Chevrolet 12643296 Hose, Pcv

High temperatures under the hood can cause deterioration of rubber and plastic hoses used for engine, accessory, and emission systems operation, necessitating periodic inspection for cracks, loose clamps, material hardening, and leaks. Most hoses are secured with clamps, which should be checked for tension to prevent leaks; if clamps are absent, ensure the hose has not expanded or hardened at the fitting. To reduce hydrocarbon emissions, crankcase blow-by gas is vented through the PCV valve to the intake manifold via a rubber hose, which should be inspected for cracks and obstructions. Vacuum hoses, often color-coded, require attention to wall thickness and material when replacing, and should be completely removed for effective inspection, including any plastic T-fittings. A small piece of vacuum hose can be used to detect leaks by listening for hissing sounds. Fuel lines, usually under pressure, should be checked for deterioration, especially at bends and fittings, and only hoses designed for the specific fuel injection system should be used for replacements. Spring-type clamps on fuel lines may lose tension and should be replaced with screw clamps, while metal lines must be inspected for bends or cracks, and any replacements should use seamless steel tubing. Additionally, metal brake lines should be checked for cracks and loose fittings, with any brake fluid leakage requiring immediate inspection of the brake system.

The Positive Crankcase Ventilation (PCV) system is a very important in minimizing hydrocarbon emission by evacuation of crankcase full of unburned hydrocarbon fumes. On a four cylinders the system comprises a single crankcase ventilation hose that sucks in crankcase vapors through the vent housing installed on the under part of the valve cover and then channeling the vapors into the air intake duct before entering the combustion chambers. For V6 models, there is a fixed orifice on the front valve cover; two hoses control the air fresh and crankcase vapor with regard to intake manifold vacuum. Deterioration of PCV system is not good for the engine; therefore, one should check the hoses for the crack or any obstruction and to clean or replace as the case may be. Approxations of both of these problems may include a rough idle as well as stalling, or the presence of oil leaks, and in interpretation of a leakage sign, there may be rough running or high idle speed. A functional check on V6 models involves a removal of the end of PCV hose, the starting of the engine and checking for vacuum. In case of a higher crankcase pressure that is above the expected limit then it is advised to be checked by an expert. In cases of heavy sludge or oil dilution, more tests are required. In case of component exchange, it requires removal of hoses and conditioning or replacement of vent housing, fixed orifice, however, vent housing is molded in the valve cover and cannot be replaced independently.