New Engine Clatter that rises with revs
#1
Former Vendor
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Until recently my 2001 Carrera Cab has run perfectly with no signs of problems. The car has only 58,000 miles and according to the engine number almost certainly has the early more reliable twin-row IMS bearing. Also it is a tiptronic which reduces the risks. So I decided to live with the current bearing.
I inspected the oil filter a few hundred miles ago and it was perfectly clean. Oil was changed 1,000 miles ago and 700 miles before that when the filter was also clean. It is cold here and it currently has M1 0w-40. Previously it had M1 5W-50. The oil filters are OEM.
A few days ago it started at 15 degrees below freezing with a clatter. As I drove it the clatter remained, getting louder to the point where it was obvious something was failing. I then stopped the car and revved it once. The clatter got louder with the increased engine speed.
When the filter was inspected it looked clean. In the bottom of the filter canister was a small oil pool with fine metallic dust which could only just be seen by looking closely and because the dust shone a little in the light. The dust could be picked up with a magnet but was barely visible in the oil - very low density.
Ideas?
I inspected the oil filter a few hundred miles ago and it was perfectly clean. Oil was changed 1,000 miles ago and 700 miles before that when the filter was also clean. It is cold here and it currently has M1 0w-40. Previously it had M1 5W-50. The oil filters are OEM.
A few days ago it started at 15 degrees below freezing with a clatter. As I drove it the clatter remained, getting louder to the point where it was obvious something was failing. I then stopped the car and revved it once. The clatter got louder with the increased engine speed.
When the filter was inspected it looked clean. In the bottom of the filter canister was a small oil pool with fine metallic dust which could only just be seen by looking closely and because the dust shone a little in the light. The dust could be picked up with a magnet but was barely visible in the oil - very low density.
Ideas?
#5
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How long has it been since you last started it?
Also did you let the motor run up to operating temps or were you too afraid and just shut it down after you revved it once?
It could be the colder temps are preventing the oil from fully lubing the lifters in a timely manner.
If you haven' t run the car up to operating temps, there could be a chance that oil will never fully lube the lifters to quiet them down again.
It happened to me once before where it took 10 min for the lifter noise to go away. Never had it happen since.
Also did you let the motor run up to operating temps or were you too afraid and just shut it down after you revved it once?
It could be the colder temps are preventing the oil from fully lubing the lifters in a timely manner.
If you haven' t run the car up to operating temps, there could be a chance that oil will never fully lube the lifters to quiet them down again.
It happened to me once before where it took 10 min for the lifter noise to go away. Never had it happen since.
#6
Range Master
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Water pump.
#7
Race Director
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Well, you said it was obvious something was failing. What it is I have no idea, just guesses. But my guesses don't matter.
My advice would be to flat bed the car to a good Porsche shop and get a pro tech's diagnosis.
Any more running of the engine should only be done under the supervision of the tech as he diagnoses the source of the noise.
Try to avoid fretting too much. The noise would just be a bad water pump or something out side of the engine. But let the tech make the diagnosis.
My advice would be to flat bed the car to a good Porsche shop and get a pro tech's diagnosis.
Any more running of the engine should only be done under the supervision of the tech as he diagnoses the source of the noise.
Try to avoid fretting too much. The noise would just be a bad water pump or something out side of the engine. But let the tech make the diagnosis.
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#8
Former Vendor
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I'm sorry I wasn't clear. I drove the car ten miles with the clatter then stopped, revved it and shut it off. I had assumed the clatter was the cold but closed it down when it was obvious it was not the case. I flatbedded to my mechanic and opened up the filter in his shop. We're next going to empty the oil for examination and probably dropping the pan hoping to see the reason.
#12
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Pelican Parts has an article on the design transition. Turns out it was not a clean cutover and you don't know until you see it. But they provide an engine number where lower numbers likely have the old bearing.
#13
Burning Brakes
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This may sound out of left field but it happened to me. I had pulled over and heard a loud rattle coming from the bottom end of my car. The death rattle. It increased w/revs but all vital signs were good (oil pressure, vacuum, oil color, coolant color). I had the car flatbedded to my tech expecting the worse.
I got a call from my tech a few hours later hoping for the best but expecting the worst. It was...
...a bad catalytic converter. Whew. It was very hard to discern where the noise was coming from being the cat is right in front of the oil pan. Even my tech who is a seasoned 996 specialist had to drill a hole in the cat and stick a rod inside to put pressure on the element (the rattle then stopped) to confirm it was indeed the cat and not a lower end rod bearing or similar.
Here's to hoping it's a simple, cheap remedy....
I got a call from my tech a few hours later hoping for the best but expecting the worst. It was...
...a bad catalytic converter. Whew. It was very hard to discern where the noise was coming from being the cat is right in front of the oil pan. Even my tech who is a seasoned 996 specialist had to drill a hole in the cat and stick a rod inside to put pressure on the element (the rattle then stopped) to confirm it was indeed the cat and not a lower end rod bearing or similar.
Here's to hoping it's a simple, cheap remedy....
#14
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Just curious what your rationale was to drive it for 10 miles with the clatter? I'm hoping you didn't damage the engine more by driving it. Also just doing a visual on the oil isn't good enough. I would send a sample to Blackstone or other analysis place.