The 2023 Volkswagen Jetta features the brand’s latest generation EA211 1.5-liter turbocharged four cylinder gasoline engine, here with 158 horsepower and 184 pound-feet of torque. In our Jetta test vehicle it has an 8-speed automatic transmission and is rated by the EPA at 29 mpg city, 40 mpg highway, and 33 mpg combined.
The all-aluminum engine features a fuel saving Budack Cycle combustion regime alone with dual variable cam timing, and a relatively high compression ratio for a turbocharged engine at 11.5:1. It’s variable geometry turbocharger features an electronically controlled waste gate and fuel is fed via a high-pressure direct injection system.
Following the airflow, the intake charge starts behind the grille and enters a large air filter box at the front of the engine bay. From there it travels through a plastic tube to the rear of the engine to the turbocharger.
Once boosted, the air travels back to the front of the engine where its temperature is lowered with an air-to-water intercooler attached directly to the plastic composite intake manifold. This arrangement reduces the plumbing associated with air-to-air intercoolers and is said to reduce turbo lag as a result.
From there the air is sent into the engine and combustion takes place. Atop the head you can see the four spark plug coil packs. The fuel direct fuel injection system is for the most part not visible as it resides underneath various other components out of sight. Once the air passes through the head into the combustion chambers, it then exits through the turbocharger at the rear of the engine and out to the catalyst and exhaust system.
As complicated as it all may sound, the VW Jetta has one of the most straightforward and simply laid out engine bays among contemporary vehicles.
The engine coolant reservoir is located on the passenger side of the engine compartment above the wheel well, its level clearly visible and easily managed. Checking the oil level is done nearby at the passenger side front of the engine at the bright yellow dipstick handle. The oil filler cap is located adjacent to it at the top of the engine. The oil filter itself is located the bottom of the engine.
The air filter box is at the front of the engine bay on the driver side and requires tools to change the filter. Next to it is the blue cap for the windshield washer fluid reservoir noted by its bright blue cap.
Checking and filling the brake fluid is done at the driver side rear of the engine bay. To the right of the brake fluid reservoir is the 12V battery – nicely wrapped in an insulation jacket. Next to it is the main engine control unit (ECU).
The main fuse block is located at the far driver side above the wheel well, accessed by popping a couple clips. An included fuse removal tool can be found inside.
Other items of note include the ABS brake system controller located at the passenger side firewall, not really a service or maintenance item. At the front of the engine you will find a single serpentine accessory drive belt for the alternator and air-conditioner.
The water pump is electrically powered and at the front of the engine bay you will find an electric fan cooling the radiator. Keep hands clear even when the engine is turned off.