservoir is overfilled, oil may leak out through the fill port. Your reservoir should be marked with a maximum fill level, and it’s best to stay a little under this level. Doing so should prevent most oil leaks during active use of your saw and while it is in storage. Another easy-to-fix issue that may cause oil leakage is a problem with the fill port plug itself. Make sure that you fully tighten the fill plug each time you top off the oil.
Mechanical problems are more likely to cause leaks during use than in storage. However, it’s still important to be aware that leaks may be caused by failures in other parts of the oiling system, such as pumps. This is more likely if the leak is coming from somewhere on the tool body that is not near the oil reservoir.
Is it normal for a chainsaw to leak bar & chain oil when in storage?
It is normal for many chainsaws to leak a small amount of oil after use. The oil in the reservoir itself should not leak, but depending on the design of the oiling system, the oil contained in the lines and bar rails – a total of no more than 20ml or about half a US fluid ounce – may leak out of the tool rather than seeping back into the reservoir.
It’s a good idea to place a rag under your chainsaw when placing it in storage, to catch this small amount of oil. You should be able to remove the rag after a few days. If there is any more leakage after that, it is likely your chainsaw has been overfilled with oil or needs maintenance.
A comparison of popular chainsaw brands
Stihl chainsaws can be expected to leak small amounts of oil over two to three days after use. This is oil that had already been pumped out of the reservoir, but had not yet been applied to the chain, when the saw was turned off. The fact that this small amount of oil takes so long to leak out is due to the high viscosity of chainsaw oil.
If your Stihl chainsaw continues to leak after several days in storage, or leaks more than the expected amount, Stihl advises that the most likely mechanical cause is an obstruction in the vacuum relief valve. This valve sits between the oil output hole and the bar studs. The valve should be closed when the chainsaw is not in use; this keeps air from entering the system, and creates a vacuum pressure effect that stops oil from leaking out. The valve may be stuck open if debris has entered it during use. Take a small needle or a bit of steel wire and push it into the valve – which looks like a small silver disk with a hole in the middle – a few times to loosen the debris. That should allow the valve to close, stopping air from getting in which will restore the vacuum pressure.
Husqvarna chainsaws can similarly be expected to leak small amounts of oil in the first few days after use. If there is still leakage beyond that point, Husqvarna suggests opening the saw’s casing and cleaning any sawdust or debris from the inside. Debris such as this can trap or absorb oil while the saw is in use, effectively significantly increasing the amount of oil that is sitting inside the tool during use. This oil, like that inside the oiling system itself, then drips out over time when the tool is placed in storage.
Many Husqvarna chainsaws also have a feature that allows you to set the oil output level using an adjustment screw. Improper adjustment can create leaks. If the oiling level is too high, the chain won’t be able to take up all the oil, and it will build up on the bar. If the level is too low, the pressure will build up inside the pump, causing oil to leak from inside the housing. You should aim to set the oiling level to the lowest level you can without causing a leak from the pump. This should also correspond to very small splatters of oil being emitted from the saw when it’s in use.
The most likely source of an excessive oil leak in Craftsman chainsaws is high pressure built up in the oiling system during use. As the saw cools, the pressure increases even further, and oil may leak out of various points in the oiling system. A good practice is to release the pressure from the oil system before stowing the tool by briefly loosening and re-tightening the fill cap. Larger or continuous oil leaks may be the result of the PVC tubing in the oil system either being damaged or coming loose from the pump. Either issue will be easily visible if you remove the casing and examine the tubing. PVC tubing is easily available and inexpensive to replace.
Similar to Husqvarna chainsaws, many Echo units have adjustable oilers, so your first approach to dealing with a serious oil leak should be to adjust the oiling level as described in the Husqvarna section above. Echo saws are also known for needing occasional replacement of oil reservoir vent plugs or silicone gaskets and grommets around the oil lines. Local dealers should have these parts available.
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