What You Need to Know Before Starting
Replacing a camshaft is a mid-level engine repair that requires removing the cylinder head and timing components. You will need a full set of hand tools, a torque wrench, a gasket scraper, new gaskets and seals, and an engine hoist or jack rated for your vehicle's weight. The job takes 8 to 16 hours depending on your engine layout and whether you have done it before.
Before you begin, check your vehicle's service manual for the exact torque specifications, bolt removal sequence, and timing marks for your specific make and model. Camshaft replacement is not a task where approximation works — incorrect reassembly can bend valves or damage the engine. If you are not confident in your ability to follow a detailed sequence and use a torque wrench correctly, this repair is better left to a shop.
The cost of parts alone (camshaft, gaskets, seals, and often a timing chain or belt) ranges widely by vehicle, but expect $200 to $800 in parts. Labor at a shop typically runs $1,000 to $2,500. Doing it yourself saves the labor cost but requires time, a clean workspace, and the right tools.
Key Takeaways
- You must remove the cylinder head, drain the coolant, and disconnect the fuel system and electrical connectors before touching the camshaft.
- Mark or photograph the timing marks on the crankshaft and camshaft before removing the timing chain or belt, or you will not be able to reassemble the engine correctly.
- The camshaft bolts must be removed in the sequence specified in your service manual, not at random, or the cylinder head can warp.
- New gaskets, seals, and often a new timing chain or belt must be installed during reassembly — reusing old ones is a common cause of leaks and failure.
- After reassembly, the engine must be timed correctly and all bolts torqued to the exact specification in your manual before the engine will run.
Draining Coolant and Removing the Cylinder Head
Start with the engine cold. Open the radiator drain plug at the bottom of the radiator and let the coolant drain into a pan. Once empty, remove the radiator hoses and any heater hoses connected to the cylinder head. Disconnect the fuel lines (use a fuel line disconnect tool if your vehicle has quick-connect fittings) and the fuel injector connectors. Unbolt the intake and exhaust manifolds from the cylinder head.
Remove all electrical connectors from the cylinder head — spark plug wires or coil packs, temperature sensors, and any other wiring. Take a photo of the layout before you disconnect anything. Unbolt the valve cover and remove it along with its gasket. Now unbolt the cylinder head itself, working from the outside bolts toward the center in the sequence shown in your service manual. Use a gasket scraper to remove all old gasket material from the block surface.
Marking and Removing the Timing Chain or Belt
Before you touch the timing chain or belt, rotate the engine by hand using a wrench on the crankshaft bolt until the crankshaft and camshaft timing marks line up. Mark these positions with paint or a marker on both the crankshaft sprocket and the camshaft sprocket, and also mark their position on the timing cover. This is the most critical step — if you lose track of the timing marks, the engine will not run and you may bend valves during reassembly.
Unbolt the timing cover and remove it. If your vehicle has a timing belt, mark the direction of rotation with an arrow on the belt itself. Unbolt the camshaft sprocket and remove the timing chain or belt. Some engines have a timing chain tensioner that must be unbolted and removed as well. Keep all bolts organized in a labeled container so you know which bolt goes where during reassembly.
Removing the Old Camshaft
Unbolt the camshaft bearing caps in the sequence specified in your service manual — this is usually from the outside toward the center. Lift off each bearing cap and set it aside in order. Carefully slide the camshaft out of the cylinder head. Inspect the camshaft lobes for scoring, pitting, or wear. If the lobes are damaged, the new camshaft may fail prematurely if the valve lifters or rocker arms are also worn.
Clean the camshaft bore in the cylinder head with a clean rag. Check that the new camshaft matches the old one in length and lobe profile. Camshafts are not interchangeable between different engine variants, and installing the wrong one will cause poor performance or engine damage.
Installing the New Camshaft and Reassembling
Coat the new camshaft lobes and journals with clean engine oil. Slide it into the cylinder head, aligning the timing mark you made earlier. Install the bearing caps in reverse order, starting from the center and working outward. Torque each bolt to the specification in your manual — typically 10 to 20 foot-pounds for bearing cap bolts, but check your manual. Do not guess at torque values.
