Hi all

Hoping to get some help with noise on my 324. Not sure if the noise has always been there. Can’t tell if it’s a knock from the engine itself or if it’s something external, perhaps pulley/waterpump. Oil pressure is good (assuming gauge is correct) doesn’t smoke or seem to burn oil. No smoke from tailpipe or anything unusual. Running Valvoline vr1 10w30 oil with zinc. Also for what it’s worth, it’s seems to dissipate the
Hotter it gets, and it seems to come and go. Please check out all the videos and let me know what you think!

https://youtu.be/yMnn6vMQ2LY
https://youtu.be/yMnn6vMQ2LY

 

It isn't as apparent in #3 as it is in #1 & #2. You'll have to do some things to try to isolate it. Remove or slacken the drive belts and run the engine BRIEFLY. It could be one of the belt driven items. Try a stethoscope. Sometime it can pinpoint it.

 

yeah video #3 was taken after the car was driven for a bit and warmed up. The first one was taken when stone cold

 

Second the idea of removing belts to try to isolate noise, use a long screwdriver to an ear, should be able to tell source. Seems to have more valve train noise then my 324.

 

I noticed the fan belt was jumping a lot, something is out of square or round there in that area . The sound does sound ominous but not exactly like a rod or main. A little history would help. When did this start and what have you done as far as mechanicals in the past? If all inspections fail to show/ find a problem on the exterior as a TEST only you might allow engine to come to operating temp then add a pint of STP and see if it quickly reduces noise you will know it is a internal issue in the rotating assembly,If it doesn't start looking for a issue in the water pump area. It would help if you could get the engine to idle as slow as it will run and listen with a stethoscope as Ozzy suggested.... Just my thoughts ...Tedd

 

hey tedd
appreciate your reply! I don’t think the noise existed when I first got the car as I think I would’ve noticed but could’ve gone overlooked. The motor was supposedly rebuilt back 15 or so years ago and ive probably but more miles on it in the past year than it had in the previous 15. Last season it got rebuilt carb, drained and cleaned tank, new fuel pump, radiator boiled out, new plugs, pertronix ignition, power master alternator that mounts and looks like stock generator. My first inclination was that it was coming towards the front but now my paranoia is making me hear it all over so it’s hard to say. I used Valvoline vr1 10w30 zinc oil. It’s definitely due for a change but as far as I can tell the car runs well with no smoking or burning oil and if the oil pressure gauge is correct which I think it is, it sits right at 30 when idling In traffic, between 30-60 mark when it’s idling in park and pegs up high when I’m cruising at a higher speed. I changed one side of the valve cover gasket last summer and from what I ciuof
trll it looked properly lubricated up top
to the rockers.

 

To me it doesn't sound like a stuck lifter but if it needs a oil change now is the time to try that. I had a 394 that would religiously stick a lifter at 3000 miles since it's last oil change. That will bring you to attention in a hurry especially at night at 70.

The fact that it is holding great oil pressure at low RPM also makes me think it is not a rod or main bearing but that bouncing fan belt looks suspicious to me...... Tedd

 

tedd,
what would be the cause of a bouncing fan belt? Poor tension? Bad bearing somewhere? Pulley worn out?

 

If it is a faint knocking noise, a couple of my 59's were making a noise like that. Come to find out it was the fuel pump making that noise, nothing to worry about if it turns out to be that ran my car 27 years with it.

 

Don't know without being there and hearing to it myself sometimes the sound I get from the computer isn't accurate enough to tell subtle differences. To me it has a tiny ring to the knock and as you said the oil pressure is good throughout the idle to higher rpm range.. If mine I would pull that belt off and spin the fan and the water pump, power steering and see or feel for bad bearings. Could be something (rubber) going bad with the harmonic balancer if it is original. How is the timing, has it slipped any?

What does the oil look like, any metallic particles floating around ? You have something not good going on there I would not get to far from home until you find out what it is.../ Keep us in the loop.... Tedd

 

Did you ever discover the source of your knock? Mine just started the same thing.

 

I guess I missed this post last year. To me it sounds like two things. It sounds like it has a exhaust leak which can sound like a knock and it sounds like the rocker arms are clattering. The first generation of Olds engines are pretty well known for rocker arm noise.