Yup. I know. Sounds easy... and it is. Problem is, we all know someone who doesn't/won't/or can't change their own oil and are taking miles of life off their engine!

Well, don't just sit there... Go give them a dope slap and tell them to take care of it!

If you've just been sent here with a good 'dope slap' and instructions to "Change your oil or else!" then rest easy, you're going to save some coin by not paying those idiots at the local version of "ACME LUBEGUYZ" to change your oil for you. (Besides... why pay someone else to forget to reinstall the oil plug when ya can do that yourself for free? *doh!*)

What you'll need

  1. As usual, a basic set of tools along with some shop towels and a big piece of cardboard to slide up under the XJ to catch any spillage.
  2. 6 quarts of quality oil. I prefer Havoline oil myself but the arguements are many for all the various brands.
  3. One word of caution regarding use of synthetic oil in an old engine ESPECIALLY 4.0L engines that are prone to rear main seal leaks
    Using synthetic is asking for trouble! Yes, some people use synthetic and swear by it... many more tried synthetic and swear AT it. If the engine has been running on synthetic - fine, keep using it. But if you are wanting to start using synthetic oil in a high milage engine that has used standard engine oil you'll end up with more oil leaking from the engine than before. It's up to you, but no way would I pay $6.50 a quart just to watch it dribble out onto the ground. (Go to Jeeps Unlimited and do a search for 'synthetic' and 'leaks' in the Cherokee forum. It's a real eye opener.)
  4. Use a good quality filter. K&N makes a great filter but they'll set ya back around $9 each. I'm using the NAPA brand WIX Gold filters, about $6.50.
  5. Since you're going to be changing your oil from now on (Right?) then score yourself one of those plastic oil drain containers that you drain the oil into and can cap off to take the oil in for recycling when you're through. WalMart has them for around $5.
  6. While you're at WalMart... grab a decent funnel with a 1/2" outlet hole. Smaller funnel holes will just fill up leaving you standing there all day while the oil drains out of the funnel.
  7. Either borrow or buy a good oil filter wrench from your local auto parts store since most filters require more effort to remove than they did to go on. For removing old filters, I like the 'strap' kind of filter wrench as opposed to the metal 'ring-clamp' style. The strap wrenches are nothing more than a loop of nylon strap attached to a length of square tubing that you can use a 1/2" drive ratchet on. The metal ring clamp style doesn't have much room to work on an XJ. Both wrap around the filter and depend on compression to grip the filter case enabling you to apply greater torque to remove a tight filter.

6 quarts QUALITY motor oil. Depending on engine's miles, some people run heavier oil in summer, lighter oil in winter. I usually run 10w-40 year round but now run Havoline URSA 15w-40. (Shown here). URSA is rated for diesel, equipment & hard usage engines. Also, it did not have those crappy 'wide mouth' tops that the Havoline marketing crackheads tried on all the other weights oil so you'll spill oil everywhere. Thankfully they've gone back to normal sized spouts. $8.03 inc. tax
1 QUALITY oil filter. K&N Gold or WIX Gold are good filters. (Ya get what ya pay for).Good quality filters will not allow the engine oil to drain from the filter and back into the engine. $7.00 +/- depending on choice.

Havoline URSA 15w-40 and NAPA WIX Gold filter.

until you can comfortably work with it!

Tech Tip: Disposable latex gloves are great for this job! Sure - you aren't going to be drinking this stuff but used motor oil is NOT good to get all over you.

Ok, you've got your cardboard laid out, a few rags or heavy shop towels handy, your oil drain pan is under the transmission ready to be pulled into position and the engine is warm, but NOT HOT! Locate the proper box wrench, or better yet, socket to EXACTLY fit your rig's drain plug. (I had already swapped my drain plug for a magnetic one so you need to determine your own drain plug's size).

Oil drain plug.
"Look ma! No rear main leak!"

Make sure the socket fits EXACTLY! It shouldn't be hard to remove but ya don't want to strip or round the head off! You shouldn't have to put a great deal of effort into removing the plug (unless some crackhead at a Lube Shop over did it...). Loosen, but don't remove the plug. Pull the drain pan up so that when the plug is removed, the oil will shoot out into it.

