DIY repair guide for 2013 Subaru Outback
How to Replace the Thermostat on a 2013 Subaru Outback
How to Replace the Thermostat on a 2013 Subaru Outback. The quick answer is below, then the longer procedure, parts, and factory references.
Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Quick answer
Start with the exact fitment check
This page keeps the thermostat replacement fitment, timing, and procedure notes close to the top so the vehicle stays in view while you work.
Direct answer
Confirm the repair data before ordering
Check the manual for your 2013 Subaru Outback to confirm that this procedure applies to its engine and configuration before ordering parts or starting work.
- • Difficulty: Easy to Intermediate
- • Time: 1-2 hours
- • Primary part: Thermostat
- • Work on cool engine
Before you order
Use the fitment checks already on this page
Thermostat jobs convert when the buyer can confirm housing style, gasket coverage, and coolant needs in one pass.
- • Confirm thermostat or housing style for your engine.
- • Check whether the gasket or seal is included.
- • Plan for the correct coolant and bleed procedure before opening the system.
Next step
Keep the exact vehicle hub open
The hub keeps repair, wiring, codes, and manual paths in the same context while you compare the next move.
- • Use the vehicle notes above for any exact-fit caveat before teardown.
- • Use the service notes on this page for torque and order of operations.
- • Use the linked manual if you need a factory reference for access or routing.
This vehicle's factory manual
2013 Subaru Outback: confirm the engine, trim, or drivetrain to open the available repair and diagnosis sections.
Exact-fit quick check
2013 Subaru Outback FB25: Lower-Hose Thermostat, 10mm Bolts at 8.7 ft-lb
Unlike the old EJ25, Subaru’s FB25 2.5L in the 2013 Outback mounts the thermostat at the water-pump inlet on the front of the block, fed by the lower radiator hose. The compact housing uses small 10mm bolts that strip easily in the aluminum block.
OEM thermostat: Subaru 21200-AA072 (170°F start-to-open, fully open at 194°F) or Gates 33970; the FB25 runs hotter than the EJ — never substitute a lower-temp racing stat
Housing: Two 10mm bolts into the aluminum water-pump body; torque to 8.7 ft-lb (105 in-lb) — the FB block threads are shallow and strip above 12 ft-lb
Gasket: Rubber O-ring built into the stat flange — lubricate with Subaru coolant conditioner or fresh Super Coolant before pressing into the bore
Coolant: Subaru Super Coolant (SOA868V9270) blue; capacity 7.7 quarts (7.3 liters); drain the radiator and the block petcock (12mm hex on passenger side) for complete removal
Access: The lower hose is directly behind the front subframe — jack the front and remove the plastic undertray (four 12mm bolts) for straight access to the housing
Pro tip: The FB25 has a bleed screw on top of the thermostat housing (cross-head) — crack it open during refill until steady coolant weeps out, then close it to purge air pockets that cause overheating
Warm-up check: After install, the temp needle should sit just below the halfway mark within 5 minutes of driving; if it climbs rapidly, air is trapped — re-bleed immediately
Exact-fit parts
Parts You'll Need
Vehicle-specific part numbers and quantities pulled from the factory service manual data for this repair.
170°F start; fits FB20 and FB25
Blue Super Coolant; pre-mix 50/50
Add one bottle during refill
Shop prep
Tools Required
Gather these exact sizes and tools before you start — the manual calls each one out for a reason.
Socket set
10mm · Housing bolts
Torque wrench
1/4-inch drive · Range 20–200 in-lb
Socket set
12mm · Undertray and block petcock
Screwdriver
Cross-head · Housing bleed screw
Safety-critical values
Torque Specifications
These are factory torque values from the OEM service manual. Overtightening can strip threads; undertightening can cause leaks or component failure.
| Component | Torque Value |
|---|---|
| Thermostat housing bolts (10mm) | 8.7 ft-lb (105 in-lb) |
| Block drain petcock | Hand tight |
Check the procedure for your vehicle
A year and model alone may not identify the correct repair. Match the engine, drivetrain and equipment to the service manual before using the overview below.
Match your vehicle
Check the VIN, engine and drivetrain against the manual. Different configurations can use different components and procedures.
Confirm the service details
Use the matching service procedure for access, fastener specifications and service sequence. General time and cost estimates do not establish applicability.
Manual and spec cross-checks
Use the linked manual and spec paths to verify fitment, torque, and service order before teardown.
Related Pages
More resources for this repair
Browse related vehicle pages, model guides, and other thermostat replacement resources.
Vehicle hub
2013 Subaru Outback Repair Hub
See all repairs, wiring diagrams, and codes for your 2013 Subaru Outback.
Model cluster
Subaru Outback Guides
Browse all repair guides for the Subaru Outback.
Repair family
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More Subaru Outback guides
Symptom routing
Priority symptom hubs that lead to this repair
These report-backed symptom hubs are the strongest plain-English entry points into this repair path, related codes, and exact vehicle troubleshooting.
Code reinforcement
Related Trouble Codes
These check engine light codes are often connected to this repair.
