Greetings,

Just bought this 03 QC with 4.7, 4x4, and 205k miles. Currently running, but very rough. Not really driveable but I did manage to drive it onto the trailer. Located in DFW, TX. Paint is obviously junk, but it's straight, rust free, and only a couple of tiny dings on the bumpers.

It's been a ranch truck for a little while so it's dirty inside but not beyond recovery. Once I get it running it'll be a spare car for occasional home depot run. Eventually I want to be a proper weekend fun truck, and reliable enough for the occasional trip to NM or CO. Mild lift with big tires, bed liner paint job, modern head unit and some custom bed storage.

Anyway, like I said it's running VERY rough. It dies if you lug it down. It died when trying to ease it up the trailer ramps, or even when trying to maneuver it around slowly with a lot of steering angle. The seller claims it overheated hauling some stuff around their property and the issues started after that. In addition to the rough idle it occasionally sounds like it is backfiring, but in the intake if that makes any sense.

Any idea where I should start? For now I just want it running ok if possible, but we're prepared to rebuild if needed.



Thanks.

 

Start with basic maintenance. See what condition various ignition parts are in, or, just flat out replace them. Is the PCM putting out any codes? How old is the gas in the tank?

 

Check plugs and fuel pressure and compression. You can rent (for free) a head gasket tester which sniffs for exhaust gases in the coolant.

 

Does the previous owner know why it over heated? I would guess it may have a blown head gasket by the way you describe it running.

 

They just said they were hauling I mud around the property and overheated. I doubt I would've got a straight answer if I had really pressed. They didnt seem like dishonest people or anything, but I was buying their barely running ranch truck. Fear of the unknown is baked into the price at some point.

We didn't see any oil in the coolant or vice versa but who knows. It's at my father in law's house right now but I'm headed over there this weekend. First thing we'll do is a compression test.

He just rebuilt and flipped a Durango with the 4.7 so he has some injectors laying around that will work. He thinks that's the most likely culprit. I think I fear the head gasket, or worse.

 

Began to get into it today. Did a compression test and had 3 with low compression and one with no compression. FIL says may as well pull it out so we tore it all down and got it to where we'd just have to unbolt the exhaust and transmission next weekend.

FIL decides to pull a valve cover just to see what we can see. Two rockers had popped out from under the cam. This is common on these when a lifter dies. So intake on cylinder 2 wasn't opening which is why we saw no compression. We're going to replace all the lifters and slap it back together enough to see how it runs

Where's the best place to buy new lifters, or anywhere I should stay away from?

 

rockauto.com has good prices buy oem mopar if you can afford it if not sealed power or melling should be ok. These engines need full synthetic or those lifters get mucked up and toss rockers like yours did.

 

Hart, where are you located? l'm on the southside of cowtown. I have a DRB3 for doing factory module parameter changing and other fancy things.

"mild lift" with the 4x4 is a little more difficult with the 00+ rack and pinion, all the kit kits are for 99- steering box. But there are some tricks with the torsion bar keys to get another inch or two-ish.

The 4.7 is an odd animal. Knowing that it knocked some of the rockers off, I would cycle out the lifters for sure, but that would worry me on how sludged up the engine might be. It might not be a bad idea to run some seafoam and/or MMO through the oiling system and see exactly what you have to work with.

 

I suppose whether I can afford it depends on if it's really worth it. Currently it's $300 for Mopar vs $112 for the Sealed Power. I don't mind spending it, but how much better can it really be?

 

I'm in the mid-cities. I was just looking at the ride height today and it might be fine already. We'll see. It looks pretty level and they have 265-70-16s on it. Is that the factory size? I could go with a little bigger/wider tire and probably be happy.