Oil: I'm Not Convinced It Ever Needs To Be Changed

[crazyal]

Good read from Ford 6.0, 6.4 and 7.3 Oil Bypass Systems and Billet Aluminum Filter Caps


So it reads like if I put a bypass system into my F350 I could get by changing oil 15K or more.

It's not that simple. There's three properties that need to be checked, contaminates (which they are talking about can be filtered out), additives used to modify the way the oil acts when cold (or in the case of synthetic warm), and detergents used to keep the engine clean. If you filter the oil better then the need for detergents to keep the engine clean drops. However unless your engine is always at operating temperature, say a semi that the engine is always running or a locomotive that also rarely shut off you will need those additives.

The vast amount of damage done to an engine is when the oil is not at it's operating temperature. Usually around 200F. In the old days we had just plain old 30 weight oil (along with other weights). But what happens is 30 weight oil at room temperature did a very poor job lubricating engines. So along came 5w30 (and others) oil. Oil that would act like 5w weight when cold but once at operating temp it was 30 weight. To make it act like 5 weight additives were put into the oil. Over time these additives break down and the oil will become plain old 30 weight oil. Older engines were designed with looser tolerances to work with straight 30 weight oil while modern engines are not designed to run on straight 30 weight oil.

Synthetic acts differently. Conventional 5w30 oil is 30 weight oil with additives in it to act like 5 weight when at room temp. Synthetics are 5 weight oil with additives to act like 30 weight when at operating temps. So when the additives break down it becomes straight 5 weight. Since most wear happens when cold having too thin of oil at operating temps is not as much of a problem. That's why it can go longer between changes.

 

[jomar215]

So, is the bypass oil filtration system only utilized in a diesel engine? Perhaps I should note that I am currently 6,700 some-odd miles on mu current engine oil - which gives you my view on engine oil changes. I figured I'd change it after 7,000 some time.

 

[Willl]

The only thing that saved me was the driver said,"I think the car is driving funny." The oil had virtually no lubricating properties left.

What ?

 

[megaboz]

Synthetic acts differently. Conventional 5w30 oil is 30 weight oil with additives in it to act like 5 weight when at room temp. Synthetics are 5 weight oil with additives to act like 30 weight when at operating temps. So when the additives break down it becomes straight 5 weight. Since most wear happens when cold having too thin of oil at operating temps is not as much of a problem. That's why it can go longer between changes.

OK. I have heard a lot of weird talk about engine oil before, but this one is a good one. So what does a straight 30 weight synthetic emulate?

 

[Deere Dude]

This thread kind of reassures me to always buy new, unless I know the owner. I had an acquaintance who bragged about hardly ever changing his oil in his car and that he never greased the front end joints (Back when cars had greaseable joints) and that the car had 130,000 miles on it. The body looked fine and nothing was breaking down, so he figured he must be doing something right. It would be my luck to buy one of those cars or tractors that look good on the outside but ready to fall apart on the inside.

 

[CBW1999]

OK, let's see. 14 Kubotas and how many got past 50 hours. YES, BX1500 3 years:thumbsup: B7800 3 years :thumbsup: (When I owned them the 0% was for 36 months, they were paid off).:cool2: BX2200, L3240, BX2350, BX2660, B3200, Gas Kubota Mower, B2320 NOs ..... Still have F2680 4 YEARS OVER 100 HOURS(PAID OFF):thumbsup: F3080 almost 3 years OVER 50 HOURS(still own):thumbsup:, RTV1140 somewhat over 2 years OVER 50 HOURS(still own):thumbsup:, BX25 around 3 years and gone AND OVER 100 HOURS:thumbsup: and B2620 1.6 hours and still own. Did 50 hour service per owners manual on those I owned for over 50 hours. Early ones included HST fluid at 50 hours but past 5 years owners manual has only oil and all filters at 50 hours WHICH i FOLLOW..

........he who lives near Barlows- trades often.

Slight shift in the conversation- any difference in trans/hydraulic fluid? does "it" ever need to be changed? You mention earlier owners manuals having it part of the 50 hour service but not currently. Although not part of internal combustion, it is still subjected to high heat. Interestingly enough, the "hydro" transmission in my toro 217-d, uses 10w30 not hydraulic fluid. This is where I get utterly confused........

Same unit, the gear box for the mower deck uses 30w, not gear oil.

 

[megaboz]

I change my fluids usually either at recommended interval or a little longer if I have an analsys done and they report all is well.

In a clutchless gear box, motor oil doesn't surprise me.

 

[newbury]

<snip>
Synthetic acts differently. Conventional 5w30 oil is 30 weight oil with additives in it to act like 5 weight when at room temp. Synthetics are 5 weight oil with additives to act like 30 weight when at operating temps. So when the additives break down it becomes straight 5 weight. Since most wear happens when cold having too thin of oil at operating temps is not as much of a problem. That's why it can go longer between changes.

I've been reading BTOG and I think you have the synthetics and mineral oil characteristics reversed.

Let痴 look at the make up of synthetic based oils. A 10W-30 synthetic oil is based on a 30 grade oil. This is unlike the counterpart mineral oil based on a 10 grade oil. There is no VI improver needed. The oil is already correct for the normal operating temperature of 212ｰF. It has a thickness of 10 while you drive to work. It will never thin yet has the same long term problem as the mineral based oil.

http://www.bobistheoilguy.com/motor-oil-103/

and

To recap, synthetic oils have similar characteristics as mineral oils at operating temperatures. The synthetic oil will however be less honey like at startup even though it has the same API / SAE rating. Yet the synthetic 10W-30 grade oil is based on a heavier 30 grade oil while the mineral based 10W-30 oil is based on a thinner 10 grade oil. They are both similar at operating temperatures yet the 30 grade based synthetic is actually less thick at startup and much less honey like at low temperatures. This is the opposite of what common sense dictates.

This is worth repeating: The synthetic 10W-30 grade oil is based on a heavier 30 grade oil while the mineral based 10W-30 oil is based on a thinner 10 grade oil. They are both similar at operating temperatures yet the 30 grade based synthetic is actually less thick at startup and much less honey like at low temperatures. This is the opposite of what common sense dictates.

My TDI runs a synthetic and the oil change interval is 10,000 miles. Per VW. My F350 runs either with a mfg recommended interval of 5,000, but it looks like I could run mineral oil 8,000 miles and I'm waiting to find out my expectancy on synthetic.

 

[newbury]

........he who lives near Barlows- trades often.

Slight shift in the conversation- any difference in trans/hydraulic fluid? does "it" ever need to be changed? You mention earlier owners manuals having it part of the 50 hour service but not currently. Although not part of internal combustion, it is still subjected to high heat. Interestingly enough, the "hydro" transmission in my toro 217-d, uses 10w30 not hydraulic fluid. This is where I get utterly confused........

Same unit, the gear box for the mower deck uses 30w, not gear oil.

It greatly depends on the vehicle. My '88 Ford E350, van, leaks under power at an appropriate rate that I replace the entire fluids about every 30K to 40K, about 10 to 12 quarts. Fixing it would cost about $1,500 to have someone do it. That's a lot of quarts.

The Sato 360 that my cousin-in-law lent me went through about 3 gallons of Tractor hydro fluid this spring and early summer. I used it for about 30 hours max, he used it more.

 

[greasemonkeyok]

What ?

Sorry it wasn't clear, so I edited post #59 to explicitly say what was previously only inferred. Bottom line, I was just lucky and caught it just in time to save the engine.