Toyota 3S (3S-FE / 3S-GE / 3S-GTE)

Toyota's 2.0 four — in the Camry, Celica, MR2 and the first RAV4, and the engine behind the Celica GT-Four's rally career.

Three suffixes, three engines. The 3S-FE is the economy version in the Camry and base Celica; the 3S-GE is the twin-cam sports head; and the 3S-GTE is turbocharged, in the GT-Four and the MR2 Turbo. They share a block and very little else, and almost everything written about the 3S's character is about the GTE — which does not describe the FE in a Camry beyond the bottom end.

On the naturally aspirated engines the recurring faults are peripheral. The distributor O-ring hardens and leaks oil into the distributor, producing misfires that read as ignition faults because they are, and the valve cover gasket follows. High-mileage FEs lose head gaskets, usually after being allowed to run hot.

On the GTE, the early turbochargers used a ceramic turbine wheel. It is lighter and spools faster, and it can shatter — after which the debris goes through the exhaust and, if the engine keeps running, damage spreads. A GTE with an unknown turbocharger history is worth establishing the vintage of, because the later steel wheels do not do this.