Change Your Tractor’s Oil Yourself

As a regular part of your farm’s equipment-maintenance routine, follow these steps to perform a tractor oil change and save yourself a trip to the service shop.

by Brian Landrum
PHOTO: istock/

As spring and summer gain momentum, it’s important to give a little love back to the tools and machines used so heavily when things are green and growing. Changing the oil in your tractor is one of the simplest ways to avoid major mechanical repairs to your machine’s motor.

A tractor oil change should be performed according to the hours specified in your machine’s owner’s manual or at least every six months. Even if the machine isn’t used heavily, one of the main goals of an oil change is to remove contaminants from the motor. Moisture is a contaminant that builds in the motor whether it is used or not, sometimes more so when the tractor spends a lot of time sitting in a barn.

Although an oil change is something any farm equipment service shop is willing and able to handle, for the hobby farmer who’d like to bypass a day hauling that machine into the shop or waiting on a service call list, an oil change is a great way to build confidence in machine maintenance. If you’re up to the task, here are a few tips and steps to help.

Step 1: Identify Your Machine’s Specifications

A service manual is ideal for this, but most basic owner’s manuals should give you the information you need. If not, contact a local farm-supply store or brand dealership. Here’s what you need to find out:

  • Does the tractor run on gasoline or diesel fuel? This will determine the type of oil to use. Because diesel motors run hotter and with higher compression, they require a specialized, heavier-duty oil.
  • What is the motor’s oil capacity? This is the number of quarts or liters it holds.
  • What is the recommended “weight”? Look for number labels such as 30W, 15W40, 20W50, et cetera.
  • What size and type of oil filter fits the machine? There are two main types of oil filters: spin-on and cartridge. Spin-on filters are usually exposed on the motor and thread on and off as one contained unit. Cartridge filters are inserted into a larger cover or chamber that must be removed and cleaned during the oil change.

Step 2: Drain the Oil

To minimize trips to the local farm-supply store, I like to start draining the oil and remove the filter before making a run for supplies. Park the tractor on a level, stable surface. Turn off the engine, set the parking brake and wedge the tires. Remove the keys from the ignition before getting started.

Using the service or owner’s manual, find the tractor’s oil drain plug; this is typically a large-headed bolt on the bottom of the engine block. Locate the correct wrench size (metric or standard, I like using a 12-point wrench end) and an adequate drain pan to catch the used oil. Before things get oily, I recommend slipping on a decent pair of nitrile safety gloves to help minimize any damage or irritation to your skin. With a shop towel handy, loosen the drain plug by turning counterclockwise, breaking it loose with the wrench and unthreading it the rest of the way by hand. Wipe the plug clean, and check for an O-ring or an aluminum or copper crush washer that helps seal the plug against engine block or drain pan. You’ll want to replace this sealer—and the plug itself, if needed—so take it with you when you get your supplies.

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Step 3: Remove the Filter

As the oil drains, have another adequate drain pan ready and locate the oil filter. If it’s a spin-on, use any commercially available oil filter wrench, whether it’s one that slips over the filter or a plier-style wrench, to break the filter loose. A cartridge filter is typically housed in a canister bolted onto the motor, so use the correct wrench or socket to remove the canister.

With a shop towel handy, remove the filter, paying attention to any o-rings or rubber gaskets that might be present; these will be replaced. The spin-on filter typically has one sealing O-ring on its mating surface that should come off with the filter; if it doesn’t, peel it off the motor. Installing a new filter without removing the old O-ring causes “double-gasketing” and the filter is likely to leak.

The cartridge filter can have one or more O-rings, depending on the style. Many times, the O-rings are located on housing assembly. A spring and spring-seat washer might also be present to hold the filter in place. Remove the sealing bolt(s) and the cartridge filter itself to locate any pieces, noting the order in which they come apart. Replacement O-rings should come with the new filter; springs and spring-seat washers are typically reused unless damaged or lost.

Step 4: Collect Supplies

As the oil drains, pick up supplies from a farm store or dealership, using the specs collected in step 1. You’ll need:

  • new oil
  • a new filter
  • a new drain plug crush washer or rubber gasket
  • possibly a new plug

This might also be a nice time to pick up any other related supplies, such as a funnel, shop towels, degreaser or brake-parts cleaner (for a quick clean up), and maybe even extra oil and filters for future oil changes.

Step 5: Reinstall the Oil Filter

Once back on the farm, you’ll reinstall the oil filter as it came apart, coating all O-rings or rubber gaskets with fresh oil first. Some motors—usually diesel motors with large, vertically installed filters—call for “priming” the oil filter before reinstallion: This simply means filling the filter assembly with new oil before it goes back on.

Thread spin-on filters by hand until they seat against the motor, then give another quarter to half turn until nice and snug. The filter needs to be tight but not wrenched on. Heat from motor use will expand the assembly and tighten the seal over time, and if it’s wrenched on from the beginning, it will be a bear to remove at the next oil change.

Reassemble the cartridge filters unit as it came apart, then bolt the assembly back on, keeping the bolt(s) snug but, again, not hammered on. If you have a torque wrench and a service manual with torque specs, now’s a great time to use them. If not, a good rule of thumb is to seat the bolt well, then add about one-eighth of a turn.

Step 6: Tighten the Drain Plug

With the filter installed, fix your new crush washer or O-ring on the drain plug and thread it in by hand until it seats. Again, tighten it down either by torque spec (recommended) or by the same rule of thumb used with the filter bolts. No matter how you finally tighten the plug, I would insist on starting it—or any threaded fastener—by hand to prevent cross-threading, which ruins both male and female bolt threads, and often seems to be the main culprit of oil change complications and headaches.

Step 7: Dispose of Old Oil

Once the filter and plug are installed and tight, wipe down and degrease your work surfaces. Remove your drain pans, emptying the used oil into a safe and adequate container to be recycled. Most service shops will accept your used oil for recycling, as long as your containers are safe and the amounts are reasonable.

Step 8: Refill with New Oil

Locate your oil fill, which is usually near your tractor’s oil level check dipstick and is sometimes the same. Using a funnel, fill the motor with the specified type, weight and amount of oil (for example: 5 quarts of Rotella 15W40 diesel oil), taking note of whether the amount includes the oil held by the filter. Tighten the oil fill cap and/or dipstick.

Step 9: Check for Leaks

With the transmission in neutral and the parking brake on, start and run the tractor at idle for at least 30 seconds, visually checking for leaks around the oil filter and drain plug. After confirming no leaks, shut down the motor and wait a few minutes, then check the oil level on the dipstick. If your specs are right, the level should be right on or at least close, though you might need to add or remove a small amount. When the level on the dipstick is correct, your oil change is done.

Although the first time or two may take a while, oil changes will become quick and easy as you do them more often. With oil changes under your belt, you might decide to try your hand at larger maintenance projects, keeping that tractor running smoothly for many years to come.

Get more tractor help with these articles:

  • 5 Seasonal Tractor Maintenance Tasks
  • 7 Daily Tractor Maintenance Tasks
  • Can You Afford That Tool?
  • Video: Tractor Buyer’s Guide


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