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I have a 2010 Mustang GT with 4.6L engine that started making a ticking sound which at times is fairly loud. The sound is much less obvious at cold start but becomes apparent after it gets hot. The sound is loud enough to be heard with windows closed inside the drivers compartment.

The clicking/ticking sound appeared to be coming from the drivers side valve cover, so I assumed as most of these engines that it was the cam phasers or a cam phaser solenoid that went bad. I changed out the phasers, timing chains, gears, chain guides, plungers, and solenoids but didn't change out the oil pump.

The noise remained after that work. But I took these pictures looking down at the valves. The black and charred looking valve in the picture is the valve that is closest to the driver. I believe it's one of the exhaust valves for that cylinder.

What does it look like happened? Burned or stuck open valve? I haven't put an oil pressure gauge on it, but I plan to this weekend, or am I pretty much assured of needing to remove the head?

The car has a slight hesitation on throttle up, and the hesitations seems to pulsate as if the solenoids were trying to move the cam phasers but can't get them to move enough. So that's why I now think the oil pressure might be too low. But is it too late for that head?

View of the valves

Alternate view

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    You don't really show us what the cam lobe looks like. This is 1/2 the story here. If it's in bad shape, it could be the roller in the rocker has seized and then the heat buildup has fried the rocker. Cannot tell the shape of the cam lobe, so I couldn't tell you for sure. Looking at some of the other cam lobes, they don't look too healthy. For instance, the two just below the beige connector does not look very good to me. You'd have to get a measurement on the cam with a dial gauge to see if it's within spec. I'd use this method to check over pulling it all apart. – Pᴀᴜʟsᴛᴇʀ2 Apr 10 '17 at 23:01
  • @Pᴀᴜʟsᴛᴇʀ2 that's exactly what happened. New cam, rocker and lash adjuster ordered. I'm not sure if I shouldn't just replace all of the rockers and lash adjusters while it's open. I might as well. – mark b May 22 '17 at 17:53
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I think I'd first be doing a compression test here just to help perhaps rule out an internal engine problem like a burnt valve etc. Assuming pressures are good though... I'd then be considering pulling the cylinder head to properly see what's going on in that area.

Not only does the lifter looked gummed-up but that rear cam bearing housing looks like it's been getting hot too, so you're going to have to check the camshaft & bearing back there anyway.

I think you may be correct in that there is an oil pressure problem here, OR there is a blockage in this area which has allowed these black components to become hot enough to bake the oil, hopefully it's not affected the cam lobes and bearing surfaces though. I'm just concerned that the back end of that head area looks rather dry.

Hopefully though the camshaft and cyl head etc will be ok.

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Here's what happened to the engine in this case as found when I tore into it:

That roller on that burnt looking rocker arm locked up. It wouldn't turn any more. So it overheated and also dug a lot of metal out of the camshaft.

New camshaft, new rocker arm, and new lash adjuster ordered.

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