My 2004 6.0 L is making a strange popping noise that seems to be coming directly from the intake line to the turbo (i.e. air filter). It is not a metalic knocking or pounding, instead it almost sounds like an intake valve stuck open or something and it is popping back through the intake. Popping is the best word I can come up with to describe it. A couple of guys with a shop near mine listened to it and they thought that description seemed the best they could think of also. They also felt it didn't sound mechanical like a knock. The engine runs fine except for a regular miss on one cylinder. If I turn it over with the injector relay unplugged it sounds like reduced compression on one cylinder. In other words the rpm seems to jump a bit in a regular pattern as that cyl comes around. The truck had recent head gaskets, ARP studs, new oil cooler, EGR bypass, HP oil rail plug upgrade etc. Then it started doing this suddenly. Any ideas on what I might check out to figure out what it is? I have a brief video but I don't see how to attach it. Help? Ideas? Suggestions?

 

I put the video here:

https://vimeo.com/107212652

 

Head gasket leak past the fire ring to the next cylinder. That's my diagnoses with the little bit of info and no hands on. I'd try to narrow it down to what offending cylinder is causing it. Unplug one injector plug at a time then start it and see which cylinder you stop hearing it. This should be the cylinder that's "bleeding over" to the other cylinder and huffing through the intake. Write back your results.
Either poor prep, warped/cracked head, uneven improper torque sequence are just a few causes.

 

Sounds like a valve train issue to me, broken valve spring, rocker bridge, or bent pushrod.

 

Pull valve covers and inspect. My little brothers truck just had the same issue and it turned out to be a rocker arm.

 

What he said^^^^

That is indeed a very disturbing noise...I was eating breakfast and literally stopped chewing as soon as I heard the noise. Don't drive the truck, please get it fixed.

 

X2. One of these.

 

OK I will pull the valve covers and see if I can see anything wrong in the valve train. I will report back. If it is a bad rocker or push rod can I replace one of those without the head coming off?

 

yes...........

 

OK. It seems like I remember the rocker assembly base is under the head stud nut with two small bolts on either side. That is why I asked. Well I'll open it up this evening and we shall see what's wrong (I hope). Thanks for all the help and advice gents! I appreciate it.

Maxi

 

my guess is failed rocker arm shaft

 

Update. Boy you gents zero'd right in on the problem. Valve train. I pulled the driver's side valve cover off along with the HP oil rail, up pipe, dummy plug etc. Sure enough it looks to me like the exhaust push rod on the second cyl back from the front (is that #2 on these?) is bent. It is pushed up against the side of the bore it goes through in the rocker box at about 10 o'clock. Here is a quick video:

https://vimeo.com/107309456

Looks bent right?

Kind of hard to see but if you look close I think that you can likely see what I am talking about. All the rocker assemblies on that side look fine. The rest of the push rods also look to be centered up just fine. Everything was carefully marked and indexed when it came apart and it all went back where it came from, in the orientation that it came out. So I am assuming I just need to replace this one set of push rods right? So can anyone offer some help with a few questions please?

1) Will my Ford dealer sell me just one or two push rods or am I going to have to get a set? Or can I order just a couple from somewhere online?
2) Is there anything else I should be checking or doing while I have things this far apart? Remember from my first post I just did the upgraded up pipe and dummy plug replacement, ARP studs, head gaskets, EGR etc. What else should I check so I don't damage or bend another push rod or anything else?

Thanks again for the help everyone. That loud noise from under the hood all of a sudden when I went to start the truck and head out the other morning was very unnerving. If it turns out to be just a bent push rod that is a whole lot better than what I feared given how loud it was.

Maxi

 

You can replace just the one pushrod. However, it wouldn't hurt to pull a few and check them straight.
You can buy them in singles but a good upgrade would be to replace them all with 6.4 pushrods.

Glad you found the problem

 

You will need this tool to replace them.

This tool is less here. But I think you also get charged shipping.
https://rotunda.service-solutions.co...x?itemID=18452

So I put the Ebay one up also.

http://www.ebay.com/itm/New-Rocker-Arm-Release-Tool-303-1170-Fast-Shipping-/181382376267?hash=item2a3b3b6b4b&item=181382376267&pt=Motors_Automotive_Tools&vxp=mtr

Then take the removed push rods and rool then on a sheet of glass. if you hear a tick,tick
that that one is bent. If they are quiet that you good.

Sean

 

Pay very close attention to the rocker arms.

Happened to me once didn't look close enough at the rocker arm put it all back together rocker arm then completely broke and I was doing the job twice for not paying attention properly.