OIL LEAKS

COMMON CONCERNS: A Burnt Smell On The Drive Home, Fresh Oil Spots Where You Park, Oil Level Down Between Changes.

Those leaks are often one of two seals, one around the valve cover and one where the oil filter housing bolts on. Both sit at nearly the same height, so both drop oil onto the parts below. Heat cycling hardens the rubber until it stops sealing.

From underneath the two look identical, so we clean the engine, run it, and watch where oil appears. The accessory belt runs below both seals. A soaked belt turns a gasket job into a longer one, so the belt gets checked too. We replace the seal that is leaking, then inspect the neighboring seal and the belt for oil damage before recommending anything else.

COOLING SYSTEM

COMMON CONCERNS: A Wet Patch Under The Engine, A Sweet Smell After Parking, A Temperature Warning In Traffic.

A sweet smell after you park is coolant landing on something hot. On these engines the coolant tank, the thermostat housing and the hose fittings are plastic, and the water pump is electric. Plastic that's been heated and cooled for years turns brittle, and a brittle seam splits.

We pressure-test the system cold first. The point where it loses pressure is usually a seam or a fitting. Then we log coolant temperature as the engine warms, which shows whether the thermostat is opening. A leak at the tank seam is a contained repair, and the system holds level again.

IGNITION AND MISFIRE

COMMON CONCERNS: A Rough Idle At A Stoplight, A Hesitation Pulling Away, A Flashing Engine Light.

The coil and the plug on each cylinder are both wear items on a turbocharged engine. As a plug wears the gap gets wider, and a wider gap takes more voltage to jump. A worn coil can't supply that voltage.

We pull the freeze-frame data and misfire counts to find the cylinder. Because each coil lifts off on its own, we can swap the suspect one onto another cylinder and re-read the counts. If the count moves to the new cylinder, that coil is the failed part, and we'll replace only that one. Fuel goes straight to the cylinder on these engines, so carbon collects on the intake valves and a marginal system feels worse.

CHARGE PIPE AND LOST BOOST

COMMON CONCERNS: A Sudden Drop In Power, A Rush Of Air Under Throttle, Low Power Until You Restart.

The turbocharger pushes compressed air to the engine through a pipe, and part of that path is plastic that heat and pressure make brittle at the coupling. It cracks, or the coupling pops off under throttle, so air escapes before it reaches the cylinders. The engine then makes a fraction of its usual power until you restart.

This fault only appears under load, so the road test runs with the throttle open. We log the boost the engine makes on that pull, and a low figure points at the charge path. A cracked pipe and a loose coupling feel identical from the seat. We hold that side under pressure on the lift and find where it escapes.

FRONT SUSPENSION AND STEERING FEEL

COMMON CONCERNS: A Shimmy In The Wheel At Highway Speed, Vague Steering, A Knock Over Rough Pavement.

The front control arms hold the wheel through rubber bushings that keep the ride quiet. As those bushings soften and split, the wheel gets room to move on its own. You feel it most on the freeway. Most of these cars wear run-flat tires, and stiff sidewalls pass more road into the same bushings.

We load each arm on the lift and watch for movement. A road test separates a suspension shimmy from a brake pulse, since a pulse appears under braking and a shimmy at speed. Fresh bushings bring back the steering that made you buy the car.