I'm completely stumped... I have tried for over a year to figure out what is causing a knock / tick in my 5.9 magnum motor in my 99 Ram 2500.


>The motor runs as smooth as silk at idle. There is no noise at all.
>When you rev the motor it has a rattle/tick that starts about 2000 rpm. It doesn't matter if it's in neutral or being driven.
>As you drive, the sound only comes at a certain rpm range. If I let off it stops or if I add throttle it will go away. It does seem to get slightly worse as the motor warms up.
>I initially thought it was the torque converter bolts hitting or a cracked flex plate... It is neither.
>It sounds like it is coming from he right side.
>I have removed the valve covers and ran the motor with the covers off. All pushrods are tight and no rocker or lifter noises were found.
>The noise is not coming from the tensioner or alternator
>I have used a stethoscope and for the life of me can't figure out where the noise is coming from.
>There's no oil consumption and compression is good.
>The noise doesn't sound like a rod knock. It sounds more like a valve train issue but it's not detonation or spark knock.
>I cut open the oil filter. There's no metal.
>The motor has about 85K on it. The truck runs great. It just makes the ticking noise.
>I have checked for exhaust leaks at the manifolds...No leaks.
>There's nothing loose that's rattling. I have checked everything. I am frustrated to the point I am ready to pull the motor and rebuild it.

Preload OK? possible piston/pin issue (way less likely I'd think) but a person would not want to tear it down just to check that out. EDIT after rereading with it coming and going on/off throttle I think that elims preload. makes me think more rod/piston/pin possibility

Have you tried to run it without the belt on it?

This. The 5.2 in my truck was making an awful knock/screech/grind. I was sure it was the manual transmission. It was the water pump.

What does the dipstick look like? I had a replacement pan on a truck where the stick didn't go through the guide and would hut the crank.

Converter bolts hitting the inspection cover?

Just thought about it but...cat cons are know to break up and rattle on these trucks. Thump it and listen...

I will check the dipstick and water pump ideas. I know it's not the converter bolts. Already checked all that.

Unfortunately I had to go out of town for work I will be here until Friday. I won't get to check it until Friday.

My 79 Van does the same thing. Tried 4 different distributors, 3 TQ's no change. In the van, you can change timing while driving, can make it worse be advancing timing, but even major retard the sound never goes away. As you say, if you back off over 2200 rpm, it stops. Also noticed if the engine gets below ~8" vacuum, noise stops. #7 plug looks a little white, but can't find a vacuum leak. Taking a couple days off and I'm going to get after it. After about a year, it is no worse, and hasn't fixed itself yet, or blown up.

Wrist pin. You can figure out the cylinder sometimes by unplugging that wire and reving it to the point it does it and see if it went away. The piston is aluminum and expands more as it heats up than the steel pin does so the clearance and noise get greater as it warms up. They seem to get louder over a verrrrrry long time so it may seem no worse.

Well... I think I have discovered the problem... I pulled the belt and it still made the noise. I started pulling plug wires one by one and when I pulled the #3 wire the noise pretty much went away. It looks like HotRodDave is likely correct. I have to assume it's a wrist pin or rod bearing. The weird thing is the noise only occurs at certain rpms and goes away under load. I have no metal in my oil either. Pulled the plug and it looks great. I guess i am going to look for a rebuilt long block. I was looking at prices and I can get one for around $1,800. I don't think I could rebuild it myself for that, especially if the heads end up being cracked. I'm bummed...

Would it be possible for you to pull the pan in the vehicle & inspect the bearing/bearing journal/bolt/nut tightness

I can do that. If it's a bearing, isn't it best to go ahead and rebuild / replace? If it's one wrist pin, is it acceptable to pull the one piston and replace?

I'll defer to others for better opinions & agreed the prognosis ain't promising (esp for journal/bearing area) but I for sure would want to have a look see ahead of time. You might come out of this OK esp for a DD tho pulling a pan in the car ain't never fun. Do ya feel lucky? well do ya

I found a guy nearby that had a motor with 124K on it. I bought it for $400. I have a week of in a few weeks. I'm going to swap motors. I will change out all the gaskets and go ahead and put in a new oil pump and water pump while I have the motor out.

Timing cover and intake are the ones I comonly see leak, I wouldn't bother with the others they are pretty bullet proof. I see more replacement oil pumps go bad than the old factory ones, don't bother with it either. Throw in a double roller chain set and advance the cam 3*, that heavy truck will like a few extra pounds of TQ. Autozone and Oreilley can get them cheap with the adjustable slots, tell them it is a 68 340 dart or they will never find it. If you pull the heads you will see cracks and not feel comfortable running it so just leave em alone, if you do pull them put on the thin mr gasket head gaskets for a small compression bump.