Hi folks,

I went to work one day and when I left (about 8 hours later) I started my engine and heard a fairly loud tick/tap. Since then I’ve noticed a few things:
• It was loudest when the engine is cold (as cold as it can be in the summer), but seems to subside after the first 5 minutes of warming up. It almost goes away, sometimes I’m convinced it is gone until I start it up cold again.
• It seems to be coming from cylinder #8 (rear, passenger side).
• If I disconnect the fuel injector for that cylinder it seems to go away. However, as a test I took some clip-leads and energized the fuel injector manually and compared it to the cylinder next to it and they sounded the same – I did this cold.
• I tried running a tank of fuel injector cleaner, didn’t seem to help.

Any idea what this could be? Do you think it’s carbon build-up? Kind of strange that it came on fairly suddenly, and subsides after warm-up.

Any clues would be appreciated!

Thanks

-John

 

See my reply over at the DOC in your thread there John.

IndyD

 

any ticking sound like that is 101% a leaking exhaust manifold - it just gets warm and expands to fill the leak so it goes away. i had this problem and thought it was tappets - don't let anyone tell you anything else, its the exhaust mainfold, trust me. i suggest you get the garage to do it since there is a high probability that at least one of the bolts will shear off when its removed. if you're really unlucky, then it will also have warped like mine...Chris

 

^ Yep ^

 

Guys, you’re spot on, I believe it’s an exhaust leak. I do have a broken bolt on cylinder #8 which would be consistent with it going away when I disconnected that injector.
Now, how long can I drive on a broken bolt because I have a vacation coming up and I’m not sure I can get a dealer to fix it before then (I’m not going to torture myself with this one). What’s the risk in waiting too long to fix it (and how long is ‘too long’, week, month, year…)?

-John

 

It's ok to do it when you get back. You'll have to remove the manifold to get the bolt out. Most of the time it breaks just the head off and you can take the manifold off including the exhaust O ring so the whole thing comes off and get a pair of chanel locks or small pipe wrench and turn it out. If it's broken in farther then you might have to drill a small hole in it and use an ez out.

Replacement is grade 8 heat treated bolts or at least grade 5.

 

+1 on Grade 8 or better (specialized manifold bolts.) I wouldn't mess with Grade 5s.

IndyDurango