Engine Knocking or Exhaust?
Thread Starter
Race Director
Joined: Dec 2000
Posts: 10,896
Likes: 2
From: CO
Engine Knocking or Exhaust?
I was driving my Vette in a snowstorm and the snow was hitting the bottom of the car. It was really slushy and really deep. Pry a foot at least.
While I was driving I started to hear a knocking sound. Actually it sounded like some snow hitting the fan. thump thump thump. I figured that it would clear up when the snow hitting the fan either melted or got kocked off. Well...the sound didn't stop. It actaully kept going. It was late so I parked the car and went inside.
I started it the next morning and the sound was still there. It was pretty loud actually. I looked for snow that might have been caught up and there was quite a bit around where the diverter valve connects to the exhaust pipe. I removed it and started the car, Same sound. My next thought was that it could be an exhaust leak of some sort.
I was wondering how I could tell? Would it be possible to disconnect the coil wire and turn the car over ? I figure that if it still makes the sound then it could be a rod or something inside the engine. If it doesn't make the noise then it must be exhaust? Does this sound right?
While I was driving I started to hear a knocking sound. Actually it sounded like some snow hitting the fan. thump thump thump. I figured that it would clear up when the snow hitting the fan either melted or got kocked off. Well...the sound didn't stop. It actaully kept going. It was late so I parked the car and went inside.
I started it the next morning and the sound was still there. It was pretty loud actually. I looked for snow that might have been caught up and there was quite a bit around where the diverter valve connects to the exhaust pipe. I removed it and started the car, Same sound. My next thought was that it could be an exhaust leak of some sort.
I was wondering how I could tell? Would it be possible to disconnect the coil wire and turn the car over ? I figure that if it still makes the sound then it could be a rod or something inside the engine. If it doesn't make the noise then it must be exhaust? Does this sound right?
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: Engine Knocking or Exhaust? (flood)
Is it a thump or a knock? If a knock, how is your oil pressure? Any holes in pipes/mufflers? Any chance you have loose accessories on the front of the engine (fan/belts/accessories secure?)?
I had a rocker break at the stud when the temperatures dropped one winter back in 1983.
I had a rocker break at the stud when the temperatures dropped one winter back in 1983.
Thread Starter
Race Director
Joined: Dec 2000
Posts: 10,896
Likes: 2
From: CO
Re: Engine Knocking or Exhaust? (TedH)
Is it a thump or a knock? If a knock, how is your oil pressure? Any holes in pipes/mufflers? Any chance you have loose accessories on the front of the engine (fan/belts/accessories secure?)?
I had a rocker break at the stud when the temperatures dropped one winter back in 1983.
I had a rocker break at the stud when the temperatures dropped one winter back in 1983.
Melting Slicks
Joined: Mar 2001
Posts: 3,365
Likes: 5
From: Lake Villa IL
Cruise-In IV Veteran
Cruise-In V Veteran
St. Jude Contributor
Re: Engine Knocking or Exhaust? (flood)
You can use a long screwdriver (carefully) as a stethoscope. Put the end of the screwdriver, the business end, on different parts of the motor. Put your ear (don't wear a neck tie or other loose clothing when doing this :eek: :D ) against the handle. You'll hear the various parts of your engine vary clearly. Even if you don't have strange noise issues, this is pretty cool.
At any rate, with a little investigative work, you'll be able to pinpoint the noise and make an educated decision as to what it is.
Good luck.
:cheers:
At any rate, with a little investigative work, you'll be able to pinpoint the noise and make an educated decision as to what it is.
Good luck.
:cheers:
Racer
Joined: Aug 2002
Posts: 384
Likes: 6
From: Brockville Ont
Re: Engine Knocking or Exhaust? (flood)
if you can determine which side of the engine the noise is coming from (difficult) pull the plug wires one at a time and see if there is a noticable difference in the noice, if so, could be wrist pin seizing or rod bearing, if not move on to valve train.
Good luck :party:
Just thought of something, make sure you didn't hit something with the pan and dented it, you never know
[Modified by mxzx turbine, 2:41 AM 4/9/2003]
Good luck :party:
Just thought of something, make sure you didn't hit something with the pan and dented it, you never know
[Modified by mxzx turbine, 2:41 AM 4/9/2003]
