Valve spring problem

Tiny
MIKE LUCKEY
  • MEMBER
  • 1998 BUICK CENTURY
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 177,000 MILES
Hi, my car started misfiring and shut off. I checked for spark, all good. So I checked compression, had three cylinders around 180, two cylinders 120 and one (number six) with 0. Thinking possible broken valve spring. Just wondering with the compression being so different, should I even bother fooling around with it. Any help would be appreciated, thank you!
Friday, March 23rd, 2018 AT 7:51 AM

5 Replies

Tiny
PATENTED_REPAIR_PRO
  • MECHANIC
  • 1,853 POSTS
Yes, I would go ahead and remove the valve cover and see if anything is obvious.
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Friday, March 23rd, 2018 AT 7:55 AM
Tiny
MIKE LUCKEY
  • MEMBER
  • 38 POSTS
I sure will, just wondering, if the compression is so different on the other cylinders is the engine even worth working on? Btw, the compression test was done on a cold engine, because it wouldn't start. Thank you, Mike.
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Friday, March 23rd, 2018 AT 11:12 AM
Tiny
PATENTED_REPAIR_PRO
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I would not commit to any work just yet, just diagnosis. You might also consider a cylinder leakdown test on the cylinders that were low to determine where the loss of compression is coming from.
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Friday, March 23rd, 2018 AT 11:27 AM
Tiny
MIKE LUCKEY
  • MEMBER
  • 38 POSTS
Okay, so I pulled the valve cover and no apparent broken springs. I decided to turn the engine over with a wrench on the crank pulley. The rocker arms do not move! I am assuming this means a broken timing chain? It does not make any weird noise when it turns over though. Would it not sound pretty bad if a timing chain were broken in there? Also, is it an interference engine? Could I have bent valves too?
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Friday, March 23rd, 2018 AT 6:41 PM
Tiny
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I am wondering how you got any compression readings at all if the timing chain was broken.
Did you remove both valve covers and check the other side, too?
I do not think the 3.1 is a interference engine.
I assume you could have landed on a cylinder that had both valves closed when doing the compression test.
I am getting conflicting results on whether or not it is an interference engine. I have always thought the interference engines could only be ones with a timing belt, but I could be wrong.
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Saturday, March 24th, 2018 AT 7:44 AM

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