Ok, my new to me 2003 has the 4.7L engine with 335K KM on it (over200K miles).. It runs great and has excellent power. It was reasonably well maintained by the previous owner. Here are my issues with the motor:

1. For a lack of better words, the valvetrain clatters (not ticking) when first started, Lasts a couple minutes.and most of the time only does it after an overnight cold start.
2. Occasionally when cold and within the first 3-5 minutes of running there seems to almost be some cam loping as it is not misfiring but you can feel an ever so slight lumpiness to the idle. This only happens after the first cold start of the day.
3 My antifreeze is a wonderful rust filled mess. I am set to tackle this this weekend and plan on adding new hoses and thermostat and such. Any other known issues with an under maintained cooling system?
4. About these heads: in your experiences, do they NEED to be redone and have new seats at higher mileage to prevent issues or are they pretty much a solid working piece unless overheated?

I am trying to weigh all my options. I just bought this truck and I will be doing all the work myself. I simply have not worked on a Chrysler 4.7L engine before. To me, an engine is an engine and they all come apart and go together. I've been a mechanic for almost 30yrs and I have a garage full of tools. My thought is to just pull the heads, send them out, rebuild the timing components and call it a day. Thoughts?

 

The cold start clatter is due to the hydraulic lifters leaking down overnight. Once they refill with oil, they quiet down. Mine sounds like diesel clatter takes about 20 seconds to subside. I run 0W20 full syn for fast cold flow. (Dakota with nearly 300K on original drivetrain)

The cooling system... if it's that much of a mess, run radiator flush through it and make sure you use distilled water if mixing with concentrate to replace. The heater cores can clog if neglected. Pull the heater hoses where they connect to the lines on engine (not at firewall, the aluminum pipes deform way too easy there) and fill that radiator flush. Let it sit for an hour or so and flush/backflush with a tapered water hose nozzle pressed up against the hose ends. Go easy with the water pressure. If the coolant is that bad, you may need to replace the radiator down the line. I'd only redo the heads if needed. See if it's losing coolant or run a chemical block test first.

Don't forget the tranny. It has two filters. Get the OEM spin on filter due to the anti-drainback valve which is lacking in aftermarkets. When you drop the pan, install an aftermarket drain plug in it, or search Advance for the Dorman pan, which includes one.