Mercury 7T4Z-6K254-AA Tensioner - Timing Belt

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Relieve the fuel system pressure, then disconnect the negative battery cable. Loosen the water pump pulley bolts, remove the drivebelt and drivebelt idler pulley, and then remove the water pump pulley. Remove the fuel injection high pressure pump and housing. Remove the crankshaft pulley, ensuring the engine remains at TDC with the valve cover removed. Disconnect the Crankshaft Position (CKP) sensor electrical connector and remove the sensor, noting that a new sensor must be installed each time it is removed, along with a special alignment tool. Remove the power steering hose bracket fastener and bracket from the bottom of the cover. Support the engine from above with an engine support fixture and raise it enough to remove the right engine mount. Unbolt and set aside the power steering pump without disconnecting the hoses, then remove the pump bracket bolts and bracket. Remove the crankshaft front oil seal and the timing cover. Installation is the reverse of removal, ensuring to clean the mating surfaces of all sealant, install the engine cover within ten minutes of applying a 2.5 mm bead of RTV sealant, tighten the bolts in sequence to the torque specifications, install a new crankshaft front oil seal, verify proper crankshaft/camshaft timing, and install a new CKP sensor with the necessary alignment tool, not tightening the sensor mounting bolts until the installation tool is in place. For the timing chain and tensioner, remove the timing cover, compress the timing chain tensioner, and place a pin into the hole to hold it in the compressed position, being cautious to compress only the round plunger and not the ratchet mechanism. Remove the two tensioner mounting bolts and then the tensioner, followed by the loose timing chain guide and timing chain. The left chain guide and camshaft sprockets can be removed if necessary. Remove the camshaft alignment tool if installed, loosen both camshaft phaser and sprocket bolts without removing them, and use a wrench on the hexagonal area of the camshaft to hold it while turning the camshaft sprocket. Install the left chain guide if removed, then the timing chain, followed by the right chain guide. Install the timing chain tensioner and tighten the fasteners to the torque specifications, removing the pin to release the tensioner to engage the chain guide. Install the camshaft alignment tool, hold the camshafts in place with a wrench on the hex surface, and tighten the camshaft sprocket bolts to the torque specifications. Finally, install the timing cover, install the fuel injection pump housing ensuring the camshaft lobe is at its lowest point, and complete the remainder of the installation in reverse order.

To take out the timing cover, then turn off the engine and release the fuel rail pressure and unbuckle the negative terminal of the battery. Remove the water pump pulley bolts, next to the drivebelt and idler pulley you should remove the water pump pulley. After that, stand off the fuel injection high pressure pump and housing in addition to the crankshaft pulley and remove the valve cover so that the engine will stay at TDC. Pull the Crankshaft Position sensor electrical connector and then unbolt the sensor and finally position it with the help of special tool no. 303-1521. On any car of the 2014 model and previous years, unscrew the fastener and remove the bracket of the power steering hose from the bottom of the cover and then with the assistance of any attached stand raise up the engine to a level which will permit you to remove the right engine mount. For 2015 through 2018 models, loosen the turbocharger vacuum control valve bracket nut and harness retainer and push the assembly aside. On 2014 and earlier models, free the power steering pump and take it to the side without detaching the hoses, then, remove the power steering pump bracket bolts and the bracket itself. Take out the crankshaft front oil seal, all the bolts, stud bolts and the timing cover. Removal is performed with similar procedures but in reverse order, cleaning the mating surfaces of all sealant, attaching the crankshaft position sensor with alignment tool no. 303-1521 but not tightening the sensor mounting bolt until the tool is in place, installing new front crankshaft oil seal, tightening the bolts in sequence to torque specification in a definite time period after applying 2.5 mm bead of RTV sealant to the engine cover. To remove the timing chain and the tensioner, the timing cover should be pulled off, the timing chain tensioner compressed so that it can be held with a pin which will ensure that only the round plunger is compressed and not the ratchet mechanism. There are instances that it requires resetting if it is jammed, to reset the ratchet, you temporarily and gently place the tensioner in a vise, release the tension on the ratchet mechanism and then you put back the tensioner. The next step is to take off the two tensioner mounting bolts and this also gives ways to the tensioner and finally the loose timing chain guide and the timing chain. The left chain guide and camshaft sprockets can be unbolted in case of need, and if the camshaft alignment tool was applied before, it is to be withdrawn at this stage. Lose both the camshaft phaser and sprocket bolts but do not remove them. Tighten the nut of hexagonal area of the camshaft using a wrench and simultaneously turning the camshaft sprocket bolt. To install, do not rotate the camshafts during the process, then reinstall the LH chain guide if it was removed, and then the timing chain, and the RH chain guide. Place the timing chain tensioner, and tighten the bolt on the tensioner to lock it in position and then remove the pin that provides pressure to the tensioner. After engaging these areas, insert the camshaft alignment tool and while using a wrench to hold the camshafts, tighten the camshaft sprocket bolts. Lastly, there is the timing cover, the fuel injection pump housing and this must have the camshaft bearing lobe in the lowest position, and other parts installed vice-versa.

Disconnect the negative battery cable.

Remove the tensioner and place it lightly in a vise, with the jaws contacting the plunger and tensioner housing. Place a pick-type tool in the hole closest to the ratchet to relieve the tension on the ratchet mechanism. While holding the pick tool in place, move the ratchet back into the tensioner, then install a pin into the other hole to keep the plunger and ratchet compressed. Remove the tensioner from the vise.