This is gross :2:Dennis Fink said:It is the time of year when small rodents begin looking for a place to stay for the winter. A warm engine compartment is very attractive to them. Check under the hood for signs of rodent fatality. You know - blood, guts and fur.
Depending on the size of the varment, you'll get thumping noises and/or the sensation of a missing cylinder. A larger animal, like a cat, will generally give out a yelp.
Some of the organic parts may stick to the belt or fan blades. They can fling about and strike parts of the motor, accessory components or fan shroud causing a clattering noise.
Eric L. said:This might be really obvious, but did you first check the oil level on the dipstick?
I used to have some startup valve clatter on my Maxima too, but it was mainly cured when I switched to synthetic oil (which flows better on cold starts). You might want to demonstrate this to your dealership to see what they think, since you are still under warranty. Notice I said "YOU demonstrate" - I know how it feels when those Einsteins at the dealership cannot duplicate a problem (usually because they don't try hard enough). If they claim its normal, you are out of luck with that avenue, and I suggest trying Mobil One 5w30 to see if that fixes it.
My guess is that the oil was to one side of the oil pan away from the oil pump when it was parked in your driveway. The oil pump was not able to suck the oil up into the engine cylinders because of the steep slope in your driveway and the momentum of you moving forward. Thus the pump ran dry.Another thing, the day prior I was cleaning out my garage and left my MO parked in the driveway (steep decline) for a few hours. I parked my MO back in the garage and also had a strong gasoline order after I turned off the engine. Did not think twice about it until the next day and the engine started making this loud clacking noise