The D110 uses a Kohler engine with a spin-on oil filter located on the side of the engine block

The John Deere D110 lawn tractor comes with a Kohler Courage engine, and the oil filter is the cylindrical cartridge you'll find mounted vertically on the engine's side. It's a spin-on style, meaning you twist it off by hand rather than unbolting a cartridge from a housing. The filter sits close to the engine block, so you'll need a bit of clearance to reach it comfortably — many owners find it easier to access from the right side of the mower when you're sitting in the operator's seat.

Knowing exactly where this filter sits matters because it affects how you'll drain the old oil and position yourself during the change. The D110's design puts the filter low enough that old oil will drip down, so you'll want a pan underneath before you loosen it.

Key Takeaways

  • The D110 takes a Kohler spin-on oil filter that you hand-tighten after coating the rubber gasket with fresh oil.
  • The correct filter part number is AM125424, which you can order from John Deere dealers or online equipment suppliers.
  • You should change the oil and filter together every 50 hours of mowing or once per season, whichever comes first.
  • The filter wrench makes removal easier if the filter is tight, but hand-removal works fine if you let the engine cool slightly first.

Finding the correct filter part number

The original equipment manufacturer (OEM) part number for the D110 oil filter is AM125424. This is the Kohler-branded filter that John Deere specifies for this model. You can order it directly from a John Deere dealer, or you can search for it by part number on equipment supplier websites — many online retailers stock it and ship quickly.

If you want to use an aftermarket filter instead, look for one that matches the same thread size and diameter as the AM125424. Common aftermarket equivalents include Fram PH8A and Kohler 12 050 01-S, but always verify the specifications match before purchasing. The filter should be roughly 3 inches tall and 2.75 inches in diameter.

How to remove and install the spin-on filter

Start with the engine cool and the mower parked on level ground. Locate the filter on the side of the engine block — it's the cylinder sticking out perpendicular to the engine. Position an oil drain pan underneath it to catch the oil that will spill when you loosen it.

Turn the filter counterclockwise by hand. If it's tight, wrap a filter wrench around it — a standard 3-inch oil filter wrench works well — and turn slowly. Once it breaks free, you can usually unscrew it the rest of the way by hand. Let the old filter drain into the pan for a minute or two before setting it aside.

Before installing the new filter, wipe the mounting surface on the engine block clean with a rag. Then coat the rubber gasket (the flat ring on the new filter's top) with a thin layer of fresh oil. This helps the gasket seal properly and makes removal easier next time. Screw the new filter on by hand until the gasket contacts the engine block, then turn it an additional three-quarter turn. Do not use a wrench to tighten it — hand-tight is correct.

Oil and filter change intervals for the D110

John Deere recommends changing the oil and filter together every 50 operating hours or once per season, whichever comes first. For most homeowners who mow weekly during the growing season, that means one change per year. If you use the mower heavily — say, for landscaping work or maintaining a large property — you may hit 50 hours before the season ends and need an earlier change.

The D110 holds approximately 2 quarts of oil. Use the oil grade specified in your owner's manual, which is typically SAE 10W-30 for year-round use in most climates. Check the oil level with the dipstick before each mowing session, and top it off if it's low — running low on oil can damage the engine.

Tools and supplies you'll need

You don't need much to change the filter yourself. Gather an oil drain pan (any container that holds at least 3 quarts), a filter wrench if the filter is stuck, a clean rag, and the replacement filter. Some owners also keep a small funnel handy, though it's not essential.

If you're changing the oil at the same time — which you should — you'll also need the correct oil type and amount, an oil drain plug wrench (usually a standard wrench that fits your D110's drain plug), and a way to dispose of the old oil. Many auto parts stores and service stations accept used oil for free, and some municipalities have collection days.

Common problems and how to avoid them

The most frequent issue is over-tightening the new filter. Hand-tight plus three-quarter turn is the right amount — tightening it more makes it nearly impossible to remove next time and can damage the gasket. If you've over-tightened it, let the engine cool and try again with a filter wrench, turning slowly and gently.

Another common mistake is forgetting to oil the gasket on the new filter. Skipping this step can cause the gasket to stick to the engine block, making removal difficult and potentially damaging the gasket. It takes five seconds and prevents frustration later.

If oil leaks from around the filter after installation, the gasket probably didn't seat properly. Stop the engine, let it cool, and check that the filter is tight. If it is, remove it, wipe the mounting surface clean, oil the new gasket, and reinstall it.

Where to buy replacement filters

John Deere dealers stock the AM125424 filter and can order it if they don't have it in stock. Expect to pay between $8 and $15 for the filter itself, depending on the dealer. Online equipment suppliers like Tractor Supply, Amazon, and specialty mower parts retailers also carry it, often at similar prices with the option of free shipping on larger orders.

Aftermarket filters are usually cheaper — sometimes $5 to $8 — but verify that the part number and specifications match before ordering. Reading customer reviews on the retailer's site can help you avoid filters that don't fit properly or fail early.

Frequently Asked Questions

Can I use a different oil filter on my D110?

Yes, as long as it has the same thread size, diameter, and height as the AM125424. Check the specifications on the filter packaging or the retailer's website. Using a filter that's too large or too small can cause fit problems or inadequate oil flow.

How often should I check the oil level between changes?

Check it before each mowing session, especially during the first few hours of a new filter or after an oil change. Once you're confident the level is stable, checking it weekly during the season is reasonable. Low oil can cause engine damage, so it's worth the 30 seconds.

What should I do with the old oil filter?

Most auto parts stores, service stations, and municipal hazardous waste facilities accept used oil filters for free. Some recycling centers also take them. Never throw an oil filter in the trash — it contains residual oil that contaminates soil and water.

Is the filter wrench necessary, or can I always remove it by hand?

Hand removal works fine if the filter isn't over-tightened and the engine is cool. A filter wrench is useful if the filter is stuck or if you have limited hand strength. They cost $5 to $15 and last for years, so many owners keep one in the garage.

What happens if I don't change the filter when I change the oil?

The old filter contains dirt and debris that will circulate through the new oil, reducing its effectiveness and shortening engine life. Always change the filter and oil together — the filter is inexpensive compared to engine repair.