What Could Be Causing a Ticking Noise in My 2008 Mustang 4.6 3V?

Ford Models Ford Mustang Club
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Hey, everyone, I’ve got a 2008 Mustang 4.6 3V that’s developed a ticking noise near the rear intake manifold. So far, I’ve replaced the oil pump, timing chain, all lifters, rocker arms, new phasers, and VTS, plus the cams look good. The ticking is much louder on the driver side, near the back of the intake, but not as noticeable on the valve covers. I’m stumped. Anyone have any suggestions? :pray:

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Hey, @Unclewaffl3s ? That ticking sound you’re describing, especially being louder near the driver side rear of the intake, might be worth checking for exhaust manifold leaks or cracks. Sometimes an exhaust leak can sound a lot like a valve train issue, especially under load or when accelerating. A small crack or loose bolt could be the culprit🔧

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Thanks for the tip, @Dolph I’ll check the exhaust manifold next. The space between the manifold and the transmission is super tight, so it’s been hard to get a good look.

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Yeah, that area can be a real pain to inspect. Since it’s so tight, you might want to try an old-school trick, use a piece of hose or a mechanic’s stethoscope to listen closely. It could help pinpoint if there’s a leak in the exhaust or a vacuum leak that’s hard to spot.

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Good idea. I’ll grab a stethoscope today and give it a shot. :crossed_fingers: Thanks again

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No problem. Let me know how it goes

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Alright, I used the stethoscope, and the ticking is the loudest around cylinder 8. I also plugged the driver side tailpipe, and weirdly enough, there was no pressure pushing it out like on the passenger side. After disconnecting the #8 injector, the ticking completely stopped, and the engine still idles smoothly even when the tailpipe’s blocked. Looks like I might need to pull the exhaust manifold. :grimacing:

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Wow, nice detective work. The fact that the ticking stopped when you disconnected the #8 injector suggests the issue is tied to that cylinder. Sounds like you’re dealing with a potential exhaust manifold leak near cylinder 8. If there’s a small crack or gap, it might only show up under load.

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If you’re up for it, pulling the manifold could reveal more. Look for cracks or exhaust soot, it could show where the leak is. Once you re-seal or replace the manifold, that should take care of the ticking. You’re getting really close to solving this :wrench::muscle:

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Thanks, man. I’m starting on the driver side exhaust now. It’s gonna take a bit, but I’ll keep you posted😅

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Sounds good. You’ve got this. Let me know if you run into any issues along the way.