weird knocking noise

[dylanrush]

2003 ranger edge 3.0L
126,000 miles


new: fuel pump, spark plugs, plug wires, cam synchronizer, brake master cylinder, catalytic converters

problem: my truck makes a weird knocking noise, i can hear it only inside the cab but not outside, seems to be coming from the right side of the motor. makes the most noise when starting or turning the motor off and it does it while it idles although it does idle smooth. if i touch the gas in the slightest bit, the knocking goes away and doesnt come back till it idles or i shut the engine off. it doesnt always make the sound when idling (probably 50% of the time) but it always does when starting or shutting the engine off. did a compression test and im getting about 125psi from each cylinder. possible worn motor mounts?


history: traded trucks and i got this truck with 124k miles. truck was said to pass smog and ran totally fine besides the fuel gauge not working. replaced the fuel pump and then the cam synchronizer after it started whistling. brakes went out around 125k and a new brake master cylinder fixed that problem right up. the truck didnt pass smog so i took the exhaust apart to find no cats what so ever. purchased 2 used cats and bolted them up, passed smog with flying colors. went ahead and ran a can of sea foam in the oil, gas tank, and vacuum line. the knocking sound is now coming around at 126k miles and i cant seem to figure out why or what it might be since i can hear it only inside the truck and not out. help?

 

[straycat]

It might be a timing issue or it might be a timing chain as well. Has it been replaced at the recommended service miles? 98-2005 3.0 engines have a timing chain.

 

[dylanrush]

what is the service limit on the cam chain? to my knowledge, it has not been replaced. i just tried to get video/audio of the problem but of course its not making the sound right now left the camera in the truck for whenever it starts making the sound

 

[PRanger]

what is the service limit on the cam chain? to my knowledge, it has not been replaced. i just tried to get video/audio of the problem but of course its not making the sound right now left the camera in the truck for whenever it starts making the sound

The timing chain in the 3.0 Vulcans are designed to last longer than your engine would ever. So there is no need to replace it. Did you change your oil since you ran seafoam through it? You shouldnt drive more than 150 miles or so with seafoam in your oil. To me if it's not consistent sounds like it could just be combustion from a bad batch of gas

 

[Rose2300]

Did you replace the spark plugs after you seafoamed it?

 

[dylanrush]

i havent changed the oil yet and i havent changed the plugs but i have sanded them and cleaned them up. the oil doesnt have much time on it past 150 miles so ill go ahead and change it tomorrow morning. ill cut apart the oil filter and see if i can find anything alarming. it did however, make the noise BEFORE i foamed it. i was wondering about the cam chain, seemed like the most unlikely culprit that i could ever think of. any other suggestions?