today the temperature suddenly dropped by a lot and my engine noises started to get louder
the noise sounds like a rod knock, but i don't think it is. i don't know if oil has anything to do with it, but it's my first time since last summer i putted 10w-30 oil in the car (used 5w-30 during winter)
here's the description:
in the morning i started the car, it turned right over.the knock isn't very noticeable, somewhat of a quiet knock in the back ground. i revved the engine...the engine sound would completely cover the knock, but when i put a screw driver to one of the intake tube, i can still hear the sound. it does seems like that the frequency of the knock increases with the speed. i'm pretty positive that it is coming from the engine, but i couldn't locate which cylinder it's coming from. then when i shifted the gear into reverse (or drive) with the brake pressed the engine is put under load, and the noise become loud and clear. it's like "knock..knock..knock" not very fast knock but rhythmic. during driving, the noise only comes out when the engine is under load ie. accelerating (even the slightest push on the gas makes the noise come out, but the noise completely disappears when i let go of the gas pedal)
when the temperature is hot, the noise would hardly be there. today it dropped close to freezing, the noise stayed for a good while. i don't think it's piston slap, since the noise is still there even when the engine is at full temperature, but it will eventually quiet down after about 5 miles of driving.
the knock sounds almost like a spun bearing, but it only comes out when the engine is under load in cold weather. i recently replaced the exhaust gasket, but i didn't have the exhaust manifold machined. between cylinder 2 and 3 there is a gap between the manifold and the gasket. i could slide a piece of paper in. the gap is only in the area between cylinder 2 and 3 exhaust port. i don't think it's leaking exhaust because the piece of paper will not slide in between the exhaust port and the exhaust tube.
any ideas and suggestions on where i should look for would be much appreciated.
the noise sounds like a rod knock, but i don't think it is. i don't know if oil has anything to do with it, but it's my first time since last summer i putted 10w-30 oil in the car (used 5w-30 during winter)
here's the description:
in the morning i started the car, it turned right over.the knock isn't very noticeable, somewhat of a quiet knock in the back ground. i revved the engine...the engine sound would completely cover the knock, but when i put a screw driver to one of the intake tube, i can still hear the sound. it does seems like that the frequency of the knock increases with the speed. i'm pretty positive that it is coming from the engine, but i couldn't locate which cylinder it's coming from. then when i shifted the gear into reverse (or drive) with the brake pressed the engine is put under load, and the noise become loud and clear. it's like "knock..knock..knock" not very fast knock but rhythmic. during driving, the noise only comes out when the engine is under load ie. accelerating (even the slightest push on the gas makes the noise come out, but the noise completely disappears when i let go of the gas pedal)
when the temperature is hot, the noise would hardly be there. today it dropped close to freezing, the noise stayed for a good while. i don't think it's piston slap, since the noise is still there even when the engine is at full temperature, but it will eventually quiet down after about 5 miles of driving.
the knock sounds almost like a spun bearing, but it only comes out when the engine is under load in cold weather. i recently replaced the exhaust gasket, but i didn't have the exhaust manifold machined. between cylinder 2 and 3 there is a gap between the manifold and the gasket. i could slide a piece of paper in. the gap is only in the area between cylinder 2 and 3 exhaust port. i don't think it's leaking exhaust because the piece of paper will not slide in between the exhaust port and the exhaust tube.
any ideas and suggestions on where i should look for would be much appreciated.