What does rod knock sound on Jeep Wrangler mean?
The sound could easily be mistaken for a valvetrain noise but goes away as the engine warms. A rod bearing or valvetrain noise will not go away. Hydraulic lifters bleeding down will likely continue after the engine warms up.
Why does my Jeep Wrangler 4.0L make a noise?
My 1999 XJ Cherokee’s 4.0L engine has had a subtle noise since we bought the Jeep at 94K miles. It sounds exactly as you describe. The sound could easily be mistaken for a valvetrain noise but goes away as the engine warms. A rod bearing or valvetrain noise will not go away.
Why does my Jeep Wrangler make a piston slap sound?
The sound could easily be mistaken for a valvetrain noise but goes away as the engine warms. A rod bearing or valvetrain noise will not go away. Hydraulic lifters bleeding down will likely continue after the engine warms up. A lean fuel mixture during warm-up phase can sometimes mimic a piston slap or pinging.
When does the lifter noise go away on a Jeep Wrangler?
However, the noise disappears when the engine warms, more like a piston symptom than a lifter (s). Lifter noise does not go away unless there is a lifter bleed-down or lifter bore problem that goes away with parts expansion. Parts expansion is less likely with an iron engine block.
The sound could easily be mistaken for a valvetrain noise but goes away as the engine warms. A rod bearing or valvetrain noise will not go away. Hydraulic lifters bleeding down will likely continue after the engine warms up.
My 1999 XJ Cherokee’s 4.0L engine has had a subtle noise since we bought the Jeep at 94K miles. It sounds exactly as you describe. The sound could easily be mistaken for a valvetrain noise but goes away as the engine warms. A rod bearing or valvetrain noise will not go away.
How long does piston knock last on Jeep Wrangler?
Even after that, there is some knock while engine is cold, that lasts about 2 minutes when engine is cold. After warm up knock is gone. In three years things were not getting worse, even knock is still there.
How big is a 6 cylinder Jeep engine?
Cylinder compression pressure. 120 to 150 psi. Oil pressure. At idle (600 rpm) 13 psi. Above (1600) rpm 37 to 75 psi. Bore diameter. 3.875 to 3.877 inches. Taper and out of round (Maximum) 0.001 inches.
Why does my Jeep Cherokee have a knock?
A few days ago the Jeep developed a very concerning knock, it almost sounded like a conrod bearing has gone, but it disappeared after a few minutes and was only there when the engine was completely cold.
Cylinder compression pressure. 120 to 150 psi. Oil pressure. At idle (600 rpm) 13 psi. Above (1600) rpm 37 to 75 psi. Bore diameter. 3.875 to 3.877 inches. Taper and out of round (Maximum) 0.001 inches.