My truck has been making a knocking noise upon acceleration. Today the knocking is constant and louder. What could this be? Pistons? Oil sludge? New motor?

  • Can you add some information? Does the knocking stay in time with engine speed or road speed? Does volume of the knocking increase under certain conditions? How many miles are on the truck? Have you looked for metal shavings in the oil during an oil change? Thanks and Cheers! – DucatiKiller May 10 '16 at 21:24
  • Constant with engine. Louder when you accelerate. 197000 miles. Haven't noticed any shavings – ablank13 May 10 '16 at 21:40
  • See my answer here....mechanics.stackexchange.com/a/29550/16882 – Moab May 10 '16 at 23:56
  • Shavings will be seen in fast failures, more than likely yours is normal wear of the rod-crank bearings and crankshaft over time, this will show no noticeable shavings. The wear is slow and small particles will be drained with each oil change. – Moab May 11 '16 at 0:00

The 3.7 is notorious for having a rocker arm fall off and or lifters collapsing. This is usually accompanied by a check engine light being illuminated.

Use a stethoscope or a long screw driver and try to isolate where the knock is coming from.

If it's coming from a valve cover, remove the valve cover and you're likely to find a rocker laying around. If this is true you need to thoroughly inspect the valve train components.

  • Knock sounds like it's coming from the bottom of engine – ablank13 May 10 '16 at 21:47
  • 1
    @ablank13 Try removing the serpentine belt to rule out a bad water pump or accessories. But if it's truly coming from the bottom of the engine you're going to need to pull the pan and inspect everything. – Ben May 10 '16 at 22:09
  • The early Hemi V8 engines had catastrophic valve train failures also, Dodge quality. – Moab May 11 '16 at 0:01

Remove the valve cover and oil pan and inspect for rod bearing damage. Black or discolored rod caps are good indicators of spun bearings. Then, check the valve train for damage, failed lifters, heavy pitting, etc. If everything comes up good, then I suspect the timing guides or chains.


what about 2008 Dodge Magnam-v6 ride knock

  • Welcome to the site. If you'd like this answer taken seriously, you'd explain what "ride knock" is, and how it can be fixed or alleviated. Just saying it exists makes this a very weak answer. – Pᴀᴜʟsᴛᴇʀ2 Jul 7 '17 at 18:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.