Vanishing Oil? Where you sneakin off too..

[01pathfinder7]

New to me 2001 pathfinder SE, Just been getting to know her and changed the oil less than 150km ago.

I used mobil 1 5w-30. Filled it up to the full line. Checked it for the first two days all looked well seemed to be right at the full where I left it.

Today I pulled the stick, and it was almost empty!!! On the L. I topped it off with my tail between my legs and drove home.

I look under this car everyday. NEVER has there been a puddle, or even a drop. There is absolutely no oil in my coolant which i checked and tested today. There is NO! smoke coming out of the muffler. There may be some black build up around the exhaust pipe but Im not sure whats normal.

There is a small brass femco looking tube on the bottom of the engine. When i was in my shop today I was changing my fuel filter and i reved the engine lightly to make sure I had to leaks. When i went to check there was a small little oil pile under this femco..but frankly im not sure if it was from my truck.

There are signs of minor oil weaping but never anything that can drip. Ugh...any ideas

[04pathse]

The oil coolers do tend to leak on these engines, but I would think with that much loss you would definitely see signs of it on the oil cooler and on the ground...

2001-qx4-oil-leak-need-help-identifying ... 79726.html

[atraudes]

Well, oil can disappear to three places. If you have a head gasket leak, then it could be mixing with the coolant, though the oil in the engine would look milky. The other possibilities are that it's getting burned up by the engine or leaking on the ground. The leaking is pretty easy to confirm or discount. Throw a large piece of cardboard underneath after driving a while and pull it out after an hour or so. If you still don't see anything, start the engine and rev it a bit and see if that produces anything. Also, crawl underneath and see if anything is really oily. If it is, clean it up with some brake cleaner and rags and see if it comes back.

As far as getting burned up, there's a number of things that can cause it, but the typical cause with these engines is it ingesting a power valve screw. You can check to see if this is the case by pulling off the upper intake plenum and inspecting the power valves in the lower section. Check out the howto in this thread to see how to do that:

threadlocker-on-power-valve-screws-pics-t304263.html

There are plenty of other things that can cause oil to get burned up, but what you describe is quite excessive. This thread is a worthwhile read, too, if you haven't already:

post6627485.html

I'd start by confirming that it's not leaking, and if that doesn't pan out, pull the upper intake plenum.

[rgk]

These cars burn a lot of oil. Unfortunately, you will not, I repeat, NOT see the oil coming out of the tailpipe as blue smoke. The soot in the tailpipe confirms this.

As atraudes said, it is most likely due to an ingested power valve screw. Mine ingested eight and still runs fine, though it burns about a liter every 1500 km. I believe the cross-hatched area on the dipstick is half a liter of oil.

If your power valve screws are fine, it could just be worn piston rings. But these cars are well-known to ingest these screws, and there's a lot of burners out there.

You may want to replace your PCV valve and switch to 10w-40, that helped me somewhat. Do you have a P0420 or P0430 engine code? Your cat will probably be under efficiency, as it is swallowing the burnt oil.

[01pathfinder7]

Well that sucks. I really have been praying this was a good car but after weeks of surfing the Web I have no idea why I or anyone would buy these factory lemon s*** boxes. I'm pretty upset. No lock tight sounds like their problem and now I'm out 2300. Thanks nissan

[rgk]

It is their fault, but before calling the scrap man, pull your intake plenum and check the screws. Does the car run and idle OK? If so, don't freak too hard just yet.

However, immediately also check your strut fender housings for rust, because that issue is a killer.

[01pathfinder7]

This car sounds and runs great sits at 900rpm idol without any signs of rpm flicker or any sounds. It really purs. Going for a test run now starting with full oil. Will update with loss per km

[01pathfinder7]

I could try thicker oil but winter here is cold. What's the highest you would recommend and high milage specific

[rgk]

You will know best based on your temps. I am doing 10-30 in winter and 10-40 in summer.

How is your strut tower looking?

[01pathfinder7]

Strut tower is all good. Lived it's life away from the sea in low humidity. Full tank of gas. Changing oil to 10w30 semi syn.... High milage. Little worried about the semi syn

[01pathfinder7]

Strut tower is all good. Lived it's life away from the sea in low humidity. Full tank of gas. Changing oil to 10w30 semi syn.... High milage. Little worried about the semi syn

[rgk]

Worried? Why?

[atraudes]

Just stumbled across this, sounds like some have had luck using conventional versus synthetic in cases like yours:

best-oil-for-a-120k-mile-engine-t487993.html

[01pathfinder7]

So it's test day 10w30 high mileage SAE? Is that synthetic? If not it's conventional oil. Honestly gas millage is through the roof almost 600 to a tank. Love my fuel filter change. After 300km I tried checking the oil but it's so clean it is hard to see. I added about 200ml, what I had left. Sat for a bit and looks to be just under full, I also realize how short the full to empty line is now. I didn't see the line and was judging more by the h itself. Driving home tonight will check in the morning.

[01pathfinder7]

PostThu Apr 08, 2010 12:44 pm

""Oh and my QX4 has 175,000km on it and I added synthetic to it when I bought it with 167,000km. I'm still at the full mark almost 6 months later. Maybe the 3.3 is better at keeping oil that the 3.5. Doesn't the 3.5 have that issue with syphoning oil through the PCV valve?""

