For this procedure, special tools must be used, and it is advised that these tools are collected in advance. Because of the complexity of the work on timing chain replacement and proximity to the water pump, water pump should be inspected and replaced if necessary at this point. The 2.7L engine operates three timing chains: one for primary timing chain which controls valve timing in conjunction with crankshaft and pistons; two secondary chains that coordinate camshaft events such as intake and exhaust . Make sure step 19 is followed before removing the timing chain by looking at primary timing chain first. There are other steps involved in the removal process like disconnecting battery cable, relieve fuel system pressure, drain coolant system; remove cooling fan assembly, coolant reservoir, radiator, accessory drive belts, crankshaft pulley, upper intake manifold, valve covers , spark plugs, air conditioning compressor (without disconnecting lines). Furthermore steps include removing water outlet housing , idler pulley ,timing chain cover (be careful to identify bolt locations), aligning crankshaft sprocket's timing mark with oil pump housing mark ,and checking whether colored links on chain align with camshaft sprocket timing marks . Afterward primary tensioner for the primary should be taken out as well as its primary sprockets then Primary Timing Chain along with arm Guides' or even a Tensioner Arm must be also removed . Other parameters evaluated include condition of camshafts sprockets either on it or them as well as that of water pump plus crankshaft sprocket/s while examining wear/damage cases pertinent to timing chain/guides. Replace any component demonstrating excessive wear. During installation phase there are different things done including but not limited to installing crankshaft sprocket (if removed) checking proper primary timing chain alignment by aligning sprockets and colored links resetting and installing primary tensioner then securing camshafts sprockets. Complete the process with tightening of fasteners, application of sealant to timing chain cover gasket and sealing surfaces and refilling coolant system. For removal or installation of crankshaft sprocket, special tools such as a three jaw puller, propane torch or sprocket installer tool, and a machinist ruler or dial caliper may be necessary. With primary timing chain removed, crankshaft sprocket can be taken off using a three jaw puller whereas sprocket installer tool or propane torch may be used when installing by expanding sprocket hub for sliding it over the crankshaft. Caution should be practiced regarding handling heated components to avoid any injuries. Ensure that the installation depth on the crankshaft is accurately checked and measured.
