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How-to » Engine » Mechanical, Lubrication & Cooling » How to Perform a Valve Job
 Note: This is a general guide and may not apply to your vehicle.

How to Perform a Valve Job

for the 2000 Subaru Outback Limited 4 Cyl 2.5L change
PARTS
  • Exhaust Valve
  • Intake Valve
  • 1 more part
TOOLS
  • Screwdriver
  • Standard Hammer
  • 1 more tool
STEPS
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Hard
Safety Tip:
Always wear safety glasses when working on your vehicle. Wear other personal protective equipment (PPE) when necessary, for example latex gloves or closed toe shoes.

1
Open the hood and make sure it is properly secured
2
Locate the vehicle's battery and disconnect the negative battery cable from the battery post.
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3
Remove the lower radiator hose.
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4
Drain the cooling system.
5
Remove the air filter and air intake system.
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6
Disconnect all rubber vacuum hoses.
7
Disconnect all linkages or cables that may be routed on top of the engine. This will allow easier component access and free up space.
8
Locate the vehicle intake manifold.
9
After locating the intake manifold, remove any hoses, pipes or linkages that will be attached the intake manifold.
10
After removing the intake manifold accessories, locate and loosen all the intake manifold mounting bolts. Remove the intake manifold.
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11
After removing the intake manifold, clean out any dirt, debris or gaskets.
12
Gain access to the valve covers.
13
Remove the valve covers.
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14
Unbolt the exhaust manifold from the vehicle.
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15
Gain access to the vehicle cylinder head.
16
Removal of the cylinder head bolts will require following a manufacturer recommended sequence.
17
Lift the cylinder head from the engine block carefully. Do not damage, scratch or score the cylinder head bottom surface.
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18
Once the cylinder head is removed follow the steps below to perform the valve job:

The head is steam cleaned, disassembled and inspected.



Cast iron heads are checked for cracks by being magnafluxed. This process uses a magnetic field and iron powder to make cracks more visible.



The head is inspected for straightness with a straight edge and feeler gauge. If excessive warpage is present you will need to have the head resurfaced or replaced.



Next, the valve guides, seats and valves themselves are inspected. Typically the valve guides are worn and will need to be replaced or knurled. This process resizes the valve guides to the correct bore size.



The valve seats are usually ground to resurface them and restore the sealing surface. Seats can also be punched out and replaced if too badly worn.



The valves are inspected for wear such as bending, overheating and cracking. If they are good and can be reused, the seats will be ground to match the new sealing surface of the valve seats.



The valve springs, rocker arms, push rods, and lifters are all inspected to make sure all parts are reusable and do not need replacement.
19
Re-install the cylinder head and accompanying parts in the reverse order.
20
Refill radiator with a 50/50 mix of coolant and distilled water.
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21
Fill overflow reservoir with same mixture.
22
Leave the radiator cap off, start engine and let it idle. You should see the system burping (bubbles of air coming up). Refill the radiator to the top.
23
Install the radiator cap.
24
Check the engine oil level and top off if needed.
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25
Road test the vehicle, keep an eye on the engine temperature gauge if vehicle runs hot. There still may be air pockets in the cooling system. The cooling system should be topped off after the vehicle has fully cooled down.
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