2019 Subaru Impreza Oil Change — FB20D, 4.2 Qt 0W-20, 31 ft-lb Drain Plug

I've done the oil change on the 2019 Impreza and it's one of the more accessible Subaru jobs — the horizontally opposed (boxer) engine sits lower and wider than most four-cylinders, which actually makes filter and drain access easy once you know where to look. The capacity is tight at 4.2 quarts, so precision matters. Here's exactly how I do it.

Overview

The 2019 Subaru Impreza uses the FB20D naturally aspirated 2.0L boxer four-cylinder, shared with the Crosstrek 2.0L and base Forester.

• Oil capacity: 4.2 qt (3.98L) with filter change
• Oil spec: 0W-20 full synthetic (API SN or SP)
• Drain plug: 17mm hex, 31 ft-lb (42 Nm)
• Filter: Subaru 15208AA15A (OEM) or Wix 57055, Mobil 1 M1-110

Subaru's recommended interval: 6,000 miles / 6 months severe; 7,500 miles normal. I do 5,000 miles personally.

Tools & Parts Needed

Item	Spec / Part Number
Oil capacity	4.2 qt (with filter)
Oil spec	0W-20 full synthetic
Oil filter (OEM)	Subaru 15208AA15A
Oil filter (aftermarket)	Wix 57055, Mobil 1 M1-110
Drain plug size	17mm hex
Drain plug torque	31 ft-lb (42 Nm)
Filter torque	14 ft-lb (19 Nm) — hand tight + 3/4 turn
Drain plug washer	Subaru 803916060 (aluminum crush washer)

Step-by-Step Instructions

1. Warm the Oil

Run engine 3–4 minutes. Warm oil drains faster. Don't let it run fully hot.

2. Lift and Access

The 2019 Impreza sits low — ramps or a floor jack work well. Remove the front undertray (10mm bolts or plastic push-pins) to access the drain plug and filter.

3. Drain the Oil

Position drain pan under the drain plug on the driver's side of the oil pan. 17mm hex. Break loose counterclockwise, remove by hand with slight upward pressure. Drain 5–8 minutes.

Crush washer: The FB20D uses an aluminum crush washer (Subaru 803916060). Single-use — replace every time. A box of 10 costs about $8.

4. Remove the Oil Filter

Filter on the passenger side of the engine, angled down and forward. 65mm cap-style wrench if tight. Pre-oil new filter gasket. Confirm old gasket came off with old filter.

5. Reinstall Drain Plug and Filter

New crush washer on the plug, thread in by hand, torque to 31 ft-lb (42 Nm). Install filter hand-tight until gasket contacts, then 3/4 turn (14 ft-lb / 19 Nm).

6. Add Oil

Lower vehicle. Add 4.0 quarts 0W-20. Start for 30 seconds, shut off, wait 2 minutes, check dipstick. Top off to FULL mark in small increments. The FB20D has a narrow operating range on the dipstick.

7. Reset Oil Life Monitor

Navigate to vehicle info screen, find "Oil Life," hold OK to reset.

Common Mistakes

Overfilling the FB20D. The 4.2-quart capacity is genuinely smaller than most engines. Many people instinctively pour 4.5 or 5 quarts, see the dipstick low after startup, add more, and end up overfilling. An overfilled crankcase causes the crankshaft to churn through oil (aeration), leading to foaming and reduced lubrication. Add 4.0 quarts, start, check dipstick, then top off to exact FULL. The final 0.1–0.2 quart makes the difference.

Pro Tips

• Idemitsu 0W-20 is OEM-spec and typically 10–15% cheaper than Subaru branded oil at the same quality.
• The FB20D shares its filter (15208AA15A) with the 2019 Crosstrek 2.0L and 2018 Forester 2.5L — buy in bulk for multiple Subarus.
• Inspect drain plug threads at each service. Repeated over-torquing from shop air guns strips these threads.

Save Money with OwnerDrop

A quick lube shop charges $60–$90 for a 0W-20 full synthetic oil change. DIY costs $30–$40. That's $30–$60 saved every interval.

For related Subaru maintenance, the 2020 Subaru Forester oil change guide covers the FB25 2.5L boxer with the same drain plug torque. The 2020 Subaru Outback oil change covers CVT fluid monitoring as well.

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