Our latest featured service is engine noise repairs on a 2002 Infiniti I35, brought to us by a client from Little Mountain, Vancouver.
The Infiniti I35 uses the Nissan VQ35DE V6 engine found in many models of Nissan and Infiniti cars and light trucks. This is a great engine: smooth, powerful and best of all, very reliable. In spite of these attributes this vehicle came to us in a very unhappy state with several noises were emanating from the engine area. They were so loud that, as the vehicle owner put it, the radio would not drowned out the sounds.
We performed an engine compartment noise diagnosis which consisted of two lengthy road tests with the vehicle warm and cold along with underhood and undercar inspections. Several interesting things were found: the timing chain had a horrible rattling sound and this was most noticeable when the engine was started cold. A loud rattle was present from the exhaust system and the engine had a horrible knock and pinging noise under certain throttle loads. Further inspection found the engine oil level very low, and the oil was old and dirty. Interestingly enough, the check engine light was on and we scanned the vehicle computer for codes where we recorded a P0021 stored code. This indicates an overadvanced cam timing from position A sensor.
From this information we determined that the low and dirty oil was likely causing both the timing chain rattles and the P0021 code because both of these components require clean engine oil and a full capacity to operate properly. After a hot oil flush and an oil and filter service the timing chain noise completely disappeared. This was great news for our client and it brings me to the moral of our story: do not let your engine oil run low and do not let it get dirty. Check it regularly and change it regularly. Modern engines are just too complex and expensive to damage by such simple neglect.
The other two noises were simply repaired by an overnight combustion chamber cleaning and repairing a loose exhaust shield. With all three of these repairs the vehicle sounded quiet and the radio was no longer required to mask horrible engine noises.
For more about the Infiniti I35 click here http://en.wikipedia.org/wiki/Nissan_Cefiro#Infiniti_I30
For more about the Nissan VG35DE V6 engine click here http://en.wikipedia.org/wiki/Nissan_VQ_engine#VQ35DE