Oil level goes down just a small amount

[ScubaDive]

I have just always kept an eye on the oil level, out of habit. I have noticed for the past few months that I'm adding a little 250ml - 500ml and that just a rough guess to bring it back up to the full mark, over a period of 2month, again rough guess.
So I drive about 50km one way to work on 12hour shifts and I can drive about 200km and check the oil level on level ground and don't really notice any drop. I can check it again after 2000km and notice the drop, not by any means a significant drop but still. I don't see anything left on the driveway nor do I see any evidence of oil under the hood, no evidence of it out the tail pipe or in the rad, and the truck has no fault codes. So where is going and what can do about it?
I keep up with my oil changes and put in full synthetic.


2008 Ranger Sport
3.0L V6
Auto
~180,000km

 

[adsm08]

Well I don't know that I'd waste money for full synthetic on a 3.0, and if and engine is switched from conventional or a blend to full synth after so many miles it will use oil.

Anyway, the range you gave for use is actually pretty wide. Allowed consumption is 1 qt per 5000 miles. The numbers you gave work out to be between 1 and 2 quarts in 5000 miles. That's a big range.

I would change the PCV and see if it makes a difference. It's a cheap part that could make the difference, and nearing it's service interval by the mileage you gave.

 

[ScubaDive]

Thanks for reply ADSM08.
I wasn't aware that by switching oils to a full synth is a bad thing, I figured I was doing a good thing. is there a reason why this happens when one switches oils ?
If I went back to a conventional would that help?

I will change out the PCV and see what happens.

 

[pjtoledo]

switching to a full synthetic is not a bad thing for the engine, however,,,
over the last 20 years and with several engines I've noticed that full synthetic is always used up faster than conventional oils in hi mileage engines.

on a side note, the last oil change to my 2005 2.3 I used that new refined-from-natural-gas oil in a 5-20 and my consumption almost doubled. probably doesn't help that 'ol Junior has 296,850 miles on it and as of that last oil change the daily driving dropped from 100 mi/day to 15 mi/day in short trips.

to answer where the oil is going, out the tailpipe. (how else can the muffler bushings get lubed???) its burned in the combustion process and comes out clean, sorta.

Perry

 

[ScubaDive]

over the last 20 years and with several engines I've noticed that full synthetic is always used up faster than conventional oils in hi mileage engines.

to answer where the oil is going, out the tailpipe. (how else can the muffler bushings get lubed???) its burned in the combustion process and comes out clean, sorta.
Perry

Why?
I really don't understand, So there is not necessarily a problem. But I do realize that oil does get consumed by the engine to a small degree but why would switching to a synthetic (better lubrication) make any difference in consumption??
Would I see a difference switching back to a conventional?

 

[adsm08]

As to the why, I don't have a good answer. I suspect it has to do with the way the engine wears and the metals get used to certain things. After so many miles the finer molecules of the full synthetic are allowed past the rings and the valve seals where the bulkier, less evenly sized blend or conventional will not fit. Similar to how an engine started on ether consistently will eventually become dependent and won't be able to start on its own anymore. I have read of mixed results switching back.

I would not switch to a conventional, as that isn't the specified oil either. I would use a "High mileage" semi-synthetic 5-20. The high mileage blends have additives that are specifically designed to help resist combustion, so they shouldn't burn off as easily.

As I said in my original post I consider the use of a full synthetic in a stock 3.0 to be a waste of money. For most engines full synthetic oils cost disproportionately more than the benefits available from using them. The only place they are really needed is in high-performance applications where fluid shear is an issue. It's something that is basically only needed if the manufacturer specifies it.

The difference between conventional, semi, and full synth is largely in how refined the product is, and the quality of the detergents used. The various "grades" are subjected to different levels of filtration at the molecular level to produce a more uniform molecule size as the grade (reads "price") increases. This helps reduce fluid shear under stress, which is a good thing, because shear will eventually break the oil down and it won't insulate the metal parts from each other anymore. This is where the idea that full synthetic lubricates better comes from. Its not completely false, but in the case of the 3.0 you just aren't making enough power to do that kind of damage to your oil.

The other factor is the amount and quality of the detergents added. Conventional oil has the least, obviously, and gets dirty quicker. Full synth has the most and will clean better longer, but for cleaning it still won't hold a candle to diesel oil, which is what I use when I can find it in the right viscosity. 5-30 diesel is hard to come by though. Detergent is important because most auto chem companies estimate that the oil filter really only works for the first 15-20 hours of operation, and after that it is up to the oil to keep things clean and the filter is just there to keep out large pieces of debris.

