If your Toyota 4Runner V6 has sprung an oil leak, there are several ways to fix it. And you should tend to it quickly: if your 4Runner runs low on oil, then you may risk damaging your engine and risk its moving parts seizing. Running out of oil can cause catastrophic failure, which will require a completely new engine or a rebuild by a professional mechanic.
Open the hood on your 4Runner while the engine is cold and check the oil by removing the oil-check dipstick. Wipe the dipstick clean with a cloth and reinsert it into the dipstick check-tube. Remove the dipstick once again, checking the oil against the minimum and maximum lines printed on the dipstick. If the oil level exceeds the maximum line on the dipstick, then the extra oil is leaking out through the gaskets and seals due to excess oil pressure. Drain the oil, using the process described in step 3, and refill the oil system with the proper amount of oil.
Add an oil-thickening additive if the oil level is low. Oil additives not only serve to thicken the oil in your 4Runner system, helping to stop or prevent leaks, but can also help lubricate and protect different engine components. Allow your engine to run for a few minutes so the oil additive can mix in with the oil and check the oil level again, making sure that the oil is at an appropriate level.
Drive your 4Runner onto a pair of car ramps. Use an oil filter wrench to remove the oil filter, allowing the oil to drain into a catch pan. Replace the oil filter with a new one. Unscrew the oil drain plug and allow the oil to drain from the 4Runner's engine. Screw the drain plug back into place. Pour in a heavier weight oil to replace the old oil. Sometimes a heavier oil will help to reduce leaks.
Replace the leaking gasket as a last resort, which usually requires much more work and in many cases, the help of a professional mechanic. Some gaskets, such as the top valve cover, can be replaced by the do-it-yourselfer though. Simply unbolt the top valve cover and remove the old gasket by gently prying it with a screwdriver. Clean the gasket groove with a lint-free cloth and install the new gasket. Use automotive gasket silicone to help create a tighter seal between the top and lower valve cover and bolt the top valve cover back into place. This basic gasket replacement process can be used for nearly every gasket within the 4Runner's engine system.
