Jeep 4WD How-to: Winter Engine Oil Change with a New Mopar Oil
Oil and filter changes are a critical part of Jeep maintenance. Whether
your Jeep is new or has high mileage, premium oil and regular filter changes protect your investment. Use of
genuine Mopar filters will extend your
Jeep's service life and increase reliability.
For many climates, winter and summer are optimal times for oil change.
The magazine's XJ Cherokee spends summers in the Nevada desert and High Sierra heat. November through May, that
same region drops temperatures well below freezing for months. This calls for oil viscosity
The June 1st and November 1st oil changes include a switch in viscosity.
Sub-freezing late fall through spring, 5W-30 weight oil is the choice. June through October, protection means
10W-40 weight oil. Oil changes are never more than 5,000 miles apart, and each change includes a new
Mopar oil filter.
Following these steps, you can perform an oil change with minimal tools.
Change oil and filters regularly, following the guidelines in your glovebox Jeep Owners
Note: When driving extensively off-road, forget about
"mileage" between oil changes. Count the hours clocked on the engine. Adjust your oil and filter change intervals,
as you would with off-highway equipment.
1. Here is the oil drain plug on a 4.0L Jeep inline six-cylinder
engine. Other Jeep models are similar. This plug shows mild oil seepage, enough to stain your driveway and film
the under-carriage with oil over time.
2. The drain plug seepage blows back to the converter housing. This
easy-to-remedy oil leak is often mistaken for a rear main seal leak. There is a simple solution
3. Use a large
drain pan to avoid splash and spillage onto the shop floor or driveway. This inexpensive cement mixing trough
works well and has lasted several years.
4. Warm oil will drain more completely, taking contaminants with it.
Avoid scorching yourself with hot oil! Drain the oil warm and wear nitrile gloves to
prevent exposure to hazardous drain oil.
5. Warm 10W-40 weight oil runs out of the crankcase like water! Make sure
you pull the drain plug away slowly from the last thread to avoid uncontrolled spillage. Keep the drain pan
centered to allow for an arc of oil flow.
6. This handy platform, acquired years ago, easily attaches to the
33" tire. Adjustable to various light truck tire sizes, the platform is ideal for lifted Jeep 4x4s and
trucks with tall fenders and deep engine bays. This makes oil changes, tune-ups and engine work
7. Use a filter cap tool and a
flex-handled rachet for safe oil filter removal. If you do not over-tighten the filter, it will come loose later
with reasonable force. This notched filter wrench fits snugly at the end of the filter
8. Make sure the drain pan is beneath the oil filter. Horizontally
mounted filters will pour out oil as soon as the filter loosens. Spin out the filter just a few threads. Let
oil drain into the pan before removing the filter.
9. Filter drained, you can unthread the filter completely from the engine
adapter. On horizontal mounts like this one, point the loosened filter toward the drain pan and let out the
10. Empty old oil filter is now lifted straight up and out of the engine bay. On
many models, the filter removal is from the bottom of the engine. For this XJ Cherokee 4.0L inline six, lifting
upward is easier. Make certain that the old filter gasket comes off the filter mount.
Wipe old oil from the filter mount with a clean, lint-free rag.
11. This oil drain plug has been leaking slightly, enough to stain the driveway
between oil changes. The built-in rubber gasket is flattened badly.
12. Plug at right shows flattened gasket and metal-on-metal contact at the
sealing face. This plug cannot seal, no matter how tight the torque on it. A new Mopar plug (at left),
available through Jeep dealerships, will remedy a nuisance oil leak.
13. New plug must not be over-torqued. Setting for this 4.0L inline six is 25
ft-lbs. Make sure threads are clean before installing the plug. Torque to specification, allow to set for a moment,
then check torque again.
Caution: Once all oil has drained, install the
drain plug. Never finger tighten the drain plug with the intention of coming back to it. When you thread the drain
plug into place, immediately torque the plug to specification.