These two factors are what dictates oil change intervals more than anything. Run time, length of trips, engine temp, emissions controls, engine wear, and fuel quality all factor in as well, but breakdown from fluid shear and detergent quality/quantity are the two biggest factors. This is why synthetic oils usually have a longer OCI than the others. They have better stuff, and thus a better shelf life in the engine.


I personally just use the cheapest stuff I can buy, because I change my oil every 6 months regardless of miles driven. That's about the shelf life of most oils once the bottle is opened. Since I work about 3 miles from home and don't do much driving but to go to work and home again it takes me 6 months to rack up 500 miles. Especially now that I have my BII back on the road and am splitting my miles between two vehicles again.

 

[ScubaDive]

Wow thank you so much for that explanation you rock.
that clear things up so much.

So I really should be switching to a high mileage blend.
I guess I should be switching the wife Pontiac G5 back and use high mileage in that as well.
Do I have to do something special to switch into a high mileage. I have read that to switch out of a synthetic you should flush the old out and do an oil change after around 500km to make sure its all out.

The things one can learn.


again thanks

 

[adsm08]

I wouldn't worry about that. Just run it until your next oil change and then grab something in a high mileage. I think all of the oil makers recommend those after 75,000 miles, so about 125K km.

If you use a blend then it should mix in with any left over synthetic just fine.


FWIW I'd still change that PCV too.

 

[Rearanger]

I wasn't aware that by switching oils to a full synth is a bad thing

Neither was I. I've used full syn since new and loose none between 6k oil changes. Is this one of those; "Things my father told me." myths?

I also have done several used oil analysis with great results.

 

[adsm08]

While I admit to having zero first hand experience with this phenomenon it is a well documented thing.

There are many people just on this forum that have posted about switching vehicles with 75K miles or more that don't burn a drop to full synthetic because it was on sale or something and suddenly they are burning a quart every thousand miles.

 

[pjtoledo]

I'll agree that diesel oil is better, with a HUGE compression ratio compared to gas the bearings take a heck of a beating.
back in the day I had an 82 VW diesel, put 283,xxx miles on it, obviously diesel oil. it had a 23.5 to 1 compression ratio.
my 'ol 87 Taurus wagon made it to 163,xxx before rust took it. not much if any diesel in it. always synthetic.
92 Taurus SHO,(read 220 hp Yamaha v6) that regularly saw 7000 rpms started on synthetic, then used 15-40 diesel from about 150,xxx to 175,xxx. it ran quieter and smoother on the diesel stuff. usage went down too.
95 Taurus SHO, 105,000. was always synthetic.
current 2000 Ranger 3.0, now 108,xxx and has always had synthetic 5-30.
current 2005 2.3, 297,xxx and has always had 5-20 synthetic. consumption is now a bit of an issue.

basically any "good" oil now days is an excellent oil. the synthetic tends to run cleaner and gets consumed more on hi mileage engines.

all oils are fully compatable, except for that $1000 per quart crap they put in Ferarris.


Perry

 

[Rearanger]

As I said in my original post I consider the use of a full synthetic in a stock 3.0 to be a waste of money.

Depends. If you buy a new vehicle every 2-3-5 years then yes. If you do the 3k OCI then yes.

I think better filtration is more important than the oil. My Ranger is the first vehicle where synthetic has been used since new. It's produced great UOA results and with long OCIs I'm not paying extra for oil.

I am paying extra for filtration though with an Amsoil dual filter setup. I actually have analysis results that show my insolubles down to trace levels.

Very expensive Redline and Amsoil synthetic showed no advantage to Mobil1 from Walmart. I do like Redline gear oils over anything else.

 

[ScubaDive]

Ok really good info... wow

So I shouldn't have an issue just switching to high mileage on my next oil change, which I hope its better weather when that happens, in the driveway on snow sucks! What needs to happen if I switch to a diesel oil? and does that require a special filter?? I do what I can to pro-long the life, I don't like buy vehicles.

 

[Rearanger]

What needs to happen if I switch to a diesel oil?

I would do some research on the diesel oil thing. I've never investigated or tried it, but the weight seems like a flag, especially in cold start-up.

You need good flow in cold weather to reduce the time the engine sees little oil lubrication. Don't risk faster engine wear for less consumption - in the end you'll get the worst of both.

 

[pjtoledo]

I would do some research on the diesel oil thing. I've never investigated or tried it, but the weight seems like a flag, especially in cold start-up.

You need good flow in cold weather to reduce the time the engine sees little oil lubrication. Don't risk faster engine wear for less consumption - in the end you'll get the worst of both.

definitely.
standard diesel oil is 15-40. to say the least, it's kinda thick below 30 degrees.
I'm not sure what other weights are available, haven't looked lately.
I always used the specified filter for the engine, never had any problems.