GMC 6484966 Breather Assembly, Air Cleaner & Silencer

The PCV system on every Century vehicle functions to handle vapors from crankcase blow-by. The running engine allows gases from the combustion chamber to leak through the piston rings into the crankcase which generates pressure that affects both engine oil quality and causes atmospheric pollution unless appropriate management solutions are used. These crankcase emission control components redirect gas vapors they collect into the combustion chamber for complete combustion again. Undefiled air generates entry into the crankcase before the combustion gases attach then pass through the oil separator and PCV valve towards the induction system where they become part of the combustion chamber. The PCV valve functions as the key component which regulates gas movement by monitoring engine speed together with throttle position. A disrupted valve will create excessive pressure that produces oil leakage and sludge development. Inspection of PCV valves should include testing for idle vacuum while you also need to replace the valve every 30,000 miles. The PCV valve installation requires correct insertion along with secure attachment while you should examine related system components for damage. The process of installation begins with air cleaner removal followed by grommet and coupling inspection after which comes new filter insertion before completing the installation by ensuring proper connection security.

Engineering for both Centurys and Regals include positive crank-case ventilation (PCV) system to control emissions of blow-by vapours from the crank-case. When the engine is running, there are some gases which escape from the combustion chamber to the crank case through piston ring. These pressurised gases can be emitted to the atmosphere, they may cause contaminations in the engine oil and formation of sludge. The PCV system recirculates these gases back into the combustion chamber by drawing clean filtered air through the air filter into the crank case where it collects combustion gases then passes through oil separator and PCV valve and into the induction system. The PCV valve is rather important as it controls the gas flow; it restricts the flow of the gases at low rpm but unlocks the path further at higher rpm. The problems arise when the valve is blocked and the gas forces its way through weak seals where it leads to formation of oil leaks and sludges. The PCV valve needs vacuum at idle and the hoses and connections of the system need to be inspected and replaced. The valve should be taken out and shaken, and if it does not produce a rattling sound, there is probability it is blocked and has to be changed. When replacing the PCV valve, certain type should be used to prevent some driveability problems. During installation or reassembly be sure that the valve has been put in the correct place and securely clamped down, and check related parts for signs of wear before reinstalling the air cleaner and connections.

Replace the PCV valve every 30,000 miles (48,000 km). The breather filter, located in the air cleaner on equipped models, is replaced when the air cleaner element is replaced. For V6 engines, the PCV valve is located in the right-hand valve cover on 1975-80 models. On 1981-87 models, the PCV valve is located in the rear of the intake manifold. For V8 engines, the PCV valve is located in one of the valve covers depending on the engine. To remove and install, pull the PCV valve and hose straight out of the valve cover or manifold. Use a pair of pliers to slide the hose clamp, if equipped back down the hose and off the valve connector. Twist the valve gently to loosen it from the hose, then remove. Inspect the hose and valve cover grommet, and replace if they are hard, brittle or cracked. Clean the hose with solvent if it is clogged. Install the valve into the hose, making sure it seats fully in the hose. Attach the hose clamp, if equipped around the valve assembly. Install the PCV valve in the grommet, making sure the valve seats fully in the cover grommet.

The PCV valve is usually found in a rocker arm cover, connected to a hose leading to the carburetor or intake manifold. When replacing, ensure the new valve matches your vehicle and engine size. To replace, remove the valve from its rubber grommet in the cover, loosen the hose clamp, and remove the valve from the hose. Compare the old and new valves for identicality.

The PCV valve can be found on the rocker cover because of its running tube to the carburetor. Ensure that you purchase a substitute for the vehicle, engine size, and model year. It has to be removed by pulling the valve with hose still intact through its rubber grommet from rocker arm cover and then remove PCV valve from the hose while noting its position and direction of installation. Before installing it you must compare your new PCV valve with old one to see if they are similar. Push it entirely until seated properly to the end of the hose. If there are imperfections on this grommet, it should be changed with a new one.

The PCV system should be checked at every oil change and serviced every 30,000 miles (48,000 km).

The PCV valve is typically found in the rocker arm cover.

The hose connected to the PCV valve runs to either the carburetor or the intake manifold.

Check the rubber grommet for any damage and replace it if necessary, before pushing the PCV valve and hose back into the rocker arm cover.

To replace the PCV valve, first, pull the valve (with the hose attached) from the rubber grommet in the rocker arm cover or manifold. Then, loosen the retaining clamp and remove the PCV valve from the end of the hose, taking note of its installed position and direction. Compare the old valve with the new one to ensure that they are the same. Push the new valve into the end of the hose until it is properly seated, and then reinstall the clamp. Inspect the rubber grommet for any damage and replace it with a new one if necessary. Finally, securely push the PCV valve and hose into position.