Car Oil Leak Symptoms
So you see a dark patch appear under you car engine after you have had an Oil Change.
What they do during the Oil Change
During an Oil Change, two items are removed from the engine. One is the Oil Filter, which is replaced with a new Oil Filter. The other is the Drain Plug that goes into the Oil Pan. This Drain Plug is put back into the Oil Pan after all the old oil has been drained out. Initially a few hours after an Oil Change you may have a little bit of oil drip as some engines have the Oil Filter in such a way that Oil will spill onto the engine as the filter is being changed. After a few hours, you should no longer have any sign of oil dripping.
Where is the Leak?
First of all you need to determine if the Oil Leak is coming from the Drain Plug or the Oil Filter. See below for descriptions of the Drain Plug and Oil Filter.
Drain Plug Leak
At the bottom of the engine is the Oil Pan. Into the side or bottom of this Oil Pan is a bolt called the Drain Plug. Common reasons for a leak here are:Gasket part of the Drain Plug is worn or Dirty and so the Drain Plug no longer has a tight seal on the Oil Pan. To fix, drain oil out of oil pan into container for recycling. Clean Drain Plug and part of Oil Pan it goes against and/or purchase new Drain Plug. Put Drain Plug back in Oil Pan and refill engine with correct amount of oil and oil type.Drain Plug was not tightened all the way so it does not have a tight seal on the Oil Pan. To fix, take wrench that matches size of Drain Plug hex end and tighten up.Drain Plug was cross threaded when put back on the Oil Pan. This is where the Drain Plug is not put back in correctly and the mechanic forces it on using a wrench and in the process destroys the thread of the Oil Pan. This is very common on cars that have an aluminum Oil Pan. Only two ways to fix are either to have the Drain Pan replaced or buy an expanding rubber plug that replaces the original Drain Plug. Both fixes require the Oil to be drained out of the engine. With the rubber plug Drain Plug, it fits in the Drain Plug hole and a bolt compresses it to make it expand and seal the hole. Drain Pan replacement can be difficult if parts of the frame or suspension of the car get in the way of removing it.
Oil Filter Leak
Oil Filters can be located in various parts of the engine so you will need to look for a cylinder like object (like a soda can) that is on the side of the engine. Size varies from a half a soda can all the way to a large can of beans.
Oil Filters are spun on by hand onto the engine. Sometimes, it can feel like the Oil Filter is on all the way but it may not be. At the top of all Oil Filters is a gasket. Before a New Oil Filter is put on, this gasket is supposed to be lubricated with Oil. When this gasket touches the engine (as the new Oil Filter is screwed on), the Oil Filter is supposed to be turned a further 3/4 of a turn to form a tight seal. If for some reason the filter is not on tight enough, Oil will leak around the filter. To Fix, check if there is any gap between the Oil Filter and the Engine and that it is on tight enough.
Check out these other leaks for additional information on Car Oil Leaks .