Quote:
Originally Posted by 1991ZR1
My engine makes this noise too. I assumed that it was the tensioner. Or at least hoped that was the cause. I really hope it's not the timing chain. Maybe we have different causes of the noise.
I have a very rough running engine and that may or may not be related. I was thinking the rough running and the Goodyear belt being long contribute to the tensioner making a clacking sound.
When I increase the rpm a little, the noise goes away.
The noise also goes away if I turn off the air conditioner. I don't think the noise is the air conditioner though. I think taking the load off the engine helps it run a little smoother.
I can't hear the noise while driving. I can only hear the rough running engine.
|
A rough running....and rough idling engine noise would probably be dual mass flywheel noise. But you can definitely here where that is coming from. The rough running would probably be caused by poor injectors assuming you have good plugs, coils and not running on a dead cylinder.
Does your engine make more noise on one side or other?
Quote:
Originally Posted by cmb
Thanks everyone for your input. It sounds like my best course of action now is a combination of warmer weather, lower-viscosity oil, perhaps more Marvel, and longer runtime to really allow the oil to come up to temperature.
Sure enough, the oil temp gauge had just barely moved off its lower stop after 15+ minutes of idle in 30-35 degree ambient.
|
It is hard to believe that a lifter would not pump up after 15 minutes.....or even 15 seconds no matter what oil you used. I assume the oil pressure comes right up within 3 or 4 seconds after start and is probably near 75 lbs? An ambient temperatures of 30 deg is not all that cold. I have started engines (not LT5s) at zero with 10W-30 Penzoil. After 15 minutes of idle the engine should be near 180 deg F even in 30 deg ambient temperatures. The thermostat will just not open as far in cold ambient temperatures.
A collapsed lifter is one that has excessive (very excessive) leak down as all lifters will collapse (leak down) after sitting for hours or days.
In other words....excessive internal plunger wear would have caused the excessive leak down of the lifter and unusual for a low mileage engine. A lifter that has clogged oil ports would not pump up and essentially be a collapsed lifter.
The oil will remain cooler given the oil pan and bottom of the engine is not cooled by coolant but by air flow and outside air temperates (assuming the oil cooler flow is zero at those temperatures). Oil flow is about 1.5 gpm at idle so would take about 2 minutes for oil to completely circulate giving a 2 minute cooling off period once back in the cool oil pan.
On Wed Mar 4th the high will be 3 deg F and low will be -12 deg F. In those temperatures would have to turn on Good Ole Val6 diesel Infrared 112,000 BTU Heater
I would do a compression test because it is such an easy test and only takes a few minutes just in case there is something going on with the valves, pistons.
Keep us posted on what is determined to be the cause of this clatter on the LT5 engines. Good information for everybody
