Mechanic Checklist: Timing Belts, Water Pumps & Transmissions on Used Cars

Buying a used vehicle with 100,000 to 150,000 miles on the odometer is one of the smartest financial decisions a Maine driver can make — if you know what to verify before the sale. In this mileage range, most major mechanical systems are mature and battle-tested, but a handful of critical maintenance milestones either have or haven’t been completed. Missing them after purchase can cost anywhere from $800 to $3,500 in repair bills. This checklist covers every item Porter inspects on every vehicle at It Runs Well Car Company before it goes on sale.

Timing Belts vs. Timing Chains — The Most Important Distinction
The timing belt or chain synchronizes the rotation of the crankshaft and camshafts, ensuring that intake and exhaust valves open and close at precisely the right moment relative to piston travel. When a timing belt fails, the engine typically suffers catastrophic internal damage — bent valves, damaged pistons, or a destroyed cylinder head — resulting in repair bills that exceed the value of most used vehicles in the sub-$10,000 range. Timing chains are made of steel and last the life of the engine when properly lubricated with regular oil changes. Timing belts are made of reinforced rubber and must be replaced at specified mileage intervals regardless of appearance. Knowing which your target vehicle has is the first question to answer. Browse our current inventory — every listing includes engine specifications and known service history.

Honda 3.5L V6 — The Critical Timing Belt Engine
The Honda J35 3.5-liter V6 engine powers the Odyssey minivan (2005–2017), Pilot (2003–2015), and Ridgeline. It is one of the most reliable V6 engines ever built — but it uses a rubber timing belt with a factory replacement interval of 105,000 miles. The service includes the belt, tensioner, and idler pulleys, and critically, the water pump (which is driven by the timing belt). The total service cost at an independent mechanic ranges from $700 to $1,100 depending on labor rates. If you are evaluating a used Honda Odyssey or Pilot, the first question to ask is: has the timing belt been replaced, and at what mileage? Request written documentation — a dealer stamp in the service book, a mechanic’s receipt, or a CarFax service record. If there is no documentation and the vehicle has more than 100,000 miles, assume the belt has not been done and factor $900 into your offer price negotiation or walk away from the asking price.

Toyota 2.5L and 3.5L Engines — Timing Chain, No Belt Worries
Toyota’s 2AR-FE 2.5L four-cylinder (Camry 2010–2017, RAV4 2013–2018) and 2GR-FE 3.5L V6 (Sienna, Highlander, Avalon) both use steel timing chains that require no scheduled replacement. This is a significant ownership advantage and one of the reasons Toyota Camrys and Siennas command a price premium in the used market. For a high-mileage Toyota Camry with 130,000 miles, the timing system is genuinely not a concern as long as regular oil changes have been maintained. What you do need to check on high-mileage Toyotas: engine oil consumption (add a quart between changes on some 2.5L engines), condition of the VVT-i oil control valves (inexpensive to replace but causes rough idle if fouled), and catalytic converter health on California-emission vehicles.

Subaru 2.5L — Head Gaskets Are the Priority Check
The EJ25 2.5L four-cylinder engine in the Subaru Forester, Outback, and Impreza (through 2012) has a documented history of external head gasket seepage. This is well-known in the Subaru community and does not make these vehicles bad — it makes proper inspection essential. External head gasket failure presents as: oil seepage along the cylinder head-to-block mating surface (visible as brown or black residue on the sides of the engine), coolant seepage in the same area (visible as white crystalline deposits), or a slow coolant level drop without visible external leak. Internal head gasket failure (combustion gases mixing with coolant) is more serious and shows as: white smoke from the exhaust, milky residue inside the oil cap, or an overheating engine. Porter pressure-tests the cooling system and conducts a combustion gas test on every used Subaru AWD vehicle before listing. Post-2012 Subaru models with the FB25 engine have significantly improved head gasket design.

Automatic Transmission — The Questions to Ask
Automatic transmission fluid degrades over time and mileage, and unlike engine oil, many manufacturers specify it as a ‘lifetime fill’ — a claim that independent mechanics largely reject. Transmission fluid should be inspected and typically exchanged every 30,000 to 60,000 miles in real-world salt-belt driving. Pull the transmission dipstick (if accessible) and check the fluid color and smell: fresh fluid is bright red and slightly sweet-smelling. Dark brown or black fluid with a burnt smell indicates degraded fluid that has been contaminated with friction material from clutch packs. This doesn’t necessarily mean the transmission is failing, but it means it’s been neglected. A transmission fluid drain and fill (not a full flush, which can actually dislodge debris) costs $120 to $180 at an independent shop. During the test drive, listen and feel for: delayed engagement when shifting from Park to Drive, slipping between gears on acceleration, harsh or clunking shifts, or any hesitation when downshifting for passing. Any of these symptoms warrants a dedicated transmission inspection before purchase. If you’re unsure, contact Porter for a pre-purchase assessment.

Brakes — What Good and Bad Look Like
Brake pads and rotors are consumable items, but their condition tells you a lot about how a vehicle has been driven and maintained. With the wheels off, you can see the brake pad thickness through the caliper. Pads have a minimum thickness of about 2-3mm — anything thinner needs immediate replacement. More importantly, look at the rotor surface: a smooth, uniformly grey surface is healthy. Deep concentric grooves indicate worn pads that have been running metal-on-metal. Blue discoloration indicates the brakes have been repeatedly overheated — a sign of aggressive driving or extended hill descents. In a Maine salt-belt vehicle, also check the caliper slide pins and brackets for seizure caused by corrosion. A seized caliper causes uneven pad wear and pulling under braking. Budget $300 to $600 for a complete front or rear brake service if needed, and use it as a negotiating point.

The Pre-Purchase Inspection — When to Get One
For any used vehicle purchase over $4,000, spending $100 to $150 on a pre-purchase inspection at an independent mechanic is money extremely well spent. A lift inspection combined with a code scan and test drive takes about an hour and identifies the items above plus cooling system pressure, exhaust integrity, steering rack condition, and any stored fault codes. If a private seller refuses to allow a pre-purchase inspection, treat that as a significant red flag. At It Runs Well Car Company, Porter’s listings have already undergone this process — the mechanical inspection is done before pricing, not after. Tell Porter what you’re looking for and he’ll source a vehicle that has already passed every item on this checklist.