Checks, in order
- Level with the engine coldCheck the reservoir against the min and max marks only when the engine is cold. If it is low, note by how much.easy $ · under about $50
- Look under the truckLook for drips or crusty residue at hoses, the radiator and the water pump area. Take photos for the dealer.easy $ · under about $50
- Check the fansWith the A/C on and the truck warm at idle, the radiator fans should run. A fan that never runs is a fault to report.easy $ · under about $50
- Do not top off with random coolantUse only the type the manual specifies. Mixing types can cause problems, and the dealer will want to see the level as you found it.easy $ · under about $50
- Dealer pressure testA pressure test finds slow leaks. On a new truck this is a warranty repair.hard $$$ · shop-level job, $500+
Applies to: 6th generation 4Runner, 2025 and newer, with the 2.4L turbocharged i-FORCE and the i-FORCE MAX hybrid, both with the 8-speed automatic. This is a new platform with little long-term history, so most entries are general symptoms; when the truck is under warranty, the dealer is the right first stop.
Tools and parts for these checks
Links below are Amazon affiliate links: as an Amazon Associate, toyotadata earns from qualifying purchases, at no extra cost to you. Confirm fitment for your exact truck before you order.
| ITEM | USED FOR | BUY |
|---|---|---|
| Cooling system pressure tester | Finding coolant leaks and testing the radiator cap | Shop on Amazon |
| Toyota Super Long Life Coolant (50/50 premix) | Topping off or refilling with the factory-type coolant | Shop on Amazon |
| Infrared thermometer | Checking radiator, hose and thermostat temperatures | Shop on Amazon |
| Combustion leak (block) test kit | Checking coolant for exhaust gas from a head gasket | Shop on Amazon |
Go deeper
The same problem on other Toyotas
More 6th Gen 4Runner problems
- Something is wrong on a new 4Runner: warranty, recalls and where to start (Body & Electrical)
- Digital gauge cluster blank, missing speedometer, or warning lights not showing at startup (Body & Electrical)
- Clunk or abrupt shift, especially 1st to 2nd, or hesitation pulling away (Transmission)
- Front brakes squealing or chirping on a new truck (Brakes)
- Hybrid won't go to READY, or dead 12 V battery in the i-FORCE MAX (Hybrid System)
- Won't start or crank on the 2.4L turbo (non-hybrid) (Starting & Charging)
All 14 6th Gen 4Runner symptoms in the interactive troubleshooter →
General guidance from owner experience. Confirm torque specs, fluid capacities and procedures in the factory service manual. Brakes, steering and anything structural: if in doubt, have a qualified shop inspect it before driving.