Reasons My John Deere Mower Would Leak Oil

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Try to find the source of oil leaks quickly.
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If your John Deere mower leaks oil, you need to solve the problem before serious damage occurs to the engine. Sometimes the needed repair is very small and won't cost you much money. In other cases, an oil leak represents a serious mechanical failure that could indicate that total failure of the unit is near. This is why identifying the cause of an oil leak is essential.


Cracked Oil Seal

The oil seals are the first thing you should check if you see an oil leak on any model mower. The exact location and shape of the seals will differ depending on the model of your mower, but most of the time the leaking one will be located just above the blade, under the engine. Buy a replacement seal, pry the old one out and press the new one firmly into place. Make sure that it doesn't wrinkle or bend when you put it in to avoid further leakage.


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Drain Plug

To change the oil in a John Deere mower you typically remove a drain plug from the bottom side of the engine so that the old oil can run out through the drain tube. If that cap is not properly replaced, or if the vibrations from the engine loosen it or make it fall off, you will quickly discover an oil leak out of this portion of the engine. Wipe the oil from your engine and run it to see if you can spot where the leak is coming from. If it emerges from the drain, simply replace the cap properly.


Oil Fill

Sometimes an oil leak is not a sign of anything serious at all. This is the case when the oil is leaking from the area where you add oil to the engine. Always ensure that you use the oil recommended in your model's owner's manual to prevent causing problems in the oil system. When you put the cap back on after adding oil to the mower, it is easy enough to fail to tighten the cap properly afterwards. An O-ring seal on the opening keeps oil in the engine. Loosen the cap, remove the dipstick and press the ring firmly back into place before you tighten the cap again.



Oil will also leak out of cracks or holes that are not supposed to be in your engine. If the engine block cracks anywhere the engine may still run, although it might do so poorly, but oil will leak consistently from the system. Over time, this is likely to lead to severe engine damage. Sometimes a small crack can be welded, but damage like this may spell the end for an engine.



When you park your mower for any prolonged period of time, you should park it on a flat and level surface. Leaving the vehicle on uneven ground could cause an oil leak. Also, if you check the oil while parked on a slope it may read low, causing you to overfill the engine. This will also lead to leaks.



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