Jeep Wrangler/YJ 1987-1995 Repair Guide




See Figures 1 and 2

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Fig. Fig. 1: Removing the engine oil level dipstick

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Fig. Fig. 2: Make sure the oil level is between the ADD and FULL marks

Make sure that your vehicle is on a level surface to ensure an accurate reading. Then, raise the hood, position the holdup rod, and measure the oil with the dipstick which is on the left side of 4-cylinder engines and on the right of 6-cylinder engines. Add oil through the valve cover filler hole.

If the oil is below the ADD mark, add a quart of oil, then recheck the level. If the level is still not reading full, add only one-half quart at a time, until the dipstick reads FULL. Do not overfill the engine. When you check the oil, make sure that you allow sufficient time for all of the oil to drain back into the crankcase after stopping the engine. A minute or so should be enough time.


See Figures 3, 4, 5, 6 and 7

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Fig. Fig. 3: Removing the engine oil fill cap from the valve cover

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Fig. Fig. 4: Removing the engine oil pan drain plug

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Fig. Fig. 5: Removing the engine oil filter with a strap wrench

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Fig. Fig. 6: Adding engine oil

The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

The engine oil is to be changed every 4,000 miles (6,441 km). The oil should be changed more frequently, however, under conditions such as:

Driving in dusty conditions
Continuous trailer pulling or RV use
Extensive or prolonged idling
Extensive short trip operation in freezing temperatures (when the engine is not thoroughly warmed up)
Frequent long runs at high speeds and high ambient temperatures
Stop-and-go service, such as delivery vehicles

Under such conditions, the oil change and filter replacement intervals should be cut in half. Operation of the engine in severe conditions, such as a dust storm, volcanic ash or deep water, may require an immediate oil and filter change.

Before draining the oil, make sure that the engine is at operating temperature. Hot oil will hold more impurities in suspension and will flow better, removing more oil and dirt.

Drain the oil into a suitable receptacle. Waste oil may be disposed of at a garage or service facility which accepts waste oil for recycling.

  1. Position a suitable drain pan beneath the oil drain plug.
  3. Loosen the drain plug, then unscrew it with your fingers, using a rag to shield your fingers from the heat. Push in on the plug as you unscrew it, so you can feel when all of the screw threads are out of the hole. You can then remove the plug quickly with the minimum amount of oil running down your arm. You will also have the plug in your hand and not in the bottom of a pan of hot oil.
  5. Wipe off the plug while the oil drains. If so equipped, install a new crush gasket.
  7. When the oil has finished draining, or has slowed to a trickle, install the drain plug. Tighten the plug, but be careful not to damage the threads.

Change the spin-on type oil filter every time you change the oil. Make sure that you have a pan under the filter before you start to remove it from the engine so you won't make a mess and, if some of the hot oil does happen to get on you, you will have a place to dump the filter in a hurry. The engine should be at operating temperature.

  1. Loosen the filter with an appropriate oil filter wrench.
  3. With a rag wrapped around the filter, unscrew the filter from the oil pump housing. Be careful of hot oil that might run down the side of the filter, especially on 6-cylinder engines.
  5. Wipe the base of the mounting plate with a clean, dry cloth.
  7. Smear a small amount of clean oil on the gasket with your finger, just enough to coat the entire surface where it comes in contact with the mounting plate.
  9. Screw the new filter by hand onto the oil pump housing. Do not use the oil filter wrench! Tighten the filter only a quarter of a turn after it comes in contact with the mounting plate.