Bought a support truck to hold me over while I do some major re-work on the Ram, trans rebuild, transfer case etc... & possibly an engine rebuild down the road.

What I got is a 2002 QC 4wd with the 4.7 motor. It has a bad rear end, sounds like the posi setup has an issue as it makes noise on tight turns. Planning to just swap out the axle and be done with it. Has some other minor issues but overall runs pretty good and the body is near mint for a 2002. I am not a fan of the 4.7 motor, would have preferred the 5.9 for its simplicity and durability. Unfortunately anything with a 5.9 gasser is snatched up quick. this one I got pretty cheap and feel I can get the $ back out of it when I'm done.

Question I have though is, What on this motor do I need to address asap?

the PO stated he had both head gaskets done back in 2019, not sure if anything was done with the chains, my bet is no. I am aware of the sludge issues with these motors, had a 2000 QC 4wd years back so not 100% new to it. My plan is to add in/swap 1 quart of stiction eliminator into the crank case (oil was swapped not long ago and looks good) and monitor the fill cap for increasing sludge indicators.

also, it has a small evap leak code. going to build a smoke generator and see if I can find it (have all the parts already). Will be running sea foam thru fuel as well. Will eventually swap out all the fluids for fresh and know where I stand before relying on it heavily.

Anyways, a lot said so I'll stop here for now. Thoughts?

 

Sounds nice. Typically "small evap leak" code means the gas cap is either not tight or has a leak. On the rear, it may be as simple as needing a fluid change. Some posi units, at least in the GM world, require a specific additive to work correctly, and the wrong fluid makes them act up. A fluid change and any Dodge-required additives would be my first step before replacing the rear. At worst you'd be out 30 bucks on diff oil and additive. Sorry, don't know much about the 4.7 other than it's a bear to set the timing chains up correctly, my Dakota came with a 3.9L.

 

I've dealt with small evap leak. Usually the under hood hoses and those underneath by the gas tank are cracked and leaking by now. Squeeze every inch of them and look for cracks, especially near the ends. If you find any, cut off and reattach Some hoses run under the battery tray too. I greatly reduced the frequency of the codes by eliminating the leaks, but they didn't completely disappear till I replaced the leak detection pump, which is underneath the truck, roughly below the driver's seat. The pumps are shared among many dodge vehicles.... I got mine from an 09' junkyard PT cruiser.

The 4.7L will last you a very long time with basic maintenance. By this I mean simply keeping the oil and coolant topped up. Try to never overheat it. I wouldn't run anything but full synthetic (I use 0W20). I'm still on the original chains at 325K. Original motor and tranny too (no rebuilds). Heck, even the starter is original. Most work I've ever done was replacing lifters at 300K when one finally failed and kicked out a rocker. She drives better and better as the years go by. I've driven much newer trucks that are not even close to how this one feels.

The fill cap is not really a good indicator of sludge on these engine. They tend develop a yellow goo underneath, especially in the winter. This is due to them sitting so far up off the engine that oil mist/vapors tend to cool and coagulate in the fill cone. This one in the pic is pretty bad (random internet pic), but this and smaller oil passages is why I'd never run a cooler thermostat or conventional oil.

What do you need to address? Well, these things will make themselves known as you drive. Just keep checking the oil and coolant level till you figure out if you have any leaks, etc.

 

Thanks for that info on the EVAP leaks!! I have the parts to make a smoke generator and plan to use that first to see what shows up. When I pulled the cap there was minimal sludge at the cap but it did have some. Nothing like what that pic shows. The last 4.7 Dak I had showed way more than what I have on the current motor but no where near what the pic shows.

I got the dak rolled into the garage last night and will pop off the rear diff cover soon to have a look (doing a deep cleaning on the Ram atm... same one from way back in 2006 with 465k on it now), will see if I can get to the rear diff tonight.

One thing I noticed on the drive home was the oil gauge was fluctuating off of being just above the lower end of the OK scale to half way to half scale (if that makes sense). I would not be surprised if the oil pickup screen has gunk in it so I am planning to soak the pan with a yet to be determined cleaner to dissolve anything that might be on it. Meaning, dump the oil, fill up the pan thru the dipstick tube and let it soak for a few days, then dump and fill with a cheap oil for a few drain & flushes (with heat cycling the motor). Will use the stiction eliminator in there with the synthetic oil & new filter when done and convinced the internals are not dumping anything additional out of the pan.

so the current plan is:

1) pop the rear diff cover and inspect
2) fill rear diff up with fresh oil and test drive
3) drain oil out of engine pan & drop in the yet to be determined cleaner and let it soak
4) drain & fill with cheap oil until happy
5) final fill with royal purple, most likely 10w-30 hps

Thanks for the input! I will post updates here if anyone is interested in seeing how it goes.

 

Pics...

 

Nice looking truck! Don't run 10W30... it makes no sense to have thick oil on start up, when the most wear occurs. At operating temp, it's the same as 5W30. Chrysler has been using 20 weight as standard fill on the 4.7s for many years. My oil pressure is perfectly fine with 0W20 and I'm getting less restrictive oil flow.

 

I've never been a fan of the lighter weight oils, your saying to use the 0w20?

Did DC go to a lighter weight oil for a specific reason?

 

All manufs have moved to lower viscosity oils for multiple reasons, including slightly better gas mileage, smaller oil galleys, higher performing sythetics. Better flow on start up is my biggest reason. Listen to your 4.7 at cold start. If you're hearing that "diesel" clatter, it's the lifters waiting to prime with oil.... you want that to happen fast or you eventually lose rockers. Chrysler first specified 5W30 for the 4.7L then shifted to 5W20. I run 0W20 because it flows faster at start up. At full temp, a 20 weight is a 20 weight, so 0W20 and 5W20 are the same after warmup. I've also tested oil pressure with gauge and it's good (with 0W20). 10W30 is thicker at startup, then turns into the same viscosity as 5W30, so you might as well run that. I've scoped my cylinders and hatch marks are still there.

Don't want to turn this into an oil thread. When you've got time.... https://540ratblog.wordpress.com/201...-test-ranking/

 

update, started flushing the motor, swapped a known good gas cap seal onto gas cap, cleared code and serviced the rear diff.

rear diff now dead quiet over the 10+ miles i drove it to get it warmed up... will monitor further once i i am done with the motor flush. if it is good, will dump fluid again, pull cover and clean it all out real well before premium fluid refill.

 

Pics of my first 4.7 QC... Have some pics somewhere of Jr & I "wheeling" in the dry lake bed, that was a fun day. Jr loved that truck.