Fix It

The PCV, or positive crankcase ventilation valve, on the 3.0-liter engine in your Ford Taurus requires attention from time to time. As the valve gets old, it will allow oil and vapors from inside the engine to leak out. The PCV system removes excess pressure and unburned gases from inside the engine, recirculating the gases through the engine to be burned and expelled out of the exhaust. This decreases the emissions from the tailpipe and allows your car to run cleaner.

Instructions

1

Open the hood of your Taurus and locate the PCV valve on the top of the valve cover. The PCV valve looks like an L-shaped fitting plugged into the top of the valve cover and has a large hose attached to it.

2

Grasp the PCV valve and pull it straight out of the valve cover grommet. Grasp the hose on the end of the valve and separate it from the valve. Lay the hose aside for now.

3

Discard the old PCV valve, then insert the end of the new valve into the end of the rubber vacuum hose that you removed from the old valve. You may need to twist it a little to get it to slide in place.

4

Push the new PCV valve into the grommet on the top of the valve cover. Make sure it seats completely in the grommet so oil does not blow past it. Close the hood.

Valve lifters are the actuators that open and close the valves on top of the engine, allowing the appropriate quantity of air into the cylinder. As with most moving parts under strain inside an engine; dirt, heat and friction take their toll over time, and the lifter will become worn, degrading its performance, and increasing the possibility of damaging other components.

Instructions

1

Remove the intake manifold and valve covers. Set them aside and take note of how all the bolts were positioned. Looking down into the engine, you should now be able to see the heads of the valves. But the push-rod will be passing over the top, preventing you from removing them.

2

Remove the rocker arms and push-rods. With all the upper hardware on the engine disassembled, the cylinder head can be unbolted and lifted off the rest of the engine, giving you access to the tappets below. With the tappets released and removed, the lifters are accessible and ready to be removed.

3

Grip the heads of the lifters with the needle-nose pliers and caully lift them up and out of their respective recesses. Lower the new lifters into the hole and replace the tappets. The tightness of the tappets is a trial and error process for mechanics who lack professional measuring equipment, so you may need to adjust them after the engine has been rebuilt. If the engine runs roughly, they need to be loosened. If they make a tapping noise, they need to be tightened.

4

Replace the push-rods, rocker arms, valve covers and intake manifold, ensuring all bolts are properly tightened. Start the engine and allow it to run for five minutes, then stop it and make the necessary tappet adjustments. Repeat until the engine is running smoothly, allowing it to cool for several minutes between each run.

The standard layout for automotive PCV (positive crankcase ventilation) valves was developed when rear-wheel-drive vehicles were the only kind on the road. The PCV concept became common in all internal combustion engines, including those in front-wheel-drive cars. The 2000 Chevrolet Lumina is a front-wheel drive vehicle with a sideways ("transverse mounted") engine. The emissions control system in the Lumina engine is basically the same as in other cars, but the PCV valve is placed in a different location than on other vehicles. Locating the PCV valve on a 2000 Chevrolet Lumina takes just a few minutes and no tools.

Instructions

1

Remove the engine cover, if one is present. Disconnect the oil filler tube by grasping it firmly and rotating it counterclockwise. The tube will lift out at that point, and the cover will pull right off.

2

Disconnect the vacuum tubing from the PCV valve on the 3.1-liter engine. The PCV valve is positioned on the passengers side of the engine along the back firewall. You will notice the tubing connecting to the top rear corner of the valve cover. That is the vacuum tubing. The PCV valve pops out when pulled. Inspect the unit and replace as necessary.

3

Disconnect the MAP sensor on the 3.8-liter engine to access the PCV valve. The sensor is positioned to the left of the spark plug wires just in front of the alternator as you look at the engine. The MAP sensor sits on top of the PCV cover. Unclip the sensor. Twist the cover about 1/8-turn and pull it free. The PCV valve sits in the housing and just pulls out. Remove and inspect the unit. Replace as necessary. Installation is the reverse of removal.

An EGR valve is a factory sealed unit, so it cannot be re-manufactured, but the problems associated with a failing EGR valve can be solved by replacing the unit. The EGR valve (exhaust gas recirculation valve) is usually found near the exhaust manifold but can also be found elsewhere on transverse engines. The purpose of an EGR valve is to burn exhaust gases a second time to aid in emissions and help fuel economy. When defective, an EGR valve causes poor acceleration and rough idle. A defective EGR valve often makes a flutter noise.

Instructions

1

Locate the EGR valve. A schematic of the car engine is a great help in locating the EGR valve.The EGR valve looks like a small round can with a small hat on top. A digital EGR valve will have a wire loom connected to it; a manual EGR valve will have vacuum lines connected to it. The base plate of the EGR valve, which is on the intake manifold, is connected to a small metal tube that runs to the exhaust manifold. The EGR valve is easiest to locate by tracing all lines, other than the exhaust pipes that connect to the exhaust manifold. The EGR valve may also may be connected to the EGR solinoid.

