Magical disappearing oil

[brokemechanic3000]

Hi guys I checked my oil today and it was 3qts low! it never lost that much oil before. usually 1/2 qt on oil changes every 4,000 miles. It was too dark out to check for a leak, I will check it out after work tomorrow. It isn't burning it no smoke out the tail pipe.
I'm hoping that I just need to check the pan bolts (seen that on other vehicles be the problem).
Any thoughts on what it might be or what to look for ?

 

[McCormack]

After you park your truck for the evening put a piece of cardboard under the truck, and if you have an oil leak you'll be able to in the morning see on the cardboard the location of the leak.

 

[brokemechanic3000]

No leaks on the ground, I would have noticed a puddle from losing 3 quarts. I checked it out at work made sure the oil pan bolts were tight also checked valve cover bolts a few were loose. I noticed that my butterfly valve was dirty could it be coming from the tube that goes from the oil filler neck to the air intake. PCV valve? coolant is nice and green no visible leaks from outside except for normal weepage.

 

[McCormack]

Oh OK, you haven't noticed any obvious leaks.

If you've got an EGR valve on your 3.0 then that's the likely cause of your dirty butterfly valve.

A plugged PVC valve could theoretically be letting pressure build up in the crankcase forcing oil past the the rings/valve guides. You'd have to pull the PVC to see if it's plugged.

If it's not then about the only other answer is that your rings and/or valve guides are worn, and a compression check would be in order.

 

[brokemechanic3000]

Thanks, I already ordered a new PCV valve will be putting it in next week.
and I will have to check the EGR valve.

 

[McCormack]

The EGR's (Exhaust Gas Recirculation) job is to divert exhaust gases into the fresh intake charge in order to supposedly reduce nitrogen oxide levels, so if your butterfly is blackish and sooty then that's normal and your EGR is doing it's job.

 

[brokemechanic3000]

Thanks but I will still check it anyway. Just alarmed that 3 qts disappeared in 2500 miles spark plugs are clean. but having vacuum hub issues now. Figures I just paid it off last week now everything is breaking.

 

[McCormack]

Figures I just paid it off last week now everything is breaking.

I feel your pain, lol.

 

[buckshotmudder]

What may seem not normal for others seems normal to me for a 12 year-old engine. You imply you ran 2500 miles, and you were down 3 qts. so that works out to about 1 qt. consumed every 850 miles.

My 91 3.0 consumes a qt around 800-900 miles. Is that normal? Would others think its normal? I have 300k+ miles and a small leak and my engine oil consumption seems normal to me.

 

[locovaca]

1 quart every 3000 miles is the threshold I consider "normal."

 

[elcaliente]

lots of things, valve cover gaskets/ bolts need tweaking, is your overflow tank black? oil gets into the water jacket thru the timing cover bolts 3.0 ( factory defect) front and rear main bearing seals leak more when their hot and pressurized than cold and flat also i never trusted those quick change places they never use a filter wrench to snug a filter,faster to use their hands.

 

[brokemechanic3000]

As I stated the coolant is clean and green and I am my own mechanic so I changed it myself. Went through and tightened all the bolts I could reach.
This was the first time I was that low on oil since I bought the truck.
btw there is only 145,000 miles on it.

A side note does anybody know if the throttle cable is adjustable. I couldn't find an adjuster and I think my cable needs tightening if possible, would hate to have to buy a new cable. It is just a little looser than I would like.

 

[McCormack]

Throttle cable mod link.

 

[buckshotmudder]

1 quart every 3000 miles is the threshold I consider "normal."

Like I said, What may seem not normal for others seems normal to me. My 21 year-old 3.0 has over 300k and a small leak.

 

[buckshotmudder]

As I stated the coolant is clean and green and I am my own mechanic so I changed it myself. Went through and tightened all the bolts I could reach.
This was the first time I was that low on oil since I bought the truck.
btw there is only 145,000 miles on it.

A side note does anybody know if the throttle cable is adjustable. I couldn't find an adjuster and I think my cable needs tightening if possible, would hate to have to buy a new cable. It is just a little looser than I would like.

Do the cable mod. Tightens it right up. I recall mine took two zip ties.