Reinstall the timing chain or belt, aligning the marks you made on the sprockets with the marks on the timing cover. Bolt the camshaft sprocket back on and torque it to specification. Reinstall the timing cover and torque all its bolts. Rotate the engine by hand two full revolutions and verify that the timing marks still line up. If they do not, stop and recheck your work before proceeding.
Reassembling the Cylinder Head and Engine
Install a new cylinder head gasket on the engine block. Carefully lower the cylinder head back onto the block and hand-tighten all bolts. Then torque them in the sequence specified in your manual, working from the center outward in stages — typically tightening to one-third torque, then two-thirds, then full torque. This prevents the head from warping.
Reinstall the intake and exhaust manifolds and torque them to specification. Reconnect all fuel lines and electrical connectors, using your photos as a reference. Install a new valve cover gasket and bolt the valve cover back on. Refill the radiator with fresh coolant and reconnect all hoses. Reconnect the battery.
Starting and Testing the Engine
Before you start the engine, turn the ignition key to the "on" position without starting it. This primes the fuel system. Wait a few seconds and listen for the fuel pump to run. Turn the key off, wait 10 seconds, and repeat this step two or three times. This fills the fuel lines and reduces the chance of air in the system.
Now start the engine. It may take longer than usual to fire because air is in the fuel lines. Once it starts, let it idle and listen for any unusual noises — a grinding sound or a loud ticking usually means the timing is wrong and the engine must be shut off when ready. If the engine runs smoothly, let it warm up to operating temperature and check for leaks around the gaskets and seals you replaced. Once the engine is warm, shut it off and let it cool, then recheck all bolt torques one more time.
Common Mistakes to Avoid
The most common error is losing track of the timing marks or reassembling the timing chain in the wrong position. This causes the engine to run poorly or not at all, and can bend valves if you try to start it. Always mark the timing before you remove anything, and verify the marks again before you start the engine.
Another frequent mistake is reusing old gaskets and seals. Gaskets compress and lose their seal over time, and reusing them almost always results in oil or coolant leaks within weeks. Budget for new gaskets, seals, and often a new timing chain or belt as part of the job. Skipping this step saves $50 to $150 in parts but costs you $1,000 in shop time to fix the leaks later.
Do not skip the torque wrench. Bolts tightened by feel are either too loose (causing leaks and noise) or too tight (stripping threads or cracking the head). A basic torque wrench costs $30 to $60 and is essential for this job.
Frequently Asked Questions
Do I have to replace the timing chain or belt when I replace the camshaft?
Not always, but it is strongly recommended. If the chain or belt is original and has high mileage, it is likely worn and may fail soon. Replacing it while the engine is already apart costs far less in labor than replacing it later. If the chain or belt is less than five years old and shows no visible wear, you can reuse it, but inspect it carefully first.
What if I cannot get the cylinder head bolts to come loose?
explore penetrating oil (such as PB Blaster or Liquid Wrench) to the bolts and let it soak for 30 minutes to an hour. Try again with a breaker bar rather than a regular wrench — the longer handle gives you more leverage. If a bolt still will not budge, stop and consult your service manual or a shop. Forcing a stuck bolt can break it, leaving a piece stuck in the block.
Can I replace just the camshaft without removing the cylinder head?
On some overhead-cam engines, yes — the camshaft is accessible from the top. On pushrod engines with the camshaft in the block, no — you must remove the engine or at least drop the oil pan. Check your service manual for your specific engine. If your manual shows the camshaft can be removed from the top, you can skip the cylinder head removal, which saves several hours of work.
How do I know if my camshaft is actually bad?
A worn or damaged camshaft usually causes a rough idle, loss of power, or a loud ticking noise from the valve train. A compression test can show if a valve is not sealing properly. If you have already removed the cylinder head for another reason, inspect the camshaft lobes under good light — they should be smooth and shiny, not pitted or scored. If they look fine, the camshaft may not be the problem.
What should I do with the old camshaft?
If it is damaged, it is scrap metal. If it is in good condition, some machine shops will buy it or trade it toward a remanufactured camshaft, which costs less than new. Check with local machine shops or salvage yards. Otherwise, dispose of it as scrap metal at a recycling center.