Need help diagnosing a tap (Vid inside)
Joined: Jun 2008
Posts: 2,142
Likes: 29
From: Bethlehem, PA
Need help diagnosing a tap (Vid inside)
Hey guys, I have a 2006 6MT G35 with the VQ35DE Rev-up, 66k on it.
Problem: 2 noises, both start at the exact same time. Tapping/knocking noise from the cylinder, driver's side, closest to the TC cover. Most audible when the stethoscope is on the coil pack. Possible lifter, but sounds heavier. Noise 2: Some type of chain slap from the secondary camshaft timing chain, possibly against the cover. Most audible on the VTC cover, the circle closest to the fender. Both kick in at the exact same time. They are only present when the car is warm, consistent in volume and follow the RPM's, lost to road noise when driving. Moderate volume. No apparent loss of power.
Additional Info: These problems will only start after the car is warm. When the car has been "cold-soaked" overnight, the engine sounds perfect for about 3-5 minutes of idle. Maybe a very light lifter tick. Then boom, both problems arise simultaneously and only take a couple of seconds to kick in. Secondary timing chain appears to hold tension when cold, then lose it upon warm-up. I seafoamed through the vacuum booster, which made the problem louder.
When/How did it start?: About 2 months, ~1000 miles ago. Drove the car hard before a proper warm up during a cold night, no problems, short 3 min drive. Running low on oil, probably around 4-4.2 qts in the eninge. Stupid, I know, I will never do it again. The next morning, while idling waiting in a drive-thru, I heard a loud bang. I thought I got hit or jerked the clutch, but it might have come from the engine. It's still possible it was the clutch, but I don't think I was moving at the time and I don't mess up the clutch very often. I thought I got hit it was so loud.
My Guess: Tensioner? VTC pulley or Cam Sprocket? Just a out of spec lifter? I think if it was the lifter it would be just as loud when it was cold. I remember reading that one of the pulleys has a spring that holds tension until oil pressure takes over, and I'm guessing a small leak causes the spring to disengage but not hold tension. I'm kinda just guessing though. Please let me know if you guys need more info.
So, what do you guys think? I really can't afford to have Infiniti dick around and charge me a ridiculous amount to diagnose it. I'm willing to paypal someone $20 if they can correctly diagnose the problem, since I really want to DIY and not take it to a shop since I'm a college student and low on cash. I really want to make sure I buy the right part(s) instead of dropping 500 on a VTC pulley and have it not fix the problem. Right now I'm feeling :suicide:
Problem: 2 noises, both start at the exact same time. Tapping/knocking noise from the cylinder, driver's side, closest to the TC cover. Most audible when the stethoscope is on the coil pack. Possible lifter, but sounds heavier. Noise 2: Some type of chain slap from the secondary camshaft timing chain, possibly against the cover. Most audible on the VTC cover, the circle closest to the fender. Both kick in at the exact same time. They are only present when the car is warm, consistent in volume and follow the RPM's, lost to road noise when driving. Moderate volume. No apparent loss of power.
Additional Info: These problems will only start after the car is warm. When the car has been "cold-soaked" overnight, the engine sounds perfect for about 3-5 minutes of idle. Maybe a very light lifter tick. Then boom, both problems arise simultaneously and only take a couple of seconds to kick in. Secondary timing chain appears to hold tension when cold, then lose it upon warm-up. I seafoamed through the vacuum booster, which made the problem louder.
When/How did it start?: About 2 months, ~1000 miles ago. Drove the car hard before a proper warm up during a cold night, no problems, short 3 min drive. Running low on oil, probably around 4-4.2 qts in the eninge. Stupid, I know, I will never do it again. The next morning, while idling waiting in a drive-thru, I heard a loud bang. I thought I got hit or jerked the clutch, but it might have come from the engine. It's still possible it was the clutch, but I don't think I was moving at the time and I don't mess up the clutch very often. I thought I got hit it was so loud.
My Guess: Tensioner? VTC pulley or Cam Sprocket? Just a out of spec lifter? I think if it was the lifter it would be just as loud when it was cold. I remember reading that one of the pulleys has a spring that holds tension until oil pressure takes over, and I'm guessing a small leak causes the spring to disengage but not hold tension. I'm kinda just guessing though. Please let me know if you guys need more info.
So, what do you guys think? I really can't afford to have Infiniti dick around and charge me a ridiculous amount to diagnose it. I'm willing to paypal someone $20 if they can correctly diagnose the problem, since I really want to DIY and not take it to a shop since I'm a college student and low on cash. I really want to make sure I buy the right part(s) instead of dropping 500 on a VTC pulley and have it not fix the problem. Right now I'm feeling :suicide:
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