What causes an engine to burn oil? My 93 burns oil

[exploretex]

My 93 explorer burn about a quart of oil every 3 weeks. The engine has 65k on it. Are there any adjustments that can be made? What would a shop do to fix a oil burning problem? Thanks for the info.

 

[Cameron]

There are several things that can cause oil to enter the combustion chamber. Two of the more common ways are:
Bad oil rings on one or more pistons.
Leaky valve guides.

Unfortunately the only way to fix these problems requires, at a minimum, the removal of your heads. If the problem is leaky piston rings, you need to pull the motor!

There may be other things causing oil to enter the combustion chamber too. Check out this thread:

http://www.explorerforum.com/forums/showthread.php?threadid=23533

Good luck.

 

[Kris Guilbeaux]

explorertex,

Try this first...

Retorque all the bolts on the low intake manifold. My 92 was burnning a qt. every 1000 miles But my lower intake was loose and caused oil to burn this is not the first time this has happened with the 4.0 engine. After I did this my 92 has not burned one drop of oil.

 

[exploretex]

How much is involved in getting to the lower intake manifold? What are the torque specs? I'll take a look at the old Haynes and see what I can find out. Thanks!

 

[exploretex]

Ok I am looking at the Haynes Manual and I see the intake manifold, but I don't see the "Lower" manifold. I see the 8 bolts right on top...are those the ones that need tightening? Which other bolts are there? Thanks

 

[MOTO MIKE]

The bolts you are looking at are the upper manifold bolts, these have to come off to get to one side of the lower manifold, the lower manifold is what the upper one bolts to. Past experience has shown that the valve guide seals are most likely your culprits. These are not too easy to do, but if you have an air compressor that is in fairly good shape, you can change these without pulling the heads, the haynes manual refers to this procedure. nothing is easy to fix, but this is in the most likely to fail and cause your engine to burn oil category.

 

[Bill MacLeod]

You say that it is burning oil. Have you verified this by
taking a compression test, or is there visible blue smoke
out the tail pipe?
Please tell us a little more about this symptons. If it
is fact leaking oil,there may be some fixes that we can
suggest, as Kris has mentioned above.

 

[exploretex]

Thanks for all the responses. Well, I figure its "burning" it and not leaking because I have yet to find a drop of oil on the ground anywhere. The exhaust seems a little smokey. It is actually my Mom's explorer...I drive a Jeep. I am trying to help her with some maintenance. I don't think I am gonna try anything too in depth on the engine, because it's not my vehicle. From what you have told me so far, I at least can walk into the mechanic and let him know I have some idea of possible problems. Thanks.

 

[tshaner]

I would also check the condition of the plugs. If the engine is indeed burning oil, the plugs would show it.
If it is the now famous lower manifold leak, as I suspect my '94 is, you would not be burning oil OR seeing drops on the ground. It would just be 'dissapearing' or so I can gather....

 

[exploretex]

Well, thanks for all of your responses. It appears there is a small oil leak because oil drops have been showing up on the ground. I guess it's a leaky gasket or something. I haven't looked for the location it is leaking from yet, but I assume it's not the lower intake manifold bolts. Then again...it could always be a combination of factors...burning oil and slight leak. The leak is so slow that I don't see how it could lose a quart in 2 weeks of driving...beats me. Thanks again for the responses.

 

[PicoG4]

It could be the lower intake causing a vaccuum leak wich could throw off the pcv

 

[paulreed4]

Nice to know I'm not the only one!

My 98 Explorer Sport 4.0 with 54,000 has started the same. It looks like it's going through a quart every 800 miles or so. I notice smoke when starting after it has been sitting for a while. Not a drop of oil on the driveway. I'm not a great mechanic but it would seem like valve oil seals, or I would think it would smoke more and more often. The idea of loose bolts is intriging. I'm hoping that what ever is wrong is covered under my extended warranty (but they always seem to get out of it somehow).

If anyone has suggestions I'll take them.

P.S. .. I hate my Explorer...

Thanks

 

[Dan Whitaker]

You might check the PVC valve. If it is stuck open it will suck oil in in to the intake. Is the engine rebuilt, or is it original milage. 65,000 is low milage but the age of the valve seals could cause them to shrink or crack.