Tag: oil leaks on deck of riding lawn mower

Lawn Mower Repair Tips, Push and Self-Propelled Lawn Mower Repair, Riding Lawn Mower Repair, Zero Turn Lawn Mower Repair

Lawn Mower Leaks Oil From Crankcase

Occasionally we see an oil leak from the crankcase gasket that seals the two halves of the crankcase together. Or a pinhole develops in the actual casting of the crankcase and oil will seep out of it. Other areas that leak are protrusions through the crankcase such as the governor arm shaft. Head gaskets can be another source of an oil leak out of the crankcase. An oil seal at the crankshaft is another oil leak source.

Note: Be extra cautious during the testing as you are working near a lawn mower blade. You can shutdown the engine prior to checking for where the engine is leaking for safety.

There are some dyes that can be added to the oil to find a hard to find oil leak. You put the dye in the crankcase and run the engine to get it warmed up. Then a black light is used to identify where the oil leak is coming from.

If you don’t have access to this type of testing paraphernalia, thoroughly clean the engine crankcases and then run the engine until it is warm. Look over the areas that you suspect the leak is coming from and look for the slightest weeping of oil. Wipe the area down and continue to monitor it.  Some leaks are difficult to find, but you will eventually find them.

Riding Lawn Mower Repair

When I Start My Riding Lawn Mower it Throws Oil Everywhere

You talk about a mess…yes this is one mess maker for sure. You turn the key and start your riding lawn mower up and then spots of oil appear all over your deck and the ground. But what could be causing this?

Well, there are a few things that can cause this. The more common one is the crankshaft oil seal at the bottom of the engine. To check this, a mirror and a flashlight are helpful to be able to see if it is leaking. Oil will normally pool in the drive pulley that is connected to the bottom of the crankshaft. When the pulley starts to turn during starting, the oil is centrifugally slung out of it and spews everywhere.

If the leak is not there, you can move onto the oil drain plug. It could be a square drive plug in the bottom of the crankcase or a twist lock style with a cap on it. These have a tendency to unscrew over time and loosen up. Check them for tightness.

Next check the crankcase seal itself. There is a seal between the two crankcase parts that must be intact and tight to prevent oil from leaking. If that is good it is onto the oil filter. Make sure that it is not leaking as well.

Another possibility is the valve cover gaskets or the cylinder heads themselves. So check them to be sure that they are not leaking.

When you find the source of the leak, contact a riding lawn mower repair professional on our locations page for assistance.