14. Generic oil filters often fit a variety of engine
applications, without matching the oil flow specifications for your engine. Genuine Mopar
oil filters will have the correct pressure drop across the filter, the right factory by-pass
valve relief setting and the proper micron filtration.
Note: Use the correct Mopar filter, by part number,
for your Jeep engine. See your local Jeep dealership.
15. The filter's installation instructions are on the canister. Follow these
instructions. Do not allow debris to fall into the open, clean filter. Make sure the new gasket is in place. Be sure the old filter gasket is not stuck to the engine
16. Put a film of clean motor
oil around the gasket face. If the filter mounts vertically or at least faces upward, fill it with fresh oil.
Horizontally mounted filters can be partially filled before installation. A half-fill works on this XJ
Cherokee 4.0L inline six application.
Pre-filling the filter with fresh, clean oil will reduce the time to fill the new filter when the engine starts.
The highest wear to crankshaft bearings occurs during engine start-up. Oil change start-ups are
even greater risk to bearings. Minimize wear by pre-priming the filter. Oil pressure will pick up quicker,
helping to preserve your engine's bearings.
17. New Mopar oil filter is
carefully threaded onto the engine adapter threads. Keep all surfaces clean. Start the threads carefully. Partially
filled with oil, keep the horizontally-mounted 4.0L oil filter upright as long as possible. Prompt
installation will help avoid oil spillage from the new filter.
18. If the filter is difficult
to reach and tighten, use the filter end cap
wrench and a ratchet. Snug up the filter to the amount described on the filter canister or
packaging. Do not over-tighten the new filter or damage the canister. Center the tool and tighten the
Note: Nobody wants a filter to leak
or come loose in service! Normal tightening is by hand and not excessive. This enables removal later without a
problem...A typical Jeep oil filter recommendation is to thread the filter onto the adapter by hand until the
filter gasket contacts the stand—then turn the filter one full turn beyond this point.
Suggestion: I tighten the filter by
the specified method (one-turn or whatever recommended on the oil filter canister). Beyond that, I perform a
"two-hands-snug" test to confirm that the filter is secure...In my experience, the "two-hands-snug" (past the minimum "one-turn" or recommended point)
is a better approach, reducing risk of a false setting and nuisance leak—or worse...Always
check for leaks after start-up!—Moses
19. If you can grip the
filter comfortably, tighten it securely by hand. One strong hand at the end of a smaller filter is adequate for
this 4.0L inline six installation.
Note: A two-hands grip at the sides
of the filter canister works well when the filter's end is awkward to reach or difficult to
20. New Mopar oil filter
is now secured by hand. The XJ Cherokee is notorious for dirty drain oil pouring over the low-hanging wire
looms and suspension parts. Wipe off any drainage spills before running the engine. Check for leaks
21. Wipe away debris and
remove the oil fill cap. Most modern caps are threaded with an O-ring or gasket seal. They have a torque
sensitive "rachet" mechanism to avoid risk of over-tightening. Wipe the cap clean.
22. A large capacity oil
fill can with spout and lever-stopper can handle a full crankcase of oil. Place the can on a solid and stable base,
steady enough to not fall over when weighty oil fills up the can! 4.0L inline six has a crankcase capacity
of six quarts (U.S.) with the new oil filter installed.
Flex spout on oil can allows filling the engine without risk of spillage. Once
oil drains completely into the engine, the spout can be easily bent
upward from the valve cover opening, avoiding spillage and
24. Use a high quality
motor oil. Mopar offers both oil and filters. Our '05 Ram-Cummins engine uses Mopar MaxPro® 15W-40 diesel formula motor oil. For the XJ Cherokee 4.0L six
(shown), this fill is for winter, using 5W-30 weight Chevron Supreme 'Iso-Syn' formulated oil. For
summer months, the switch is to 10W-40 weight oil.
