I have a 2002 Ram 1500 4.7 and I have this extremely loud knocking sound that is steady with the rotation of the engine. My check engine light is on and AutoZone says its the number 7 cylinder misfire. The knocking sound will fade with the sound of the engine/exhaust but is still there. My mechanic and i are completely stumped on this. The head gasket is fine, the oil level is perfect, and we have removed the valve covers and inspected the rocker arms and they all appear to working properly. I am also getting engine oil blown back into the air intake and after i shut off the truck, I take the oil cap off and it smells like a fuel/oil mix. My mechanic suggests engine replacement but that's a lot of money I don't want to spend if it's not needed. I've also contact 3 mechanics around town that won't touch that engine for rebuild. I'm basically trying to get ideas of what it is a..and b what my options are.

 

Well if oil is getting blown back through the intake then either the PCV valve isnt working or you have some really bad oil rings and on the pistons and letting oil get by. Rebuilding a 4.7 is no more hard that building any other engine. Either they dont have the skills or they dont have the time.

4.7s can easily develop issues around the side of the engine from overheating a bit. The heads either get cracks in them or the head gaskets blow and leak. You say the head gaskets are ok but what was dont to actually check them?

 

A blown head gasket on a vehicle that's not even 10 years old? It wasn't made in China so I would think it's not a blown head gasket. Maybe if your truck was a 1990. Sounds like a bad EGR valve.

 

blowing a head gasket has nothing to do with age and you need to do some reading about the 4.7s as one of their weaknesses are the head gaskets and heads

 

My 02 4.7 knocked and had oil coming out of the air intake. Once I took the head off, I could move the piston with my hand. It was beat up and it beat the head up too. Pretty sure I broke a rod, but I still haven't looked for sure since I've spending time on an engine swap.

How many miles on this thing?

 

try and listen if the knocking is coming from oil pan area or valve cover area. that will give you a gist of area. ive seen rods and rod bearings go on them and also cam towers crack where the rocker arm assembly meets the head. (the cylinder head itself cracks that holds the rocker assembly.)

 

with a 4.7, all I can really do is extend my condolences.. I have a 5.9, and I'd actually rather have mine than yours.. those 4.7s are- well anyway:

all the issues that engine has with hydraulic lash adjuster, rockers, timing chains, heads in general, head gaskets, gunking up, spinning bearings, blah, blah- this, to me doesn't sound like what's happening to you..

PCV valves can make a LOT of noise believe it or not, and they can really let a LOT of oil past.. idle your engine and grab a hold that rascal, and see if it is the source of your noise..

 

And unless you're a master mechanic (Even if you are) that's the worst situation you can encounter with an engine for the most part. It doesn't get much worse then a blown head gasket.

 

It's a hassle, but it can definitely be a lot worse than a head gasket.

 

Yeah, like throwing a rod or spinning some bearings. Then you are looking at a full rebuild or replacement. Replacing a head gasket is nothing if you have the knowledge and proper tools. Trust me, Ive custom built and rebuilt more than a few engines. You dont have to me a master mechanic. You need knowledge and tools. Money helps too though.