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2012 engine sounds noisy/rattley

2K views 8 replies 7 participants last post by  egads 
#1 ·
Hi all- About a year ago my engine (which has about 115K miles on it) started being noisy upon startup but would typically quiet down as the engine warmed up.

I took it to my Honda dealer to have it diagnosed, but the service technician could not hear anything unusual even after leaving with him for a day to cool down before starting. Of course.

Now about a year later, the sound has progressed to be a bit louder and be more frequent. Does not sound good.

I would expect it may need a valve adjustment but wanted input from others in this forum who may have experienced the same thing.

Anyone had the same experience?
 
#3 ·
115K would be on the low side to have noisy valves, but it's possible.

Could you listen with the hood open to identify the general area of the noise? Left or right? Front or back?

How would you describe the frequency of the noise relative to engine idle speed? Same, slower, faster?

Dave
 
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#4 · (Edited)
I had a cold start rattle too on my 2013 EX-L with 74,000 miles. It was not valve noise!

It ended up being a Timing Belt Tensioner failure.

The fluid inside the tensioner leaked out and caused the tensioner to rattle against the tensioner pivot landing. The piston in the tensionor temporarily seizes when cold.

If you search the community threads for “ Cold Start Rattle” or “Timing Belt Tensioner”, you will see that it is a common problem with the hydraulic tensioners used on the honda V6’s dating back to the previous generation too.

They seem to go bad around the 5 year/100k mile time period.
 
#5 ·
I agree, it sounds exactly like a failing TB tensioner. Search on here for troubleshooting steps. The key clue is that it is loud at startup and gets quieter as things warm up.

BTW, at 115k miles, I'll guess you already had your TB service done. And I'll also guess that maybe the TB tensioner was not replaced as part of the work. Replacing that part or not is a common thing to skip to save a little on the cost. People who do the work themselves generally replace it since it's not too expensive. But it seems that professionals, especially dealers, will leave that item off the job to allow them to offer a lower price to a consumer who may not know what they're missing out on. And then also, there's a chance you were billed for the replacement, but it was not replaced.
 
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