Q: How to remove and reinstall a cylinder head on Four cylinder engine in a 2001 Toyota Avalon?
A: Before starting Toyota Avalon models, make sure the engine is totally cold. First, detach the negative battery wire, allow coolant to drain from the engine block and radiator, remove oil along with the oil filter. Step by step remove: throttle body, fuel injectors, fuel rail, intake manifold, and exhaust manifold. Then, take off three parts: timing belt, camshaft sprocket, and upper idler pulley. Take out the camshaft position sensor, then get rid of the camshafts, lifters, alternator, and distributor. Disconnect the power steering pump hoses, keep track of where things go, take off anything else that's left, and get ready for taking the head off. Use a quick, quarter-turn to loosen each bolt, then slowly lift off the cylinder head from the engine. Be extra careful if the head doesn't come off without force. Before cleaning or checking the head, take off all parts attached to the outside. To install the head correctly, wipe away dirt on the engine block's surface by scraping and cleaning thoroughly. Look for damage on both head and block surfaces; repair or fix threads in bolt openings. Rebuild worn bolt threads at the same time. Put back each piece we took off, put down the new gasket, and be really gentle when placing the new head on the block. Before installing each head bolt, spread clean engine oil on its threads. Then place each bolt back in its original slot and tighten, following the right order. Reassembling everything starts with the fuel delivery system, and as you put it back together, perform pressure checks on valves when needed. Then fill up the cooling system, replace the oil filter, top up with oil, and finish reinstallation. End with a road test, checking for leaks while you do the engine start and timing setup.