Minggu, 26 Juni 2011

How to Check and Replace a Timing Chain in a Nissan Altima

Like timing belts, timing chains drive a vehicle's camshaft. Stronger than their counterparts, timing chains are nearly repair-free with no definitive replacement schedule. If your Nissan Altima produces a vociferous rattle whenever you accelerate, chances are it's time to check and replace your timing chain. Here's how that's done in Altimas with a 2.4L engine.
Difficulty: Moderately Challenging
Instructions
Things You'll Need
New timing chain
Basic automotive tools
Remove Your Timing Chain
1

Check your owner's manual for the recommended mileage for replacing your timing chain. Replacement for a Nissan Altima is 60,000 miles.
2

Locate the timing chain. Replace it if the automatic chain adjuster (also known as the tensioner) is damaged or worn.
3

Drain the cooling system and disengage the negative battery cable. Undo the spark plug wires and set the No. 1 piston at "Top Dead Center" (TDC) of the compression stroke.
4

Disconnect the engine undercover, vacuum and fuel hoses, harness and connectors, drive belts, power steering reservoir, alternator and bracket, upper radiator hose, air duct, front exhaust tube, intake manifold collector supports, collector and exhaust manifold and the distributor.
5

Prop up the oil pan and take out the front engine mounting, the valve cover, camshaft sprockets, cam bearing caps, camshafts, cylinder head bolts (reverse the installation order), cam sprocket cover, upper chain tensioner, chain guides and chain, idler sprocket bolt, cylinder head, intake manifold and cylinder head gasket and the steel oil pan.
6

Place a steel cutter between the steel and aluminum oil pans. Slip the cutter around the oil pan's edge. Disengage the steel oil pan, baffle plate, oil strainer and the front tube.
7

Secure the car on jack stands and place a seal cutter in between the oil pan and cylinder block. Slip the cutter around the oil pan's edge.
Install Your Timing Chain
1

Reconnect the crankshaft sprocket, oil pump drive spacer, idler sprocket and lower timing chain. Position the lower timing chain on the sprockets and line up the mating marks.
2

Rub on an unbroken bead of liquid gasket and put in a new front cover and oil seal. Secure the bolt at 105 to 112 foot pounds (142 to 152 Nm).
3

Eliminate any old material from the pan and cylinder block mounting surfaces. Rub on a 3.5 to 4.5mm bead of liquid gasket over the oil pan and cylinder block.
4

Attach the upper timing chain to the idler sprockets and secure the cylinder head bolts.
5

Refill the cooling system and add clean oil in the engine.
6

Hook up the negative battery cable and any other disconnected parts or items. Start the engine and look for leaks.

Tips & Warnings

Procedures for replacing timing chains in Nissan Altimas vary slightly depending on engine size.

Make sure the new timing chain matches the chain you are removing.

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