i work for a body shop, and theres a service shop connected to it, i was talkin to a mechanic about me needing to change my oil and he said that he runs 15w 40 in his explorer, and my boss runs the same in his jeep and another guy in his dodge 1500. because of how thick and lubricating it is, also quiets down engine noise. im no mechanic so i want to no if this is SAFE, if it will cause immediate damage, or long term rotting on any seals or ANYTHING like that. am holding off on an oil change until i learn more. i don't want to put anything harmful in my truck. its a 95 f150 xl. 4.9l auto

 

This is a touchy subject. I'd run Rotella specifically since its ZDDP level is still above other gasser oils. Not in the 1200 ppm range, but around 1000ppm's. That's still good for the 4.9...but I wouldn't run it with night time winter temps in the 20's without a block heater. The 4.9 has exhibited a much harder time getting oil up to the lifters and I've read several posts concerning how they love to eat oil pumps.

There is also a lot more detergents in diesel rated oil, whether it be Rotella, Delo or other brand. Check out Bobistheoilguy.com forum for more info. If there isn't any wrong with your truck now, I'd stick with either Dino Pennzoil or Quaker State Defy. Pennz has higher levels of ZDDP and Moly, and the Defy has higher ZDDP for added wear protection in older vehicles and plenty for properly broke-in flat tappet cam engines. I also believe it is Synthetic blend as well. 5 quarts last year was $14. I'm unsure of its price now. Its still a safer alternative to running 15w-40 and cheaper than Rotella.

Edit: Pennzoil has the higher number of ZDDP in the newest class of API SN rated motor oil, with the certified API Starbust on the container.
If I have provided erroneous info regarding Pennzoil, could someone post the new info regarding the Moly and ZDDP level. Thanks, Matthew

 

well, with this new info i guess the question is, is it worth it for my 160k motor to run this rotella,? or just to stick with the traditional 10w 30 type oil? is there any benefits to running the diesel oil? if they put stress on my oil pump that don't sound good.

 

I have run rotella in my 5.0 for 2 oil changes now with-out issue and I live in Canada were minus 25-30 over night is pretty common. Mind you I just put in a new starter which feels like it has more power than a diesel engine but I still have had zero issues. Your motor will be pretty clean after you use such oil as well and the first change comes out looking like black pen ink haha.

 

I've included this link from the site I mentioned in my previous post. Please take a moment to visit the link and read through it carefully.
Matthew

Whats too cold for 15w-40? - Bob Is The Oil Guy

 

Most speed shops sell ZDDP additivs, which is what I use in addition to my off the self valvoline

 

I run 15W40 diesel oil in my vehicles(89 F250, 95 E350 and my 85 Plymouth) for years with no problems.

When it's free engine oil can't be picky about it........LOL

 

I have a 1992, 5.8 liter and have been running Rotella 15W 40 for over two years without issue but I live in Canada and do switch back to 10W 30 during the late fall and winter.

I does seem to help in the warmer weather and so far no issues.

 

well i live in south east michigan, and temps get pretty low here in winter (not -20 low but maybe 10 or so) so what yall are saying is that i should be fine using 15w40 year round, maybe adding some zddp? and what about motorcraft 15w 40 for powerstroke diesel? they have it for 20 buck for 5 qts, but it says not for use in gas engines with CATALYST, and under my hood theres a sticker that says CATALYST...what does this mean? im leaning toward using the diesel oil now because i have the i-6 motor and its only got 160k and if this diesel oil with lube it up more and like u said, actually clean up my motor, then its worth it.

 

i run 15w-40 rotella in my 84 because of the high mileage it helps keep the worn out parts lubricated. although i run 10w-30 valvoline vr1 full synthetic in my 97. the vr1 also has high zddp. and for what its worth i run the conventional vr1 5w-50 in my race car cause that what the engine builder has me use.

 

I use 10w-40 Havoline oil year round. Oils are a weird subject because everybody does different things and it all works for them.

 

Diesel oil is safe to run in a gas engine, though I wouldn't run it year round, diesel oil is like molasses in winter, literally.

If you have a dirty gasser engine, run diesel oil in it for a few oil changes, and cut the changes to 2k miles for that time. It'll clean it up real good.

Diesel oil is full of detergent, and contains alot of zinc as well as other anti wear properties.


Now for those who say you haven't had problems with it running diesel oil in a gasser in cold winter temps....have you opened up your engine to see your bearings? Bet'cha if you did, they'd be worn down to the copper! Diesel oil is so thick in winter, it doesn't start lubbing tighter clearances till it warms up abit, so the bearings wear down pretty quiclkly until theres a big enough gap that the diesel oil can lube it right away.


In winter time, I ran Diesel specific 10W30 in my 7.3 since it was new. Helps with cold starts, and gets circulated right away. 377k miles on that thing, and the heads have never even been off the engine!

Another old trick to cleaning an old dirty engine is running abit of ATF in it. Say your truck takes 6 quarts, put 5 quarts of motor oil, and 1 quart of ATF (any kind but type F), or for a really dirty engine, half and half, and dump it after 1k miles. Repeat till oil drains clean!

 

I have only ran it for the last two oil changes to see if it would clean it up like everyone says and judging by what the first change looked like at 3000km I have to agree now. It was minus 34 this morning with the wind and it started on the 2nd turn over with-out issue. It's much quieter on cold starts with the heavy oil though.

 

i have been running valvoline all fleet 15-40 in all my engines for the past 40 years.
never had any problems. the 273 in my 66 W-300 had 640,000 miles on it when the body fell off it.
we pulled the engine, freshened it up and put it in an irrigation pump. that was 30 years ago and it is still running, and also still running all fleet for oil.

 

180k and i run motorcraft 10-40