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hi,

I changed the oil at 12,500 5w-20 mobil one and i just checked the oil dip stick, it drops to half between low and high mark at 16,200.

is this normal for mobil oil to burn some oil off and it show a bit tan ??

Its 5.4L 2004 F150

Am i parniod for nothing ??

Thanks!
YOMAN!

 

If you used the recommended amount of oil, the level will be at the mid point in the hash marks on the dipstick.

 

I've seen something similar with their 7500 mile blend -- I suspect evaporation of some lighter component.

 

The safe range is in-between the low and high hash marks. As long as your oil level is "in the range", you are OK.

I've noticed that Mobil products seem to bring the oil level to halfway between the marks on my dipstick on a fresh oil change. This is in contrast to Motorcraft or Castrol products which seem to bring it much closer to the "high" hash mark. Is this scientific? Heck no, but it is noticeable. Am I worried? Heck no...

 

Yes, exactly 6 quarts will put it half way between the marks if the old oil was fully drained. Some people and some techs like it up to the top line, or they want to sell you a little more. So they put 6-1/2 quarts in (sometimes more). This is easily done if you're filling from bulk as do most pros. So be sure that the fill volume is the same, and the old oil is all out.

 

One pint of oil consumption in 3,700 miles and you are worried?

Jim

 

Synthetics are known for NOT evaporating so that would not explain the lower reading.

If it possible that you have a small leak and that the syn which is usually thinner in my non scientific view, may leak a bit faster.

Could also be that the syn is clinging to parts better and not all of it is sitting in the pan. Or maybe the rever is happening, the dino oil clings to the stick better and shows higher.

Either way as long as you are in the hash marks you are fine. If you are burning a quart or less in say 5,000 miles or so, you are within the norms. Some manufacturers consider something like a quart every thousand normal, I think most of us here do not.

With only 16,000+ miles on the truck, you don't have enough repeat data to find a normal trend.

Good Luck,

Jim Henderson

 

There is a "volatility" to synthetic oils - that's how much will evaporate over time... the higher the temperature, the faster it boils off.

This is due to solvents used to modify the viscosity. I would imagine that certain production runs have a different amount of volatiles in them, so that the evaporation rate can change from batch to batch.

There is a graph on Amzoil's site (not that that's conclusive, of course) that shows the volatility of all different brands of synthetics. I don't remember the particulars anymore, but using the value for Mobil 1, I came up with 1/2 to 1 qt evaporating off over 3-5K miles. That sounds about right, given what I've read on this site.

 

I should have been more specific. The dinos were known to evaporate at a faster rate than syn that is what I meant by syn being known not to evaporate. I should have said evaporate at a much lower rate than dino. Least that's the way it was before they got into the heavy hydro cracking dino. Perhaps now the good dinos are less evaporative as they become more syn like. The syns were passing the more current extended evaporative tests long ago(before the tests were required), the good dinos appear to only have gotten there in the last few years from what I recall reading.

From the Mobil1 website... Historically, conventional oils lack the performance of synthetic oils in the areas of low-temperature performance and high-temperature oxidation stability. Conventional motor oil is made up of an inconsistent mixture of long and short chains of carbon and hydrogen atoms. In the extreme heat of an engine, short-chain molecules can evaporate, and unstable molecules can oxidize and break down. Conventional oils also contain much greater amounts of impurities, such as sulfur, reactive and unstable hydrocarbons, and other undesirable contaminants that cannot be completely removed by conventional refining of crude oil.

I have seen other sites(not just mfg's) that specifically mention the evaporation issue with dinos versus syns. Problem is I don't file them away for easy access, more of a jumble of papers.

Jim Henderson