25. Clean and install the
cap carefully. This cap rachets when secure, preventing risk of over-tightening. As indicated on the cap, you can
find the recommended oil type and viscosity listed in the Owners Manual.
26. Check the engine oil
level before start-up. On the 4.0L engine, six U.S. quarts will fill the crankcase and new Mopar oil filter. On the
dipstick, the level reads over-full prior to the engine startup. Once the engine starts, the oil filter will fill
completely and drop the dipstick reading.
27. Start and run the
engine at an idle. With a primed oil filter, oil pressure should come up quickly. Allow the engine oil to circulate
completely for a few minutes while checking for oil leaks at the filter and drain plug. Shut off the engine.
Allow oil to drain fully into the crankcase (five minutes or so). On flat ground, re-check the oil level on the
dipstick and adjust the oil level to the full line if necessary. Do not overfill.
Your oil and filter change is now
28. A crankcase of dirty
motor oil is now in the drain pan. At our shop, this oil goes into a storage tank then gets transferred
via five-gallon pails to a disposal station for motor oil. Handle oil with nitrile mechanic's
Quick Underhood Spot Checks: Avoid the Perils of
critical of winter needs is a good battery. Nothing saps a battery more than a low state-of-charge and cold-weather
cranking. A battery that seems fine during the summer often fails completely in severe cold weather! Have
your battery load-tested prior to cold weather driving. Be sure the drive belt(s) and coolant hoses are
For us, winter typically means isolated highways, sub-freezing weather,
ice and snow buildup on roads—plus extreme wind and poor visibility. When we venture into winter driving,
whether on-highway or off-pavement, our Jeep 4WD is ready.
In the modern era of self-service fueling stations, it is up to owners to
spot check the underhood fluid levels between routine service intervals. Whether you sublet your routine service or
not, underhood spot checks can ward off trouble...and winter is certainly no time for
While underhood with your oil and filter change, make a quick spot
check. This is not a substitute for the full-service talked about in the "Jeep 4WD Lube-Oil-and-Filter
Service" or "Routine Service for Late
Jeep 4WD Models" articles. (See these two articles for details.) Here, we're addressing just
the obvious underhood spot checks and trouble areas...
Windshield washer performance can be
vital to visibility on a slushy, iced highway or muddy gravel road. Make sure the wiper fluid has adequate
anti-freeze protection—to at least minus-20 degrees F.
Power steering is a safety item. The
power pump reservoir is accessible with an easy to read dipstick. Keep this area clean and do not introduce dirt or
lint into the reservoir. Use Mopar power steering fluid only.
Brakes are always essential! Fortunately,
you can see the fluid level within modern clear plastic reservoirs without removing the cap. Make sure the vehicle
is on level ground. This cylinder is tilted, giving the impression of low fluid. Check when level and do not
overfill. Use recommended Mopar brake fluid.
The automatic transmission dipstick and
fill tube are accessible under the hood. The stick indicates proper fluid level and describes which position the
shifter should be set before checking fluid. Temperature is also a factor. Use only the Mopar ATF recommended for
your specific model and year of automatic transmission.
Anti-freeze/coolant is also critical in the
winter. Keep to at least -34 degrees F protection year round. This is a 50/50 mixture with traditional anti-freeze
(not pre-mixed). Always check anti-freeze with the engine cold, at the radiator filler cap. True radiator
protection is read at the radiator.
Warning: Check the radiator and cooling system with the engine cold! Never remove the
radiator cap while the engine is hot.
The coolant recovery tank should also be
good for -34 degrees F protection (same as the radiator). A common mistake is to add coolant or water to the
recovery tank without maintaining the -34 degrees F protection. Coolant, over time, mixes thoroughly between the
tank and radiator. If uncertain whether fluid has mixed thoroughly, check both the radiator and recovery tank with
your anti-freeze hydrometer.
Warning: Check the
radiator and cooling system with the engine cold! Never remove the radiator cap while the engine is