This AI-generated draft has not been independently verified for your vehicle. Confirm engine, trim, build date, tool fitment and torque specifications against the relevant service information before buying tools or starting work.
On the 10th-gen Accord the thermostat is not in the upper hose where many people look for it. All three powertrains put it in a housing on the lower front of the block where the lower radiator hose lands, so the job is really a coolant drain plus dropping the plastic under-tray, then two small bolts. Tool-wise it is cheap: 10 mm and 12 mm sockets, a couple of extensions, hose clamp pliers and a funnel kit.
What varies is access. The 1.5T gives the most room, the 2.0T has more plumbing in the way, and the hybrid demands you disable the high-voltage system first and know that its electric coolant pump can cause the same symptoms as a bad thermostat. The mistake people make is the refill — these engines trap air readily, and skipping a proper burp with a spill-free funnel and two fan cycles leads to an overheat scare on the first drive and a false conclusion that the new thermostat is bad.
| Item | Type | Product search |
|---|---|---|
| Floor jack 2 ton minimum, low-profile Lifts the front of the car to reach the under-tray and lower hose. | Required | search retailer |
| Jack stands 2 ton pair, under front subframe jack points Supports the car while you work underneath. | Safety | search retailer |
| Wheel chocks Blocks the rear wheels with the car nose-up. | Safety | search retailer |
| Socket set 10 mm and 12 mm, 3/8 in drive, 6-point 10 mm for the under-tray and splash shields, 10/12 mm for thermostat housing bolts depending on engine. | Required | search retailer |
| Ratchet and extensions 3/8 in drive, 3 in and 6 in extensions plus swivel Reaches the housing bolts tucked behind the lower hose. | Required | search retailer |
| Trim clip / panel removal tool Plastic pry set Pops the plastic fir-tree clips holding the engine under-tray and splash shield. | Required | search retailer |
| Drain pan 6 qt / 6 L minimum, wide Catches coolant from the radiator drain and the lower hose. | Required | search retailer |
| Hose clamp pliers Spring-band clamp pliers, cable type preferred Releases the lower radiator hose clamp at the thermostat housing in tight quarters. | Required | search retailer |
| Flat screwdriver Medium, long shaft Opens the plastic radiator drain plug and breaks the hose loose from the housing neck. | Required | search retailer |
| Pick or hose removal tool 90-degree pick Frees a stuck hose from the housing without cutting it. | Recommended | search retailer |
| Gasket scraper Plastic or brass, non-marring Cleans the aluminum housing face without gouging it. | Recommended | search retailer |
| Torque wrench 1/4 or 3/8 in drive, 5-25 ft-lb range Small M6/M8 bolts into aluminum strip easily if guessed. | Required | search retailer |
| Funnel kit Spill-free funnel with Honda/universal radiator neck adapter Fills and burps the system without airlocks — essential on these engines. | Required | search retailer |
| Coolant tester or refractometer Confirms mix strength if you dilute concentrate or top up. | Recommended | search retailer |
| OBD-II scan tool Live-data capable, reads ECT Watch coolant temp and fan operation while burping; clears any P0128/P0217 codes. | Recommended | search retailer |
| Thermostat with gasket Honda 19301-5A2-A02 style assembly for 1.5T/2.0T; confirm by VIN — hybrid uses its own part The replacement unit; Honda sells it as a thermostat with integral rubber seal. | Parts | search retailer |
| Thermostat housing gasket / O-ring Included with OEM thermostat; buy separately for aftermarket Sealing the cover to the block; never reuse the old rubber. | Parts | search retailer |
| Honda Type 2 coolant Blue, pre-mixed, 2 gallons for a full flush; 1 gallon for drain-and-fill Honda-specific silicate-free formula; do not substitute green or universal orange. | Consumables | search retailer |
| Distilled water 1 gallon Rinse and top-up only; never tap water. | Consumables | search retailer |
| Nitrile gloves and eye protection Coolant is a skin and eye irritant and the system may still be hot. | Safety | search retailer |
| Insulated HV gloves Class 0, 1000 V — hybrid only Required precaution before touching anything near orange cabling on the hybrid. | Safety | search retailer |
| Shop towels and parts cleaner Brake or general purpose cleaner Cleans the sealing face and mops up spilled coolant. | Consumables | search retailer |
1.5T (L15BE) and 2.0T (K20C4) both use a block-mounted housing with two bolts, most commonly 10 mm heads on M6 fasteners; some 2.0T housings use 12 mm heads, so carry both. The hybrid's 2.0 Atkinson (LFA) uses the same tooling but a different thermostat part number and requires the high-voltage service disconnect procedure before you start. Under-tray fasteners are 10 mm on all trims, with more plastic clips on Sport and Touring aero trays.
| Thermostat housing / cover bolts (M6, 10 mm head) | 9.8 Nm (7.2 ft-lb) — verify in the service manual for your engine |
| Thermostat housing bolts if M8, 12 mm head | 22 Nm (16 ft-lb) — verify in the service manual |
| Radiator drain plug (plastic) | Hand-snug only, do not use a tool to tighten — verify in the service manual |
| Engine under-tray bolts (10 mm) | 9 Nm (7 ft-lb) — verify in the service manual |
| Hybrid high-voltage service plug cover bolts | verify in the service manual |
It is in a housing bolted to the lower front of the engine block, on the side where the lower radiator hose connects — not in the upper hose. You reach it from underneath after removing the plastic engine under-tray.
A radiator drain gives up roughly 3-4 quarts, so one gallon of pre-mixed Honda Type 2 blue coolant is enough for a drain-and-fill. Budget two gallons if you plan to flush the whole system.
Most 10th-gen Accords use two M6 bolts with 10 mm heads; some 2.0T housings use 12 mm heads. Have both sockets plus a 3 in and 6 in extension and torque to spec — they go into aluminum.
Yes — a stuck-open thermostat commonly triggers P0128 (coolant temp below thermostat regulating temperature), often with slow warm-up and weak heat. Confirm with live ECT data, since low coolant or a faulty sensor produce the same code.