I have replaced my engine with a new one this past month because of the main bearing went on me. I now hear a knocking noise when the engine is cold and only in drive, once the engine warms up I no longer hear the noise. I also dont feel any vibrations or loss of power. Can it be something with the termostat?

 

I have 145k on my '02 and I am currently spending a couple of nights in the Tenn. mtns.It was 18 deg. here this morning, and I had a little more noise at start up. I'm running on a fresh oil change (5w20 Motorcraft) . There have been some posts about the relief valve in the oil pump being noisy,especially when cold. That's at least one possibility.

 

I just had the valve adjusted and new rocker arms installed and the noise is still there. It is heard on the passenger side and it is like a constant ticking noise when the engine is cold and then when it warms up it goes away but faintly. This only happens when I have it in the drive gear. I had it the mechanic three times and I dont think it is in the engine. I have new belts and the pulleys all seem to be OK. Any other ideas before I go back again. Thanks

 

meh129, you jinxed me man. This morning while starting my truck to go to church, I heard the knocking again. It was still there when I came home.It does get fainter when it's warm,but never goes away. It also comes from my passenger side. It sounds like my rocker arm(s) but it is hard to say for sure.It was really loud today. If it's not the rocker's , then it is probably a lifter. At least, that's what I'm afrain of.I'm off this week, I'll investigate more, and let you know.

 

I have a 2002 E250 with a 25k that makes a slight knocking when cold but it goes away when it warms up so I'm not too concerned with it. Mine sounds like piston slap.

 

sorry travlman, I return to my mechanic and the replaced two rockers and it seems now that it taps all the time. This is a new engine, and the main reason I brought the truck in the first place was because of the noise...I meet with the engine people next week so they can find the problem.. I'm stating to wonder if is a engine problem. Oh, I dont think it is the oil relief valve, because that was completly replaced with the engine. Let me know how it goes. Thanks meh

 

If mine is piston slap, it's seriously loud. This is actually more of a metallic tapping. It's very loud, and it's coming from the valve cover area,at least that's where it sounds like.It just started in the last 2 weeks, but is more prevalent when it's cold. Even when it's warm, it never goes away, you just have to lift the hood to hear it.

 

I dont hear my noise until I put it in drive and then accerlate, so it difficult to check on it from under the hood.

 

Mine is there immediately on start up when cold, and only gets quieter when warm. BTW, I have a five speed, so it's easy to put in neutral, but mine is unaffected by gear selection, and rises and falls with rpm. Tomorrow is supposed to be good weather, so I'll investigate farther, and keep you posted.

 

Thomas,
Always good to read your posts. Well, except for this!
Let us know what you find.

 

You bet, I wanted new rocker's, this may be an excuse. I can live with that, I just hope it's not a lifter.

 

Well, it don't look good.Meh, let me know what the engine people tell you. When I crawl under the truck, it seems louder. I had two experienced mechanics tell me it was a rod bearing. I had one mechanic tell me it was a wrist pin in the piston. I would rather it be the rod bearing, because I can replace those w/ the engine in the truck.If it's the piston or wrist pin, that's another story, especially if the cylinder is scored too bad. Wish me luck.

 

Thanks travlnman...sorry to hear about that...I will bring this up to the engine guys when I meet with them let and let you know what occurs. meh

 

I hope that's not your case, but you should have a warranty, you've already spent the money, now I may get to spend it. If you pull one plug wire at a time, if the noise is a bearing or piston , it should stop when you unplug the offending cylinder. I'm gonna try this tomorrow morning,bright and cold and early.

 

Well, the mystery deepens. Today, I pulled the right side valve cover to check the rocker's. They were fine. I buttoned it back up late this evening, and it was cold. I started it up, and there was only a small noise. I drove around the block, no noise. Upon my return, I was putting away my tools,the truck is sitting there idling smoothly. Suddenly, the noise comes back, while at idle, while warm. This makes me think, it may be a lifter, going in and out of normal operation. What makes the lifter's work, that's right, oil pressure. Could my oil pump be cavitating, and causing one or more lifter's to fail. My pressure gauge never moves, but I know that our trucks don't have a real pressure gauge, but an idiot light in disguise. Maybe the lifter is just going bad, I'm confused, and am open to suggestions.