Maybe someone could help me with this one...
I run have always Mobil 5000 5W30 in my 2000 F150 5.4L. I recently went to buy a case of it & they were out of it so they gave me the Mobil 7500 5W30 which is a synthetic blend at the same price.
My question is after running normal 5W30 can I use a synthetic blend & then go back to the normal oil after the case of Mobil 7500 is used?
I don't want to keep having to buy synthetic blend oil because it is way too expensive. A buddy of nime told me that once I start using a synthetic blended oil I can't go back to conventional oil - TRUE OR FALSE?

Any advice is appreciated....

Thanks

Brian

 

Ive never heard of any problems switching from synthetics to conventional oil.

Theorectically you can use a different oil every time you change the oil, it wont make much difference.

The main "problem" is on engines that have been using conventional oil for a long period of time tend to get some build up around the seals. When you go to synthetic oil, its pretty good about cleaning out the old crud, and this can cause leaks if your seals arent good.

I dont see why you cant go back to conventional.

 

You can chnage to a blend, a synthetic, and back to a dino if you like. They are in basics the same hydrocarbons. Dispite advertizing hype, no synthetic will add one mile to the life of your engine under normal conditions. They do not possess any more lubricity; they are not slicker, they do not reduce friction over another type of basestock. The advantages of a synthetic is its thermal properties. The blends will show the fewest wear metals in analysis. It's getting harder to find a bad oil these days. The Mobil 7500 will serve you well and when it is gone, buy your favorite brand.

 

Have you ever disassembled an engine running synthetic oil and compared the main bearings and crank to an engine running Dino oil??

"The advantage of a synthetic is it's thermal properties"....that's not all...also they have better additive packages allowing extended drain intervals coupled with the proper filtering media, off course!

I can tell you will not be swayed to the benifits of synthetics and I will not discount my experience using synthetics. So lets agree to disagree


To answer the original question....yes you can switch back to whatever oil you choose.

 

oil lubricates by bonding to the surface of the steel.. so yes changing oil can effect the lubrication qualities of the oil so keeping same oil type is crucial. but going from full synthetic to regular oil will show some issues since synthetic tends to bond to the internal components well. so its usually best to keep same brand and type of oil throughout ur engines diet. if u want an example take regular 5w30 and try to get it to mix with full synthetic 5w30... u will see why keeping same oil is a good idea in your engine

 

"oil lubricates by bonding to the surface of the steel"

NO! NO! NO! Where do you get this stuff??

Synthetics and Dinos mix NO problem....read the labels!

 

"oil lubricates by bonding to the surface of steel", somebody's been watching to many duralube commercials

 

I know a couple things and I will pass them on.
1- In my 88 F-150 it always had dino with no leaks, I put a blend in it and it cleaned out my engine and made leaks form old gaskets. Good-Bad? Who knows. I know it didn't hurt to back to the dino when I was done. The leaks looked worse than they were. Big puddles but never had to add.
2- I have a 90 FSB with a 5.0 it has had full synthetic in it from the first oil change. I have 188,000 miles on it and it still pulled my camper up to the white mtns in AZ this year.
3- I own a 18 wheeler type truck that I put 12,040 miles a month on. A lot of guys are running Synthetic. I use it in my rear ends and trans. If you mix them very bad things happen. It pretty much turns to glue in there and then you get a lot of smoke and them you get a $900 tow bill.
In the end if your truck will hold the blend I would use it..It's not that much more than Dino oil. Just my thoughts from what I know not what I see on TV. Hey I am thinking of getting a Tornado for my new truck. Can't wait to see the savings there. NOT!

 

Synthetic oils have no more detergent than a dino oil....they don't cause leaks.

So if I use a dino oil that allows sludge to form around gaskets preventing leaks that's a good thing....if one went for this analogy one would conclude...."Dino oils suck"...they gum up the engine

"If you mix them very bad things happen. It pretty much turns to glue"

Ah, NO.

 

if it doesnt bond to the surface of the steel to some aspect it will not prevent friction.. its like why wear a condom if it wont stay on the "moving part" long enough to function as its suppose to.

 

Oil does not bond, oil does create a film or a boundry layer around the metal.

 

Oil does not bond to anything. Bonding is actual physical adhesion, like glue. As when a engine locks up from a lack of oil the bearings bond to the crankshaft. Engines have internal clearances for a reason. Oil does cling to moving parts. Your engine bearings actually have a thin film of oil between them and the crank or cam or other moving parts when the engine is running. Thats why startup is so hard on engines. The only oil on the bearings on startup,for a second or two is clinging residual oil from the last drive cycle. So back to you original question just use a quality brand oil like Motorcraft 5w20 and you will be fine.

 

Faster, I do like the condom example. Its not a bonding issue though. Sounds like a clearance issue between the the condom and the crankshaft. Like the crankshaft was ground a little too small?

 

There is another problem with your condom example

If the condom BONDED to your "moving parts" then...you would permanently have a condom attached to your "moving parts" and, well, that might cause some, er, issues