So I'm thinking I have a spun bearing on my 01 Ram. For the last several years it's had a knock when you start it up and it's cold out. This would go away as soon as it built oil pressure. It kind of seemed like a bearing, but it ran great with no other signs and it went away as soon as the oil pressure built up. It also only did it in the winter time. I've been driving it for years like that with no other issues. Well, it's started getting worse. Now it knocks even when it is warm out and it lasts longer than a few seconds. It will do it for 2-3 minutes and then it goes away and sounds fine. I'm thinking all signs point to a bearing, but I had a shop look at it and they said they weren't sure. I then had a friend that's a mechanic listen to it and he said it sounded like piston slap to him and that he'd keep driving it.

Well, the other week I let a friend borrow it and my trailer. When he brought it home I went out to back the trailer into the driveway and noticed the knocking was still there and the oil pressure seemed low. Right under 40PSI on the gauge. This made me think it had really spun a bearing now and that I should quit driving it. Well, it's sat for a few weeks without me messing with it. I decided to look at it today and I'm not sure it's actually any worse than it's been the last year or so. It still knocks on start up, but then it went away. The oil pressure does fluctuate. It's right under 40PSI at idle, but goes up significantly when on the gas. I can't remember if this is how it acted before or not. I kind of thought it stayed higher, but I may have only paid attention to it when it was cold. Does my oil pressure look normal?

Does this sound like a spun bearing to you guys? I'm debating if I should keep driving it, or if I should pull it down before it throws a rod through the block and costs even more money. I may change the oil and see if I see any metal in it.

I've attached a few pictures of the oil pressure at idle and while on the gas. You can also see a video of the oil pressure I'm seeing here:

Does that look normal for these trucks? I still obviously have a problem if it is, I'm just not sure if it's a bearing or what.

 

If I were you, I'd take some time to drop the oil pan and take a look to determine which rod (or rods) is giving you an issue. I suspect you have a severely worn rod bearing. Once you pull the oil pan and find the loose rod, pull the rod cap and see what the crankshaft journal surface looks surface looks like and go from there.

Post a photo or two with what you find.

 

All i really heard was the radio. Maybe try that again, just turn the tunes off....

 

I just wanted to show how to oil pressure fluctuated in this video and see if that was normal. It had already warmed up, so it wasn't making the noise at this time. I'll try to get a video when it is making noise.

 

Once I pull the oil pan, what do I want to look for to determine which rod it is?

 

Ah.

I expect oil pressure to fluctuate some. Higher when cold, lower at idle when warm, and increasing with RPM, to a point. Yours doesn't really look all that unusual. And of course, the oil pressure gauges in these trucks aren't the most accurate to begin with.

Not to mention, on yours, the oil pressure sensor sends the signal to the PCM, and the PCM tells the cluster what to display. (via a convoluted process.....)

Should be able to drop the pan without touching the motor mounts. Pull the braces, starter motor, (disconnect the battery....) and the dust shield, then, two million little bolts....... (slight exaggeration.... maybe...) and then you can wiggle the pan out.

You might be able to wiggle the bad rod with your fingers, but, if it was that loose, you would definitely hear it ALL the time...... may have to pull the caps, and see what the bearings/crank look like.

I would like to hear the actual noise before you go tearing into it though..... Might try starting the engine cold, with the serpentine belt removed, just to eliminate everything on the front of the motor.

 

I've pulled the oil pan off before, but it's been quite a few years. I remember it being a paint to maneuver back on, but doable. I'll try to get a video in the next few days of it making the noise to see if you can offer and guidance from that. I appreciate the responses so far.

 

Yeah, cold start, just the motor, no stero. (though, it DID sound good..... ) Lessee what ya got.

 

I think you have worn bearings not a spun bearing. I had a la with a spun bearing and it would get louder as soon as it got warmer. Tore the motor down ans seen one of the bearings overlapped the other. I had to get the crank ground also.

 

Thanks for the advice so far guys. I finally was able to take a video of the noise.

Does this sound like a worn bearing? It takes several minutes to go away.