1998 Chevy Lumina Chevy Lumina 1998 3.1L Knocking when pres

Tiny
JWALLACE79
  • MEMBER
  • 1998 CHEVROLET LUMINA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 195,000 MILES
Hi all, I hope you can point me in the right direction.

I have a 1998 Chevy Lumina 3.1L, with 195,000 miles (a real mule). I had some pretty significant engine work done about 10 months ago involving the coolant system and valve cover gasket, as well as a replacement of two wires causing engine misfire. Drove fine for awhile, in fact quite well through this past autumn. About two months ago, the service engine soon light came on, but no noticable problem. A month later, I noticed a low banging sound, like a clanging noise that was more pronounced when pressing the gas. No pattern to it, just like something's banging around the inside, I can feel a bit of vibration under my left foot from it. There's no discernable suffering of performance, the gears change smoothly, gas mileage is about the same as it always was, but this damn noise and it's been getting worse (and louder) each week. I'm trying to avoid a code check before I have a broad idea of what's wrong (I'll just junk the car if necessary). Any idea what this might be?
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Tuesday, February 3rd, 2009 AT 10:55 AM

4 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi:
As far as the banging, make sure there isn't a broken motor or trans mount. If you need directions, let me know. The check engine light can be checked for free at most nationally recognized parts stores. Just ask them to scan the computer for codes and reset the light.

Let me know what they find, and if you have questions on testing motor mounts.

Joe
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Thursday, February 5th, 2009 AT 3:22 PM
Tiny
JWALLACE79
  • MEMBER
Thanks a lot for the tips! Actually I would appreciate any tips you have on checking for these mounts, or at least have a ballpark figure for how much it would cost to check this out. Like I said before, it only makes the bang/knock sound when I give it some gas, but there isn't any discernable performance or shifting issue. This makes me worry about a CV or U joint, but I'm pretty novice so I may have just sounded like a moron.

Thanks again, I hope to hear back.
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Thursday, February 5th, 2009 AT 3:48 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi: I'm glad to help, and no the CV joints can make a noise if they get really bad. When they start to go, you will hear a clicking sound on sharp turns. So no, I don't think you're a moron. LOL

As far as testing mounts you will need a helper. Open the hood of the car and start the engine. Place the e-brake on and have your helper hold his / her foot securely on the brake. Now have him put the trans in drive and press slightly on the gas making sure the car doesn't move. While this is happening, watch the engine. If there is a broken mount, one side of the engine will lift up and when the gas is released, it will drop back down. Try it in reverse too. The opposite side of the engine will lift if that mount is broken. NOTE: It is normal for the motor to move slightly. More than an inch is excessive and either a mount is worn or broken.

Let me know what you find, and please don't stand in front of the car when your helper is running the engine. You never know (if they are mad at you) when their foot can slip off the brake. LOL

Let me know.

Joe
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Thursday, February 5th, 2009 AT 7:03 PM
Tiny
JWALLACE79
  • MEMBER
Joe,

This is really quite a clever test. I'm going to give this a shot this weekend and I'll make sure to post back here and let you know.

Thanks again:)
Jake
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Thursday, February 5th, 2009 AT 8:56 PM

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