2

Remove all parts that obstruct access to the two EGR base plate bolts. Unplug the metal tubes, any vacuum lines and electric connections to the EGR valve.

3

Remove the bolts that hold the EGR valve to the base plate. These bolts are usually 1/2 inch or 12 mm.

4

Install a new factory-sealed EGR gasket. Replace the valve gasket, using gasket sealer prior to re-installation. Torque the bolts to manufacturers specs (approximately 11 to 16 foot pounds).

5

Working in reverse, reconnect all tubes, lines and electrical connections. Replace all other items that were removed to reach the EGR valve.

Power valves on Holley carburetors are usually trouble free, but they do occasionally require replacement. Engine modifications may dictate the use of a different power valve. You may want to change your power valve if youve moved to an area that is significantly higher or lower in elevation than your previous residence. Also, power valves may rupture and require replacement if the engine backfires through the carburetor. There usually no need to remove the carburetor from the engine in order to replace the power valve.

Instructions

1

Remove the fuel line from the carburetors fuel bowl. Fuel line attachments vary. The most typical style is a slip-on fitting with a hose clamp. Use a screwdriver to loosen the hose clamp, and pull the hose from the carburetor. Use a rag to soak up any spilled fuel.

2

Remove the fuel bowl from the carburetor. Remove the four hex head bolts that retain the fuel bowl and metering block using the 5/16-inch nut driver. Using the handle of the screwdriver, tap lightly on the fuel bowl to loosen it, and set the fuel bowl aside.

3

Remove the metering block to expose the power valve. Again, tap gently on the metering block to free it from the carburetor main body.

4

Unscrew the power valve from the metering block using a 1-inch wrench.

5

Install a gasket on the new power valve, and thread the valve into the metering block. Tighten hand-tight plus 1/8 turn.

6

Using new gaskets, reassemble the carburetor. Attach the power valve side of the metering block to the main body, followed by the fuel bowl. Insert the fuel bowl bolts into the fuel bowl, and tighten the bolts finger tight plus 1/4 turn.

7

Reattach the fuel line to the inlet on the fuel bowl, and tighten the hose clamp.

A hydraulic valve lifter lets the valve train ride on a cushion of oil, and automatically adjusts the valve clearance to compensate for changes in engine temperatures. Dirt and sludge build up over time, and the lifter parts gradually wear out. When the vehicle sits for a time, such as overnight, the oil inside the lifters leaks out. When you start the vehicle, the valves tap and rattle until the oil pressure builds up. Removing the valve lifters requires the disassembly of major engine components and caul attention to details.

Instructions

1

Remove the air cleaner, carburetor or throttle body injector, fuel lines and linkages. Remove any vacuum lines or electrical connectors attached to the intake manifold. Label all wires or vacuum hoses to ensure they can be put back into their original locations later. Place a shop rag over the exposed intake manifold where the carburetor or throttle body was removed. Ensure no dirt or other items fall into the intake manifold.

2

Remove the valve covers and set them aside. Loosen the valve adjuster lock nuts and turn the adjuster screws counterclockwise on all valves. The valve rockers should be loose enough to rotate sideways using only your fingers.

3

Drain the radiator coolant into a drain pan. Remove the intake manifold bolts and lift the intake manifold off the engine. Clean any residual gasket material or dirt off the mating surfaces of the manifold and cylinder heads using a scraper or putty knife and shop rags. Use caution and work caully to ensure no dirt or gasket material falls into the exposed engine or cylinder head intake ports.

4

Rotate the valve rocker arms to the side and remove the push rods. Arrange the push rods in order of removal to ensure they can be replaced in exactly the same position later. Remove the valve lifters from the bore using a strong magnet. Organize the lifters in the same way as the push rods, keeping them in order.

5

Inspect the bottom of the lifters for excessive wear. A lifter that is scratched or gouged indicates a worn out camshaft that should be replaced.

Efficient valve stem seals play an important role in the use of oil in a vehicles engine. When not working properly, faulty valve stem seals may cause a variety of problems.

Basics

Valve stem seals control the amount of oil lubrication that is provided to the valve train and ultimately the combustion chamber. This process is crucial for maintaining engine health and productivity.

Function

A valve stem seal has a lip that helps control the amount of oil on it as it maneuvers by continually wiping away the excess. At the same time, the seal allows oil to move past it and lubricate the valve guides. Multiple factors in the engines environment contribute to the amount of oil that is needed at any given time.

Problems

If a valve stem seal begins to fail, either too much or too little oil is allowed past the seal and multiple problems may arise. With limited oil flow, engines may experience problems with overheating or spark plug issues. When too much oil passes through the valve there may be an increase in hydrocarbon emissions, as well as damage to the catalytic converter. In addition, debris from old seals may clog oil passages.