I have a 96 5.2 that has been blowing blueish smoke at startup since I've bought it last spring. It also blows a nice cloud after accelerating after idling for a minute or two, either parked or in traffic. The truck burns about a quart of oil every 800 miles. It also doesn't have a catalytic converter so it probably smokes a bit more than it normally would. I've read up on this symptom and the most common problem is the valve seals. Is there anything else common with these trucks that would make it smoke? I'm sick of seeing that damn cloud, and I need to get a cat on it but I want to straighten this out before I get a new cat and immediately clog it up

 

My 96 does the same thing. 200k, timing chain slop noise...Mine has a worn engine I would say. Have you checked compression?

 

Valve seals, oil rings, plenum gasket.

Also, an after market PCV valve can cause increased oil consumption.

From your description, I'd check the plenum gasket (easiest is to, with the motor OFF, remove the throttle body cap and peer down through the throttle body with the throttle held open and a flashlight to see if there's any oily residue visible. If there is, either your PCV valve is stuck open or the gasket is blown; more likely, for these, the gasket blown.)

After that, pick up a Mopar PCV valve and swap that in.

After THAT, valve seals and after THAT, rebuild the motor complete to fix the oil rings *grins*

When you get it to stop smoking, swap that O2 sensor before you even think about a cat; you'd be surprised how much your gas mileage may improve due to the O2 not being plugged up anymore.

RwP

 

Your Mileage May vary....
Here is a method sure to cause arguments but I have used it on two vehicles since being told and it works and the valves seals do get better. noise goes away and less or no smoke comes out.
Drain the oil. Remove the oil filter and drain it then place it back on. Using new oil put half the amount of oil your engine takes to be full in. Then add 1/2 quart of diesel fuel.
Drive it like normal for a couple of hours. the last time I did it I drove for 3 hours and 100+ miles. Drain the oil remove the filter and replace with new filter, fill up as normal with oil.

This helps with valve seals and engine gunk. The guy who told me this has done it for all of his vehicles for years with no problems.

 

I forgot to add that it's throwing code P0441 EVAP system incorrect purge flow. I'll clear the code and it doesn't come back until I idle for a while. Also there's 153k on the truck. I haven't checked compression, I've never worked with engines before but I'll figure out how. RalphP I'll try what you said with the plenum gasket this weekend, hopefully it stops snowing by then!
onemore94dak I've never heard anything like that before. Doesn't seem like it would hurt to try, I'm sure there's a ton of gunk in there. the previous owner did not maintain it at all

 

Replaced pcv valve today and I didn't see any smoke after one trip, hopefully it stays that way

 

well it definitely wasn't the pcv, I just haven't been to willing to troubleshoot the problem now that it's winter. I finally checked for a blown plenum (didn't realize it took 5 seconds to take the throttle body cap off, never worked on engines before) and here's what I saw. What do you guys think?

 

Everyone makes such a huge issue about valve seals like they were expensive or hard to change. They are neither. The main things that you need are a good compression tester (the kind that the gauge snaps to the hose like an air hose fitting would, a valve spring compressor that works on the assembled engine (there are a couple of different ones) and of course access to a good compressor. I can do all 16 valves on a 318 in a couple hours.
for $100 in parts you can do the valve seals, the valve cover gaskets, the plenum gasket and a set of plugs in an afternoon or a couple of nights after work.
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Tomgreene - I bet you've got a blown plenum gasket with it THAT oily!

Pay attention to volaredon - he's got it right there.

RwP

 

Sorry, I typed out a response to this thread a month ago but it never posted! Anyways, I have gotten the Hughes plenum repair kit in the mail a couple days ago. As soon as it gets out of the single digits I'll attempt the plenum repair ( I live in CT). Hopefully that'll get rid of most of the oil consumption, valve seals will be as soon as spring comes and I'm almost out of school. Will update the thread accordingly. I hate unresolved threads😬