PeachParts Mercedes-Benz Forum - View Single Post

jay_bob · #9 11-01-2017, 10:44 AM

I would consider the resistor bypasses to be a temporary solution not a permanent fix.

The swirl flap is important, it really affects engine performance. It is not just for emissions controls. The swirl flaps are moved based on engine rpm. The airflow through the intake manifold, especially once the air passes the divisions to each cylinder, is not constant, but intermittent. The swirl flaps are used to manage the pressure waves that can be set up in the intake runners as the intake valves open and close. The pressure waves can actually reduce the air flow coming into the cylinder. Remember that on a diesel engine, you are air limited, not fuel limited, so any restriction of air reduces the performance.

We had the swirl flap motor fail on our 2008 ML and after putting the resistor in the line to get the car running again, the performance and mileage really suffered, until I could fix it correctly. We lost easily 3-4 mpg with the swirl flap bypassed.

As for the coolant tank alarm, I will share this story on my 98 E300:
Got in the car a few weeks ago, the low coolant message was showing.
Looked under the hood to investigate, found a split in the upper radiator hose.
If that alarm had not shown I would have gotten down the road and would have gotten stranded. Or worse lost my coolant totally and baked the engine.

These systems are there for a reason.