Abstract: A housing, such as an air filter housing, with a plastic attachment tab is provided with a releasable, one-piece, U-shaped attachment clip engaging in a through aperture in the attachment tab and having sleeves formed in the vicinity of the through aperture on the inside of each leg of the U-shaped clip, and at least one resilient tongue on each leg of the clip pressing against the attachment tab.

Abstract: A one-way throttling valve for use in the vacuum line of a pneumatic membrane actuator which controls the combustion air temperature of a carburetor-euipped internal combustion engine by means of an air flow proportioning flapper admitting cold raw air and/or preheated raw air into a duct junction upstream of the intake filter, the throttling valve having a tiny throttling orifice which remains open, while the throttling valve itself is closed, thereby delaying the removal of negative pressure from the pneumatic actuator. The one-way throttling valve may be arranged in one of the two vacuum line connectors of the valve housing of a thermostat relief valve.