THINK TWICE

The 2AZ-FE's cylinder-head bolts thread directly into the aluminum block, and those threads strip or pull out. 33 federal complaints across these windows -- most on the 2004-2007 Highlander, where it is the engine's signature failure -- describe head-bolt threads stripping, head bolts pulling out, a resulting head-gasket leak, coolant loss (sometimes into the cylinders) and overheating. Owners are typically told the only fix is a new or rebuilt engine, often just outside warranty. The complaints skew four-cylinder wherever cylinder count is recorded, so this is the 2.4L four's failure, not the V6's.

Check — On a cold engine check the coolant level and condition, look for unexplained coolant loss with no external leak, white or sweet-smelling exhaust, and any history of overheating or head-gasket work. A documented head-bolt/thread or head-gasket repair (or engine replacement) is reassuring; unexplained coolant loss or overheating on a 2.4L example is a walk-away.

The one specific flag on the early port-injected 2GR-FE V6 is the VVT-i oil supply hose. Its rubber section hardens and cracks with age and can weep or, worse, rupture -- dumping engine oil in minutes. Owners describe the oil-pressure light and abnormal engine noise, an oil trail "for miles" behind the car, and a dipstick gone bone dry. 279 federal ENGINE complaints across the 2007-2011 Camry V6, 2008-2013 Highlander, 2007-2012 Sienna, 2007-2012 Avalon and 2007-2012 Lexus RX350 name an oil line or hose or the VVT actuator, and 85 explicitly call out the rubber hose. Many go on to engine damage after the oil loss (rod knock, seizure, a replaced engine), and roughly seventy report smoke or fire as hot oil hit the exhaust. Caught at the warning light it is a cheap hose; missed, it can cost the engine.

Check — On any early 2GR-FE car, inspect the VVT-i oil hose for a weeping or hardened rubber section and confirm the oil-pressure warning light works. Treat a sudden oil-pressure light, a knock, or a large oil puddle as stop-driving-now. Ask whether the updated hose has been fitted (see the service-campaign fact).