This is ominous anyone else know more about that?

[atraudes]

My 3.5 doesn't have a noticeable drop between oil changes (~5-6,000 miles), fwiw. I use Mobil 1 5W-30 High Mileage, which is a full synthetic. My PCV valve is new-ish (replaced in the last year), and I know it never sucked in a power valve screw.

Dunno if the oil you're using is synthetic or not; it'll say on the bottle.

[01pathfinder7]

Did you replace your PCV yourself or shop. Sounds like a annoying job more than Anything

[atraudes]

I did, while I had the intake plenums off for something else. I've taken them off a few times now for various projects, so the procedure is a snap for me. The first time can be a bit daunting, especially as you track down whatever tools you're missing for the job. The power valve procedure gives you the steps on removing the plenums though I found the steps in the Chilton guide worked better for me. If you do it, be aware that some 01s had a screw-on PCV while others had a push-in. They're only 3 or 4 bucks each, so grabbing both and returning the other when you're done would be prudent.

[barnaclebob]

Borescopes can be had pretty cheap these days and make inspecting the power valve screws easy if you just snake it behind the throttle body.

FWIW my 01 LE still has the screws at 146k and doesn't lose any oil although I don't check it religiously.

[rgk]

High mileage oils are part synthetic. I have read that these engines are not equipped to take advantage of synthetic oil.

If you're worried about oil being siphoned through the PCV, you can install a catch can.

[01pathfinder7]

Really appreciate all the help. But! Update :

Changed to 10w30 high milage. New filter because I had a fram prior to reading a lot of post against haha. Drove 250km didn't burn/use/hide a drop in same driving conditions. very happy will keep an eye on it but all seems well concidering it was empty by this time last time.

The truck sat for two months before I bought it so hopefully it just needed some love.

I'd feel foolish not doing the PCV now but I may wait till after winter as I'd hate to mess with a "good thing" and my shop access is seasonal and will end unexpectedly. Thanks again I'm sure I'll be around to pick your brains

[rgk]

I hate to rain on your parade, but having gone through precisely every range of emotion in this thread, I can guarantee your vehicle will continue to burn oil. Be prepared and top off as necessary.

[01pathfinder7]

I don' t mind a little rain. 1400km now still not burning.

[rgk]

Well, that's good. Mine burns a quart roughly every 1500 km.

[barnaclebob]

I'd feel foolish not doing the PCV now but I may wait till after winter as I'd hate to mess with a "good thing" and my shop access is seasonal and will end unexpectedly. Thanks again I'm sure I'll be around to pick your brains

If a lot of oil is getting through the PCV wouldn't you be able to see a bunch of gunk and buildup downstream of the throttle body? When I cleaned my throttle body I remember seeing some gunk buildup on an inlent just downstream but it wasn't a lot so I didn't worry about it. Not sure if that's where the PCV vents to but it seemed to make sense.

Before you replace a working component maybe clean that area and see if you get a buildup quickly. If your oil consumption returns and that's where its going then I'd assume it would be noticeable but I'm no expert in this area...

[01pathfinder7]

So 1500 and the dips tick is down just above half. Less than 3/4 anyways. And I really find it smells of gas. The last owner had a Haynes manual and has a "running too rich" code circled. I have yet to have this code come since I owned it but it must have happened in the past. I run 87oct instead of 91 only because the last owner did as well. We live at 1700m, and he was around 1400m elevation. I read somewhere St these elevations are okay for 87. Anyways could the fuel being used cause any of this. I'm worried of the gas smell more than the burn now, oil still looks thick and clean like oil.

[atraudes]

A gas smell in the oil is not good. The gas will break down the oil and decrease its effectiveness. It's caused by too much gas being in the cylinder or it dripping in rather than being sprayed. What happens is the gas ends up "washing" the cylinder walls, doesn't get combusted properly, and drips down into the oil. The two causes i can think of off the top of my head are leaky or clogged injectors or the membrane on your fuel pressure regulator or fuel damper being damaged allowing gas to be sucked up through the vacuum line. All of these would cause a too rich condition, though it's not surprising that you're not currently getting a code. I had the same problem and never got a code about it.

I'd eliminate the fuel pressure regulator (FPR) and fuel damper first since they're super easy to check. Pull off the plastic engine cover and pull the vacuum lines off of each of them and smell them. If you smell gas (or it drips out), it's likely bad. If you want to be absolutely sure, pull the vacuum line off and run the engine for a few minutes. If it's truly bad, gas will start dripping out of the vacuum port.

In this picture, the FPR is the silver cylinder with the vacuum line coming out of the top. The fuel damper is right next to it and is goldish and has the vacuum line coming out of the side:



If you end up replacing either of them, I posted a howto on the subject. It's pretty easy.

[01pathfinder7]

I'll never get over the vast amount of information here. Thank you very much will check and update.

[01pathfinder7]

Doesn't seem to be my issue. Both hoses were dry and drip free and only the most faint smell of fuel but more smells like rubber.

[atraudes]

I forgot to mention...was the engine warm when you tried? If not, try checking after coming back from a drive.