CAUTION! The oil WILL shoot out several inches away from the hole, nearly a foot in some cases so be prepared! Be prepared to handle a hot drain plug at the same time! Make sure your drain pan hole is too small for the plug in case you drop it and hang on to that sucker! (That's why the socket and not the box wrench. Sockets are good to keep it from shooting off into pan).

Loosening plug.

Like I said, oil is gonna shoot out across the entire pan at first, then slow to a trickle. Recenter the pan once it slows and then reaches a trickle. Let it drain while ya remove the filter.

"First thing ya know old Jeds a


Here's the filter. It's the white canister located on the passenger side of the 4.0L engine, just behind the motor mount and beside the distributor. Your motor mounts won't look like mine (with Rusty's sticker) unless they've been swapped. Also, various brands of oil filters come in different colors.

Most XJ filters are mounted up like this but some mount facing rearwards.

Here is a view of the filter with the strap style filter wrench on it and then an extension bar inserted into the wrench (extending up & out of picture at about 1 o'clock). If your filter won't come off easily, one of these wrenches makes quick work of it. Filter removes turning counter clockwise. Slip the old filter into an old plastic bag, or inside the new filter's box & dispose of in trash.

Strap it on!

Take your new filter and rub a little of the old oil onto the entire filter seal ring (black rubber ring on base surrounding center hole). This will help prevent the filter from sticking and being hard to remove next time. Install your new filter until it bottoms then tighten another 3/4 turn. Check filter box for manufacturer recommendations on tightening if you have any doubts.


Now for the two most important steps of the whole process...


These are the two steps that the ACME LUBEGUYZ places seem to have major problems with.

Unless your career goals include putting "IDIOT" on your resume don't leave these steps out!

Crawl back underneath and carefully replace the drain plug & washer. Tighten drain plug back down but DO NOT overtighten it! If you manage to strip out the threads (or they already were stripped) you can get replacement plugs with slightly oversized threads at the auto parts store. Remember, DO NOT OVERTIGHTEN the drain plug!

Carefully cap the oil drain pan and set aside to take to recycling center. Advance Auto and many other parts stores will accept used oil for recycling.


Wipe off the oil pan with a rag & crawl back out. Remove filler cap from valve cover and insert CLEAN funnel insuring that it will remain in place while pouring oil.

For a Jeep 4.0L 6 cylinder engine, carefully pour 6 quarts oil in. (5.9 quarts actually, since some oil remains in engine from previous oil but don't worry about the small extra amount).

5.9 quarts!

Replace filler cap and look back underneath for leaks/seepage from oil drain plug or filter. Verify oil level on dipstick.

Crank, but do not start engine. This is just to get some oil back up to the pump through the pickup tube.

Start engine while WATCHING OIL PRESSURE GUAGE. If you don't have a guage about all you can do is listen CAREFULLY to engine for ANY unusual sounds. (No guages? Fix that here!)

Your engine should QUICKLY build oil pressure and not make any unusual noises, rattles or knock!
If pressure is low or ANY unusual noise is present SHUT MOTOR OFF! Double check oil level. You would be amazed how many people forget to put oil back in the engine!

That's it! Clean up your mess and double check AGAIN for leaks!

Tech Tip: Install a magnetic drain plug when you change your oil. These plugs contain a magnet which catch small metal particulates in your oil that otherwise would circulate back into your engine doing damage. You only need to buy this one time and at under $5 they are cheap protection for your motor. Checking the plug each time you change oil helps you keep tabs on the wear rate of internal parts.

Magnetic oil drain plug.

Uh-oh. I screwed up!

  • On rare occasions, a filter will be so tight the filter canister crushes while trying to remove it. Don't panic if this happens! Just move the filter strap closer to the base of the filter canister and try again. In extreme cases, a screwdriver driven through the filter canister... just off-center of a terminally stuck filter will usually take care of it. You should get an experienced person to give ya a hand if things get that bad. On the other hand, once you've seen that done, you'll have no problems with a terminally stuck filter again. (I once RIPPED a filter in half trying the screwdriver trick... I think I used vice grips on the remains to get it started turning. Good reason NOT to over tighten your new one!)
  • If your drain plug is stripped, or you strip it out there are oversize plugs available at most auto parts stores to cover that mistake.

Now, take the coin you saved and go buy yerself a lollypop.

And don't forget to take the used oil to a recycling center!

If you have pics of your own repairs or can suggest other methods - please contribute your ideas (and pictures) to this article!

Revised on: October 31, 2006

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