FireInMe17

What should a normal healthy crankshaft sound like in a V6? I got under the car last night and noticed some noises, that have always been there, but now have me worried. The car runs great and has for the 32,000 miles that I've put on it. I've had no problems with it during everyday driving, and its good through all RPMs, its just got me concerned.

Rolling Thunder

In theory they should make no noise. They should ride on a thin film of oil so they never make metal to metal contact (kind of like ho an air hockey table works) and therefore no noise. However just because theres noise dosnt mean its from the bottom end. Keep in mind also the inside of the block is hollow so noise regardless of its origin tends to reverberate thought the whole block so it can be deceiving. Can you perhaps try to describe the sound better so we may help try and narrow it down?

FireInMe17

Its really hard to describe, I'll go take a video of the car running, top and bottom end to see what can be heard. You can hear the sound in the top end, but I always thought that it was just the intake and FI system and all that. But now that I can hear it on the bottom end, louder, its scaring me.

Rolling Thunder

Well I wouldnt be so concerned just yet. A few things you may want to try in the mean time is take a long screw driver and touch it to the bolts on the valve cover and the oil pan. If its a problem in the bottom end the sound heard through the screw drive will be more pronounced when you touch it to the oil pan bolt. Another thing you could do is one at a time disconnect each spark plug. If you disconnect one and the sound changes dramatically you have a problem in the bottom end on that cylinder. Just be sure to use a really well insulated tool to pull the plug wires otherwise you will get shocked and it will hurt lol.

FireInMe17

Ok so I did what you said, but I didnt get under the car because I couldn't find anything long enough to touch to the oil pan with out jacking up the car (no jack or stands ) with my ear to the engine, I couldn't tell a difference in the sound with any of the spark plugs unplugged, and your right, it does hurt, I got shocked twice haha.

But what does that mean exactly? That nothings wrong in the block or the bottom end and the noises are purely coming from the intake/valves/lifters/cam or something?

The noise is constant and just doesn't happen every now and again like its just one cylinder or two, its the whole thing. So either none of the cylinders are having problems or all of them are, but that would be kinda obsurb to think that a good engine with only 88K miles on it would be shot already!

The noise has a completely different sound from the plenum to the valve covers, its a lot louder from the plenum, quieter from the valve covers and the block, and then it gets louder again when underneath the car from what I know from the weekend being under it. Its confusing!

I have noticed a bit that when I take off at a normal rate that for a split second the engine or something in the engine bay hums or makes this vibrating sound, but I think that could just be one of the heat shields making noise, and it makes sense because I did have a problem with the engine making noises and it ended up being the heat shield by the smog pump, but now its a different pitch and a completely different sound.

Also, when and only when the engine is at ~1750 rpm and I'm going 35 mph there is a hum pause hum pause hum noise coming from somewhere thats hard to say, but I think its actually coming from my rear end and it makes sense because in over drive at 55 at around 1750rpm, it doesn't make the noise.

As you can tell I just really get freaked out about random noises that show up! I want to know why my car is making these noises too...

Rolling Thunder

Well what it means is that its looking good that your issues not in your bottom end. Not certain that its not yet but its looking good. Though I am a little confused about this?

"The noise is constant and just doesn't happen every now and again like its just one cylinder or two, its the whole thing. So either none of the cylinders are having problems or all of them are, but that would be kinda obsurb to think that a good engine with only 88K miles on it would be shot already!"

Are you saying that the noise is constant when it happens but does not always happen? Also about the its either all cylinders are having a problem or none are is it like the motors making a clattering sound? Kind of like all cylinders are ticking or none of them?

FireInMe17

The noise is only on start up, and it only happens every now and again, like its not something that happens every time that I start it. It can happen when the engine is hot or cold, so that makes me believe that its not piston slap,(piston slap goes away when an engine is hot, unless its been slapping for a long time,which mine hasn't been) and the fact that I couldn't hear anything out of the ordinary in any of the cylinders, firing or not, disproves piston slap.

And yes, I figured that either all the cylinders are making the same noise or none of them are and the noise is coming from the lifters or rocker arms or something along those lines.

Also, I've been reading the the noise just happening on start up is from using bad oil/cheap oil filters. I've been going to Sears lately to get cheap conventional oil changes with some cheap white filter for $18 bucks for a while. And the last two times they put 10W30 in the engine, when it says right on the cap that it takes 5W30. Its something that I didn't think much about until I read that an oil too thick for your engine will do things like that an not leave it lubricated as it should(common sense).

So I'm going to go get an oil change soon somewhere else and get better oil and a good Purolater filter or something other than a Fram or those cheap white ones Sears uses. And actually get 5W30 and NOT 10W30!

I think I'm starting to figure this out.

I was worried about piston slap, but I read that it usually happens within 20,000 miles on an engine, and mine has nearly 90K at this point, and it started out of the blue, with no signs, and the only thing I can think of is wrong viscosity oil and cheap filters, causing the engine to not get the lubrication it needs until after it starts spinning again, and not have it right off the bat like it should.

What do you think? Every time I try to record a video of the car starting/running, I try to get it off my phone to my computer, but it always has no sound, even though it worked on my phone so I guess a video it out of the question...