Cooling Code
P0116: Engine Coolant Temperature Sensor Range/Performance
Promote from symptom hubs and repair pages
Promote from symptom hubs and repair pages
Cooling Code
P0125: Insufficient Coolant Temperature for Closed Loop Fuel Control
Promote from symptom hubs and repair pages
Promote from symptom hubs and repair pages
Cooling Code
P0128: Coolant Thermostat Below Regulating Temperature
Promote from symptom hubs and repair pages
Promote from symptom hubs and repair pages
Cooling Code
P0217: Engine Coolant Over Temperature
Promote from symptom hubs and repair pages
Promote from symptom hubs and repair pages
Best first step for this repair
Compare thermostat kits
Thermostat jobs convert when the buyer can confirm housing style, gasket coverage, and coolant needs in one pass.
Confirm thermostat or housing style for your engine.
Check whether the gasket or seal is included.
Plan for the correct coolant and bleed procedure before opening the system.
Need the walkthrough?
Open thermostat guide with bleed notes
Use the full guide if you want the cooling-system sequence, bleed reminders, and access cautions before opening the housing.
No signup required. Loads only when requested for a faster first page view.
Start here with the short guide, then open the full version if you need more detail.
At a glance
The core information most people want before deciding whether to do this repair themselves.
DIY parts cost: $20-80
Difficulty
Easy to Intermediate
Time
1-2 hours
Parts
3 items
Compare costs
Get a vehicle-specific estimate
Safety Warnings
- •Work on cool engine
- •Note thermostat orientation
- •Bleed cooling system after
Tools required
Gather these before you start so the job flows cleanly once the vehicle is apart. Click any tool to shop it on Amazon.
Thermostat fitment, gasket, and coolant items
Thermostat jobs often need the thermostat, seal, and coolant together. Verify housing style and temperature rating before checkout.
We surface the most relevant part number, OEM reference, or spec we have for this job so you can compare listings with higher confidence.
Bundle everything
Shop the complete thermostat replacement kit
Pads, rotors, hardware, fluids, and tools — one search for the whole job.
Cooling-system items to lock in first
Start with the thermostat assembly, then add sealing and refill items so the car does not sit apart waiting on coolant.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
What the Pros Prefer: 2013 Subaru Outback Thermostat Replacement
Professional 4-step job flow, tool sizes, and certified technician best practices.
Job Preparation & Access Clearance
Shop Tip:Clear dust and road grime from the working area before loosening hardware. Protect eyes and hands from fluids and sharp metal edges.
Fastener Extraction & Component Disassembly
Shop Tip:Apply penetrating spray to heat-cycled or rusted bolts 10 minutes prior to removal. Use 6-point sockets to avoid rounding off bolt heads.
Mating Surface Inspection & Cleaning
Shop Tip:Clean all mounting surfaces to bare metal. Verify that old gaskets, O-rings, and crush washers are fully removed before installing new parts.
Final Torque & Operational Verification
Shop Tip:Torque fasteners to factory OEM specifications in an alternating star or criss-cross pattern to ensure uniform clamping pressure.
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Basic procedure overview
This is the short version of the job flow. The AI guide below fills in torque specs, access details, and vehicle-specific cautions.
- 1Drain some coolant
- 2Locate thermostat housing
- 3Remove housing bolts
- 4Remove old thermostat and gasket
- 5Clean mating surfaces
- 6Install new thermostat and refill
Frequently asked questions
- How much does thermostat replacement cost for a 2013 Subaru Outback?
- The general parts estimate shown here is $20-80. It is not a quote for your 2013 Subaru Outback's exact engine or configuration. Confirm the required parts and supplies in the matching manual, compare current prices, and get a written shop estimate that identifies the work and labor included.
- How long does thermostat replacement take on a 2013 Subaru Outback?
- A thermostat replacement on a 2013 Subaru Outback typically takes 1-2 hours for a DIY mechanic. Professional shops may be faster due to lifts and pneumatic tools. First-timers should add 30–60 minutes for setup and learning.
- Can I do thermostat replacement myself on a 2013 Subaru Outback?
- Difficulty varies depending on your 2013 Subaru Outback's specific configuration. With the right tools and a service manual, most handy owners can complete this in 1-2 hours.
- What tools do I need for thermostat replacement on a 2013 Subaru Outback?
- For thermostat replacement on a 2013 Subaru Outback you'll need: Drain pan, Socket set, Scraper, Torque wrench. You'll also need the correct replacement parts: Thermostat, Thermostat gasket, Coolant.
- What happens if I delay thermostat replacement on my 2013 Subaru Outback?
- A stuck thermostat causes your 2013 Subaru Outback to overheat (stuck closed) or run too cold (stuck open). Overheating risks serious engine damage; running cold increases fuel consumption and wear.
- Where is the thermostat on a 2013 Subaru Outback 2.5L?
- The 2013 Outback FB25 thermostat is in the lower radiator hose at the front of the block, behind the subframe. Two 10mm bolts torque to 8.7 ft-lb. Use Subaru 21200-AA072 or Gates 33970. Bleed via the screw on top of the housing.
Get the Full AI-Powered Repair Guide
Use the expanded guide alongside the service manual for your 2013 Subaru Outback. Confirm specifications, parts and procedure for your engine before starting.
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