Loud knock gets louder when the engine is revved

Tiny
KLATHAM365
  • MEMBER
  • 2000 MITSUBISHI ECLIPSE
  • 3.0L
  • V6
  • FWD
  • MANUAL
  • 164,000 MILES
Every time I start my engine I hear a loud knock and then it stays at a constant sound and speed and every time I rev or give it gas it speeds up and gets louder. I have had numerous people tell me it could be bad lifters to a bent valve.
Do you
have the same problem?
Yes
No
Monday, October 17th, 2016 AT 3:47 PM

12 Replies

Tiny
CARADIODOC
  • EXPERT
Bent valves do not make noise. Lifters do not make a loud noise. Your engine does not even use lifters.

The noise "stays at a constant sound and speed", and "it speeds up and gets louder". Without any other clues or the ability to listen to it myself, a good suspect might be a loose harmonic balancer, (aka, vibration damper). That is at the "front" of the engine and has the pulley on it that drives the belt. With the engine running, watch that assembly to see if it is wobbling.
Was this
answer
helpful?
Yes
No
-1
Monday, October 17th, 2016 AT 4:37 PM
Tiny
KLATHAM365
  • MEMBER
If I could possibly post a video could that help?
Was this
answer
helpful?
Yes
No
Tuesday, October 18th, 2016 AT 3:53 AM
Tiny
CARADIODOC
  • EXPERT
Probably not. To post a video of the harmonic balancer you have to see it, so just watch it to observe if it's wobbling.
Was this
answer
helpful?
Yes
No
Tuesday, October 18th, 2016 AT 9:27 PM
Tiny
KLATHAM365
  • MEMBER
There is a loud tick coming from the front valve cover closest to the radiator and speeds up every time I press the gas
Was this
answer
helpful?
Yes
No
Wednesday, October 19th, 2016 AT 1:40 PM
Tiny
KEN
  • ADMIN
It sounds like a rod knock to me. It would help if you can post a video of the problem on youtube and then give us the link, then we can have a better idea.

Best, Ken
Was this
answer
helpful?
Yes
No
Wednesday, October 19th, 2016 AT 6:58 PM
Tiny
KLATHAM365
  • MEMBER
Is a rod knock an expensive fix?
Was this
answer
helpful?
Yes
No
Thursday, October 20th, 2016 AT 1:41 PM
Tiny
KEN
  • ADMIN
Yes, the engine basically need to be rebuilt or a new or used engine installed, sorry.
Was this
answer
helpful?
Yes
No
Thursday, October 20th, 2016 AT 9:30 PM
Tiny
KLATHAM365
  • MEMBER
https://youtu.be/Z0PcakMhgqY Here's the video
Was this
answer
helpful?
Yes
No
Friday, October 21st, 2016 AT 2:35 PM
Tiny
KEN
  • ADMIN
I have good news, its not a rod knock it sounds like you either have a broken valve spring or a a cam that has gone flat, start on the side that the noise is coming from and remove the valve cover, then grasp each rocker and try to move it to check for looseness. Some will be tight because they or in the cam lobe cycle. Turn the engine over by hand 90 degrees and check the others, then turn it 90 degrees again and check the rest.

Love the video BTW. Really helps, if you can rev the engine it see if the noise goes away which is another sign of valve train issues.

Best, Ken
Was this
answer
helpful?
Yes
No
+1
Friday, October 21st, 2016 AT 4:23 PM
Tiny
KLATHAM365
  • MEMBER
It doesn't go away just speeds up
Was this
answer
helpful?
Yes
No
Friday, October 21st, 2016 AT 4:59 PM
Tiny
KLATHAM365
  • MEMBER
And how much would that cost to fix?
Was this
answer
helpful?
Yes
No
Friday, October 21st, 2016 AT 4:59 PM
Tiny
KEN
  • ADMIN
Need to see what it is first, could be expensive if the cam is flat but only like $300.00 (US) if a valve spring is broken
Was this
answer
helpful?
Yes
No
Friday, October 21st, 2016 AT 5:20 PM

Please login or register to post a reply.

Recommended Guides