Revisiting oil in manifold

bwilson4web · Dec 29, 2014

Nothing personal but I came across this article:

. . .
We thought maybe the Jeep needed a software flash update to the engine's computer, or maybe a rat had chewed through an engine harness while the SUV sat outside in these cold Chicago temps, as had happened to our Chevrolet Volt. The last thing we expected to hear was that our Cherokee was getting a new engine at only 13,300 miles. After all, the four-cylinder didn't spectacularly fail in a burst of shattered pistons and connecting rods leaving us stranded on the side of the road. We drove the Cherokee into the service bay under its own power, as it was operating fairly normally.

What the technician found there was surprising, though: excessive amounts of oil had crept into the intake side of the engine, coating the intake manifold, hoses and an engine management sensor.

We're not talking about a light coating of oil residue. Oil drained from the intake manifold partially filled a cereal-bowl-sized plastic dish. The Manifold Absolute Pressure sensor, a vacuum sensor mounted to the intake manifold that's used to communicate fueling information to the engine's computer, was also covered in oil, as were the insides of the engine's crankcase ventilation hoses. Our Cherokee's engine was approximately 2.5 quarts low from the manufacturer-required 5.5-quart capacity.
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Source: Why Jeep Replaced Our 2014 Cherokee's Engine - KickingTires

It certainly sounds like the Jeep service technicians have a different point of view.

Bob Wilson

mikefocke · Dec 29, 2014

Probably failure of a part that allows vapors from the crankcase to be recycled into the intake for burning in the combustion process. The part is supposed to separate and return oil droplets back to the crankcase.

The part used to be the PCV (Positive Crankcase Ventilation) valve and now can be called the AOS (Air Oil Separator).

When they fail, you can also get fouled catalytic converters from unburned oil getting into them so ask about those too. Likewise O2 sensors that sit in the exhaust system. And last but not least, the MAF (Mass Airflow Sensor) that sits in the intake-manifold/pipeing. Clean manifold, throttle body, see if any in the air filter. Check plugs condition. Most of this should be unnecessary with the new engine. But I'd ask for a warranty extension on the cats, MAF and O2 sensors if they aren't replaced as part of the process.

Revisiting oil in manifold

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Revisiting oil in manifold

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