A couple of questions. I'm currently running the Castrol synthetic on my 01 F150. It has a 4.6L engine with 140K miles. I don't abuse it and the miles are split about 50/50 between highway and local. About how many miles can I get between oil changes?

Also, is there an advantage to synthetic over conventional? When gas spiked to over $4/gallon the price on a 5 quart container of synthetic went from $19 to $26. Since gas has come back down to less than 2 bucks I haven't seen the corresponding drop in motor oil. Still running $26.

 

Well, Castrol Syntec isn't a real synthetic, though it is a very good oil. I would run it between 5,000 - 7,500 miles, beyond that, you be the judge. I don't think its good for much longer than that. I run Royal Purple myself, and get between 15,000 - 20,000 on an oil change.

A lot of people swear by Mobil1, and while I don't like it mostly because it is an Exxon-Mobil product (my issues with them are political, when are we gonna see the Alaskan oil they promised was for the American people?) Amsoil makes an excellent synthetic oil as does Redline. If you stick with one of those four, you can get your moneys worth because these oils all use high quality base stocks and can run well beyond 10,000 miles (Amsoil claims up to 25,000 miles, and yes they have the documentation to prove it.) Now you have to get oil filters that can handle that type of duration. Mobil1 offers a line of extended life filters that have up to double the filtering capacity or roughly 15,000+ miles per filter.

The advantages of synthetics is reduced wear (especially at startup), improved thermal and chemical shear strength (the oil can handle more of both before it begins to deteriorate), improved detergent strength (the oil itself is all the detergent it needs, while regular oil has to have detergents added), better viscosity characteristics (the oil acts like a thick oil in terms of surface tension strength and viscosity, but flows like a light oil), and it lasts much much longer, allowing extended service intervals.

 

To me if you can't run the synthetic long enough to make it cost the same as changing the conventional oil every 4K-5K miles it isn't worth it. Every synthetic I look at you need to run around 10K or more to break even and personally I will not let an oil stay in that long no matter how good it claims to be. The engine wear issue is moot IMO as the engine should last 10''s of thousands of miles with conventional so what is synthetic going to add to that? Not enough IMO.

 

Maybe I got the name wrong but I thought I was running a full synthetic. I do use the Mobil 1 filter (and I have used the Mobil 1 oil). I was thinking 7500-10,000 as an interval. Much less and it seems hardly worth it given the $13 filter and $26 for the oil. I'm north of $40 having to change it myself so that prompted my question. I take care of my stuff and will drive this thing til the wheels fall off. I just don't want to do anything to bring that on prematurely.

 

i use full synthetic in my truck, i usually go between 5-6000 miles before change, any longer and i start to worry about it, it cost me about $40 to do it myself. im like you i want this truck to last a long long time

 

i use a good quality dyno oil and change it every 5000 miles. that way you get any crud, dirt, water, etc out that contaminates the oil. thats basically what Galaxy said. It is also a timed thing. If your running cross country and put 10,000 miles on a truck in 3 months, then longer intervals will work. If you drive short distances and put 10,000 miles a year on it, i would not leave any oil in there that long. Change more often and use a good dyno oil and you will come out ahead in the long run, if your driving under
15k a year

 

Synthetic oil gets dirty at the same rate as dino. Unless you are doing something really extreme with your truck, I'd use Motorcraft 5w20 and be done with it. It's semi-syn anyway.

Extreme being very cold starts, very hot operation, high RPM for a long time, etc.

I use MC 5w20 with a MC filter and go 5K between changes.

Mike

 

i used to use quaker state peek performance and now use motorcraft, wit a mc or purolator pure one filter(depends if advance has the mc one) wit 2qt of lucas additive.

 

I use synthetic for the winter purely for the cold start properties, and I run it for approximately 5 months regardless of miles until the weather warms up. Otherwise, it is off to Walmart to find the cheapest price on 5W20 whether it be syn or dino....doesn't matter.

 

I have used synthetics before. Used to use Amsoil on my cars, I would change it every 10,000 km, and change my motorcraft filter every 5000 and just top up the oil. At 10000 km the oil looked great still.

I use Castrol GTX 5w-20 in my truck because it seems to work well and is cheap, I use a motorcraft filter and change it every 5K. This has lasted me 70k + so far since I got my truck putting it at 185K. If I had it from new I would have stuck with the Amsoil.

 

Castrol sells both full synthetic & a synthetic blend under the "Castrol Syntec" name. Pretty sure Castrol considers their full synthetic "a real synthetic".

Castrol USA - Castrol SYNTEC

Incidently, mineral oil is predominantly from accumulations of ancient plant material. Petroleum has almost nothing to do w/dinosaurs, the myth that it does is the source of the slang "dino oil". When stever(ill) posted "dyno oil" we entered uncharted territory.

 

Hey CW: since you always enjoy gloating in your correctness (even though you seem to be correct about half the time), "mineral oil" is a product of distilling petroleum; it is not a generic name for the stuff that comes out of the ground. George

 

Hey YG: "since you always enjoy gloating in your" choice of Off Topic nit picking & edicts as judge/jury (even though you seem to be incorrect at least half the time), "mineral oil" IS a common generic term for conventional motor oil. The term "mineral oil" is used very often in articles promoting synthetic oil to differentiate it from traditional oil. In geology it also refers generally to oil that comes from deep underground. In any event, that IS how I intended it to be understood.

I presume you refer to the clear household "product" often sold in small bottles, near the rubbing alcohol, known as 'Mineral Oil'? That "product" has no application in this Topic on motor oil for FORD & was NOT what I referred to.

If you have issues w/Castrol Syntec's website please feel free to take it up w/them.

 

if you consitently drive the same, sending an oil sample in would tell you if you can go further on your oil changes. Any big rig shop can give you the name of reputable lab., and usually have pre labled sample bottles same with farm tractor dealers. I am going 10,000 on valvoline full synthetic 5-30 and it is dusty muddy hard pulling weight packing coonditions here on the farm Point is for 20.00 you have your answer no guessing.

 

I wouldn't be concerned about which type of oil you use; as long as it is a well known brand.

Furthermore, stay consistent. Whatever oil you're using, stick with it. Don't change just because someone on here says to.

Change your oil @ either 3k or 5k.