Skip the auto shop - Our mechanics make house calls

Q: A loud noise is coming from my engine

asked by on

it sounds like a bolt inside the engine, it is a very random noise not a constant timed sound, the transmission is a t56, and the flywheel was just replace with all new bolts. the pilot bearing was also just replaced, the engine just had a new cam, and new springs put in, i took the valve covers off and ran the engine and everything looks fine, i took the intake manifold off and the valves all look good from what i can tell. it sounds like a broken connecting rod, but the rods looked good when i took the oil pan off, and the engine has not been revved over 2500 since being in the car, just idled to move the car. so i don't see how the rod could have broke. i will have to pull the engine to check the bottom end so just wanted to see if anyone had any ideas. the noise is very loud and i don't want to run the motor and cause more damage. i also checked the starter and it seems like it is working properly not staying open and hitting the flex plate. i am at a lose at this poin

Hello - You don’t mention what make, model, or engine we are discussing, but with a T56 behind it, we’ll assume it is a V8 of significant size. There are many possibilities given the recent engine work, and your thoughts about connecting rod or main bearing problems are good guesses. Other possibilities, depending on the engine design, could include a loose oil windage tray, cam timing chain, tensioner, or variable-valve timing actuator, or a broken lifter or cam-follower, among other things. The possibility of a loose nut or bolt falling into the engine during the recent work is yet another nightmare to consider. I believe you are correct, the engine will need to be removed and torn down or at least have the pan removed to allow access so you can look for debris. If you would like some professional assistance with this, consider contacting a certified technician, such as one from YourMechanic, to take look and diagnose the noise. Good luck!

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. A loud noise is coming from my engine

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car is making metal on metal sound under hood towards passenger side

Hello. This noise can be coming from a few different places. If it occurs as soon as the vehicle is started then you may have a bad accessory pulley. It could be the AC compressor pulley or the alternator. It...

Q: My front drive wheel is making noise and when I break to stop the front of the car sways downward...there is a chirping/clicking noise

Hi there. I would really need to know what kind of car this is to be able to help you with this. From what you are explaining, it sounds like you either have a loose caliper or a brake pad...

Q: Hesitation when shifting gear and clanking noise and lack of power during acceleration

Hi there. It would appear there is a combination of problems happening with your vehicle. First, the transmission fluid and engine oil leak(s) need to be addressed. The fluid loss may account for the burning smell. The Check Engine Light...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.