I have a 98 F 150 4.2 V6 with 307,xxx miles. Would it hurt to chance to synthetic oil? or Should I stick to my regular oil of 10 W 30

 

I would not think it would hurt but why change to syn when reg oil got it to 307k?

 

If your of a mind to try a synthetic for it's cold flow properties, to ease starting in your cold country location, maybe consider trying a synthetic thats made by the same company you've been using, so the seals, gaskets, deposits, ect, aren't upset with a different ad pack chemistry.

As has been said, if a regular dino oil diet got this puppy to 300K+ miles, why change????
Would be interesting to know which brand & recipe you've been using to get it this far.

Todays API SN/GF-5 motor oils are mostly Group 2+/3 blends, so they're plenty good for most things we'd likely do with a truck.

More thoughts for pondering.

 

Personally I would stick to regular oil. It is clear it has worked quite well with 300K+. All your going to gain is possible oil usage & leaks, not to mention more cost to change oil. The only thing I run Synthetic in is my SV650S. It revs to 11,000 RPM. But all my 4 cars & trucks run regular oil.
Craig

 

I run Rotella Synthetic in my '08 F350 6.4 diesel. So far so good.

 

I run Rotella T6 5W-40 in my 86 5.0. Decreased oil consumption completely and didn't cause any leaks. I switched over to it about 3 or 4 years ago.

You can swap from conventional to synthetic. In my case, maybe I didn't get any leaks because Rotella T6 is Group III or Group III+ mainly, and not a "true synthetic". But, very few synthetics are true full synthetic, anyways.

BUT, conventional oils are amazing today. 5W-30's don't shear down like they used to and they can go 5k-6k miles fairly easy. I just wanted to use a good priced HDEO for the extra zinc since I have a flat tappet cam. Just wanted to be on the safe side.

So, in your case, it depends on your budget and what you are looking for in an oil. If you want better cold flow properties then a synthetic is definitely the way to go. If you want to extend your oil change intervals, it's another good reason. What brand oil have you been using? I mean, to hit 307k miles and have a good engine, you have already been doing something right. And like papaw said, it wouldn't be a bad idea to go to a synthetic with the same additive pack just in case. But, also, I feel that if I changed my truck from Kendall oil after 21 years to Rotella T6 and my oil consumption went to none and it didn't create any leaks, it may not be much to worry about.

 

You started using DIESEL oil in your GAS engine? Not something I would have done!

 

"Fleet" HDMO's are not just for diesels. They are also API SN as well as CJ-4. What they are not is For Gasoline Engines "Donut" ISLAC GF-5. Rotella T is currently in my motorcycle as it is also JASO MA rated for wet clutches.

 

Thanks for the info on the motorcycle app. I guess I'll have to look the next time I'm in WallyWorld. Is there a specific Rotella T for Motorcycles? Or are all JASO rated?
Craig

 

Both the dino and syn are JASO MA. No, its not a special motorcycle formula, and thats the point, available anywhere and cheap. My favorite HDMO, Chevron Delo 400 is not. Apparently the moly in the formula may cause wet clutch slippage. Also, the 1200ppm or so of ZDDP is good for transmission gears.

 

I was at Wally World today & I see both the Rotella T Dino & Full Synthetic are JASO MA. The Semi Syn. is a JASO DH2. What ever that is. My Suzuki owners manual says JASO MA. or SH/SJ but it says DO NOT USE Energy Conserving Oil. So from what I read You can run any oil with an SH/SJ as long as it isn't Energy Conserving Oil. JASO stands for (Japaneses Automotive Standard Oils). They have two classifications MA & MB.
Sorry about high jacking this thread.
But this thread will save me a bunch of money on Motorcycle Oils. Because I do run Synthetic in it & have from the beginning, Most of oils for motorcycles are $10-$15/Quart. Rotella T 15-40 FULL SYN. is $20/ gal.
Thanks again Jim & Greenheadkiller for this post & Comments.
Craig

 

The reason you cant run energy conserving oils is that they are friction modified, which causes wet plate clutches to slip. 5W-15 Rotella T6 synthetic is what a friend with a race team runs in the track bikes. Shell's XHVI Group III+ in it is the same proprietary base oil that is in Pennzoil Ultra and Helix Ultra (Ferrari factory fill), but at a bargain price packaged for the fleet market.

 

That's what I ran in my 1800 goldwing right out the box.

 

Synthetics really shine for extended drain intervals and very cold weather pour points...other than that, you won't notice any difference compared to running a dino oil.

 

So....... All I would gain from a syn is drain time ( more miles?), does it protect the engine better? Heard it does, I have a Excursion 7.3 PSD- & have been thinking about switching, I have been using Motorcr so far, plus with Tx being in the 100...... Would there be any other advantages