Second Generation Nissan Xterra Forums banner

1 - 8 of 8 Posts

·
on line
Joined
·
257 Posts
Discussion Starter #1 (Edited)
I change my oil regularly and until now, really only check the oil once a month. Checked it last month and noticed I was a quart low. Added a quart and thought maybe I got lazy and skipped a quart on the last change. I am concerned because I haven't used any oil to this point between oil changes.
Here's what I know: It has 138,000 miles on it. I don't get any blue smoke on start up, long runs of compression breaking, or steady amounts of high throttle. Plugs aren't showing any sign of oil fowling, intake is clean and pcv valve is working correctly (or at least appears to be), engine coolant is clean and no drops of oil in the driveway or garage. Where is the oil going!!!!

Thoughts?

Follow up
It appears that I have may have a small usage but seems to be reasonable. I just topped it off again with a part about half a quart in two months time (141,000)
 

·
Registered
Joined
·
248 Posts
You're on the right track. In your situation a compression test would be the very first thing i do as i check plugs.

Have you pulled the PCV to test it? Without a catch can or pulling and filtering in some way to see what it is doing i don't know how it can "appear" to be working properly. Testing is super simple and replacing is cheap. Specially considering your mileage and PCV being something that people never replace regularly
 

·
Registered
Joined
·
575 Posts
How many miles per quart? Not rare for engine to gradually burn more oil and may go many thousand more miles before burning enough to cause noticeable blue smoke. Might try changing to different oil and using 10w-30.
 

·
Registered
Joined
·
1,049 Posts
You're on the right track. In your situation a compression test would be the very first thing i do as i check plugs.
^^ THIS

140k could simply mean your cylinders are so worn that you're now burning oil. You wouldn't necessarily see smoke at start up, that's more of a symptom of valve guide wear.

If it's the cylinders, weigh the cost of oil versus a rebuild... Oil is usually cheaper. :drink:
 

·
Registered
Joined
·
1 Posts
I have a 07 X with 103k. A few months back the truck was burning oil like crazy but I couldn't see any physical oil leaking. I would have to put a few quarts of oil every week. Fast forward a bit and oil started spewing out the bottom and was all over the exhaust. The truck was smoking out the exhaust upon start up and while driving. I had the PCV Valve changed, valve covers, and valve gaskets. This seemed to fix the problem until today. I have had the truck back for about 3 weeks and the oil was almost gone and I had to dump 4 quarts into it. There are no visual signs of oil leaking anywhere and I am at a lost here. Any ideas???? By the way, new member so I am sorry if I am not doing this correctly. Thanks
 

·
Registered
Joined
·
1,082 Posts
I have a 07 X with 103k. A few months back the truck was burning oil like crazy but I couldn't see any physical oil leaking. I would have to put a few quarts of oil every week. Fast forward a bit and oil started spewing out the bottom and was all over the exhaust. The truck was smoking out the exhaust upon start up and while driving. I had the PCV Valve changed, valve covers, and valve gaskets. This seemed to fix the problem until today. I have had the truck back for about 3 weeks and the oil was almost gone and I had to dump 4 quarts into it. There are no visual signs of oil leaking anywhere and I am at a lost here. Any ideas???? By the way, new member so I am sorry if I am not doing this correctly. Thanks
You could always get something like this.


https://www.amazon.com/Tracer-Products-TP34000601-Fluorescent-Detection/dp/B000JFHNTM

The funny thing about leaks is they can be hard to find since you drive and it can blow everywhere. The PCV would be my first look and if it worked for a short time I would maybe replace it again. Its job is to release the pressure in the crank and if it is not working crank pressure builds up and it pushes oil past the rings. Of coarse the leak detection dye will only show leaking oil not burned but it is a start. 1 quart per 1k miles is normal for a newer vehicle some have even higher listed.
 

·
Registered
Joined
·
1,724 Posts
Probably getting a lot of blow-by, from worn piston rings as mentioned. They do have some 'engine restore' and similar products that may help a little, although if this is the case of rings then you may be on borrowed time. Normally if they're shot, you'd get some smoke under acceleration, so they probably aren't *that* bad...Another area for leak potential are the valve seals, but typically you would see smoke on deceleration if that were the case, especially going down long hills letting off the gas.
 

·
Registered
Joined
·
509 Posts
^^ THIS

140k could simply mean your cylinders are so worn that you're now burning oil. You wouldn't necessarily see smoke at start up, that's more of a symptom of valve guide wear.

If it's the cylinders, weigh the cost of oil versus a rebuild... Oil is usually cheaper. :drink:
Cylinders don't wear out, it's the rings and the valve seals/guides that will fail. 140k is very low mileage for rings and guides to start wearing out, ESPECIALLY on an Xterra. A cheap Hyundai, maybe. If there's no smoke and the compression is still in spec, the rings and valve seals/guides are likely in good shape.


My question to you is when you change your oil and filter, do you simply add 5 quarts? When I change oil and the filter I have to add 5-1/2 quarts to get it to the full line on the dip stick. If you're only adding 5 qts, then you're already a 1/2 quart low.

All that being said EVERY vehicle I've ever had (gotta be over 15 vehicles) goes through oil without smoking or having any leaks. A quart low after 5,000 miles wouldn't scare me too bad if you're not seeing any smoke. More than a quart in 5k miles might be worrysome, but if the motor is running fine and you have no loss in compression or noticeable power then I wouldn't worry too much.

But DEFINITELY keep a closer eye on the oil level - low oil levels are way more concerning than a loss of a quart over 5k miles.

Also, different types of oil can lead to oil loss. I've noticed that when I was running Valvoline Max Life, I would always be a quart low when I changed it. Now that I'm running Mobile1, I'm usually only 1/2 low or less.
 
1 - 8 of 8 Posts
Top