Valve spring problem

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!

5 Replies

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

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

PATENTED_REPAIR_PRO

MECHANIC
1,853 POSTS

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

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

PATENTED_REPAIR_PRO

MECHANIC
1,853 POSTS

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.