Engine Noise?

[sweptliner]

I just started my truck today after not driving it for three days due to an infection. When it fired up I noticed that there was a click or knocking sound coming from the engine, I noticed that my oil pressure was a little low so I shut it down and checked the level. I found that I was at the ADD mark on the dip-stick, so i added about a quart, I checked it again and it was on the FULL mark. I started driving my truck around again and noticed the noise didn't stop, and when I am driving the needle on my oil gauge is in the middle or just a little above and when I come to a stop it dropps fast and thats when the noise starts to pick up again. This is the first time I have ever heard this sound and I have no idea where it is coming from. It isn't effecting anything with the performance, it still starts and runs smoothly and accelerates smoothly. I baby this engine so I don't know what is going on. It is an LA-318 with stock everything except for valve covers, and when the covers were off the springs and clearance looked good. Please help, Thank you.

[wideblock]

is it a light tapping from the top of the engine or a deeper knock from the guts? the light tapping is probably from a lifter that lost its prime while the truck was parked. it should go away with a little driving. the oil pressure drop at idle isnt uncommon on an older engine. id hook a real gauge to it so you can see what actuall pressure your running and go from there. you only need about 10psi per 1000rpm to keep everything ok. i had a truck that would do this when it was time for an oil change, on that truck, it told me when it wanted fresh oil...lol. also, what wieght oil are you useing?? i always run 20w/50 in mine, you might try bumping up at least one grade if its a higher mileage motor.

if its a deeper knock, id flush the engine and change the oil before driving it too much, you may have picked up some trash in an oil hole starving one of the rods or mains.

[712edf]

Yep

20W-50 in older or higher mileage motors raises the pressure. Use it in my 2004 astro-van with 130k.

bucky

[sweptliner]

I run straight 40W. I really can't tell weather or not it is a light knock or deep knock. Whats the difference in sound?

[wideblock]

lifter noise will sound more like if you tapped your screw driver on the fender lightly, and will have a faster rythm. the deep knock would sound more like a hammer on your frame.

[712edf]

lifter noise will sound more like if you tapped your screw driver on the fender lightly, and will have a faster rythm.

Now he'll need paint too!

Bucky

[sweptliner]

it sounds more like the screw driver on the fender.

[wideblock]

bet its a lifter that lost prime while it was parked. you might try flushing the engine and putting in fresh oil. drive it for at least 30 minutes to get her all nice and warm and see if it goes away or lessens. if not i would try popping off the valve covers and check the torque of the rocker bar. in the past, instead of an engine flush chemical i have had luck running it on trans fluid, at idle, for 15-20 minutes. heck, my old chevy ran a week with dextron in the pan, but i wouldnt reccomend that. the trans fluid is thinner and has a much higher detergent content then oil. gives the insides of the oil passages a real good scrubbing, sometimes better then the chemical cleaners. if cleaning doesnt get it, and the rocker bar is torqued proper, id go looking for a bent push rod. then again it could just be wear or a lifter going bad. to find a bent push rod, pull the rocker bar assembly, clean the push rods and lay them on a flat surface, roll them, the bent one will show its self pretty fast. also, check the ends for wear, compare them all, if one is more worn then the rest, it should be pretty obvious. check the rocker arms as well, where the push rods plug in, loss of oiling on a work engine can wear the rocker socket causing them to have too much slack and tap. if it gets to the point you have the push rods out, and you find a worn push rod or rocker, check the passage on the associated push rod, make sure its clean and flowing. if its all clear, theres a good chance the lifter has gotten trash in it and is blocking the oil passage. thats a much bigger problem.

[wally426ci]