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05 STS N* RWD
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7 Posts
Discussion Starter · #1 ·
Hello, just bought an 05 STS N* V-8. It has 86,000 mi and it has a very light tapping noise at idle and on acceleration. Under load, it seems to lessen in between shifts and under heavy acceleration. The sound is like a lifter tap on a push-rod engine. Any thoughts would be appreciated. Thanks
 

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2007 Cadillac STS
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182 Posts
If its a tapping noise it could be a hyraulic valve adjuster. Where is the sound coming from exactly? Its hard to diagnose a sound with out actually listening to the vehicle.
 

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2006 STS 1SG & 2007 STS 1SE
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21 Posts
There are a lot of quieter engines than the N*. There's probably no real problem. There are a lot of things that can tick.

Use the old hose trick if you can't isolate the location of the noise. Take a length of garden hose (2 feet?) and listen to one end while probing with the other.
 

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2014 XTS V-Sport Platinum
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2,431 Posts
Mine ticks a bit after a cold start, but gets much quieter after it has warmed up. I agree with the fresh Mobil 1 change idea...can't hurt.
 

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2008 STS-V and 2003 Escalade, 2005 STS4 1sg (sold)
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36 Posts
Mine has a ticking noise too at idle mostly but when I asked the mechanic he said that most sts's that he works on has the same noise and told me not to worry about it
 

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Cadillac Owners Troll
2019 CT6 Sport 3.0TT,2015 Luxury ATS , 2016 ELR, and Volt
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2,464 Posts
Does your car still have the engine cover on it? Many people assume it's just a beauty cover but the injectors and EGR valve make a lot of ticking noise.
 
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