Hey Everybody, see if you can help me on this one. I have a 94 Explorer XLT 4x4 with 129,000 miles. Recently, within the last 10,000 miles or so it consumes a quart of oil every 500-700 miles or so. The strange thing is it starts right up, there is no smoke, but the exhaust pipe has black soot all over the end of it and inside of it. I had a rocker shaft mounting bolt on each side of the engine break last year and had to replace the assembly, pushrods and bolts and everything was tightened to specs. Both sides were done because they went within a few weeks of each other. My mechanic said he never had seen anything like it before. I run 5W30 in it which is what is recommended. There are no leaks that I can see and the thing runs great except for pinging like most of them do. Could there be a valve sticking or something. According to the oil pressure gauge it is dead center on the normal area. When I start it, it will sometimes tap until it is warmed up and other times it won't do it. Please let me know of anything that might be causing this. I am getting tired of putting oil in it. Its strange because I change the oil religiously at 3000 miles and maintain everything. I need to change my fuel filter but besides that everything is up to date. Please post any ideas you may have. Thank you and have a great day

 

Welcome to FTE!!

A few thoughts on the oil consumption:

*need for new PCV valve
*failing lower intake manifold gasket which allows some oil to be drawn in and burned while driving. By chance is just one spark plug showing evidence of oil being burned? How do the plugs in general look?
*when you had rocker arm issues, any chance metal shavings got in the engine and had a chance to circulate around for awhile?
*have you done a compression test?

On the pinging, it's not correct to say that most of them do. There are three very common reasons for the 4.0 to ping and all are quite simple to address. Most people with the ping issue just don't know the simple cures. They are (in no particular order):

*dirty MAF sensor (a freebie if you do it yourself)
*engine needs to be decarboned (around $30 in parts if you do it yourself)
*the lower intake manifold bolts need to be retorqued (note my second pointer in the last section). But usually the loose bolts produce a vacuum leak on one cylinder, it runs lean and therefore hot on that cylinder, and thus the ping. Once again, freebie if you do it yourself.

Now a word on the oil pressure gauge. It's not a real gauge in the sense of reflecting actual oil pressure, but rather it's an "idiot" gauge. When the oil pressure is at about 7 psi or greater, the oil pressure sender is a switch that is activated and by design is supposed to make the gauge read midway. It's really just an on/off gauge in place of a light .

My suggestion at this point (oil consumption) would be to retorque the lower intake manifold to the proper torque specs. It's a freebie if you do it yourself and may just end the problem (and maybe two problems). The ping is not to difficult to address; decarboning and cleaning the MAF sensor are discussed in the Ranger forum under a sticky titled technical information. All of these items are within the ability of an average weekend mechanic; no surprises lurking here. I'm also not yet convinced that your engine is tired; I've got 180,040 on my Ranger 4.0 and it does not use oil between changes.

Hope this answers a few questions and give ya some food for thought.

 

Welcome to FTE!

In addition to the points that Bill raised, be 100% sure that there is no external oil leakage. Keep in mind that the absence of a puddle on ground doesn't always mean that there is nothing leaking. Check the underside of the engine completely, best time would be after it is driven for a while and is nice and warm.

Other internal issues that could cause excessive oil consumption are worn main and rod bearings (allowing too much oil to be "thrown off" and up into the cylinders) as well as worn valve stems seals and guides (intake manifold vacuum draws oil and oil vapor between the intake valve stems and guides where it is distributed into the cylinders and burned).

 

Thanks for the info everybody. I'll get to it as soon as possible. What could be causing the black soot in the exhaust pipe and on the end. I'm figuring it has something to do with the oil consumption problem??
Thanks