Ok my 95 psd has 151,000 miles and runs great. I haven't had the truck long but I switched it to the rotella 5w-40 t6 fully synthetic with a Mobil 1 filter and was planning on going 6-8000 miles between changes. I am at a little more than 3000 miles now and I am down almost a quart of oil. Just wondering if that seems normal to you guys for the truck to be down that much with that mileage. Also it doesn't leak an ounce of oil from anywhere. Thanks in advance for any input.

 

Before I comment on the oil consumption, I'll ask a couple questions.

1. Was the truck on a "perfectly" level surface when you checked the oil?
(being a little off level can make a big difference in the reading you get)

2. How much oil did you put in when you changed it?

3. Have you been driving it empty, or have you pulled any loads?

 

Sometimes changing from what oil the motor was formerly using to a completely different oil can cause oil stability problems as you mention.

such as using conventional oil for 75% of the motors life and then changing to a full synthetic.

From what I have read, its recommended to stick with the same oil type if the during the lifecycle of the engine "X" type of oil was used exclusively.
Some of these older engines' internals are just not engineered for full syn oils
stability becomes a problem
Have you tried regular 5W-30 and made a note of the oil control with that oil type ?

 

BTW, I use the Motorcraft 15w40 conventional oil. It is excellent oil.

I have 324,000 miles on my truck and it will only use a little bit (1quart) per 4000 miles if I am pulling a pretty good load (8-10,000lbs)

 

The truck was level everytime i checked it. I check it alot lol. When I changed the oil I put three and a half one gallon jugs. Started it and let it run for a bit then topped it off so it was perfect. So i would say about 14-15 quarts. As for towing I have pulled a 4-5k trailler a couple of times( not too far though) and had the bed filled with wood a couple times on a 200 mile trip. Most of the miles are highway. Now I dnt know what the previous 4 owners use to run in it but the first 3 oil changes i did was with dyno oil mobil delvac 15w-40 and it use to be down a quart when i changed it every 4k. That was one of thereasons I switched to sythetic cuz I heard it is more resistant to oil consumption.

 

I think that every engine responds differently to different oil.

Sometimes synthetic will not have as much consumption over X amount of time, sometimes it seems to be more. I am not an expert on different kinds of oil, but if I were you, next oil change I would try the Motorcraft 15w40 conv. oil. just my .02

It is not at all related to oil consumption, but it is always a good idea to prefill the oil filter.

 

woooeeeeeyy, your racking up the miles on that old girl going to top my miles soon, you got that beast the beggiing of the year at what 143k? LOL and its been down most of the time, hahaha

jk, but like i said, dont worry about a quart, you ream on that thing haha

 

Both of the oils will have no effect on oil consumption. The engine burning the oil is a mechanical issue, weather it's the rings/cyl walls, valve guides/seals, misc leaks. 1 qt over 3k miles isn't that big of a deal at all. I'd run it out to a 6500 mile oil change though.

 

On your next oil change switch to a 15W-40 synthetic, a 5W motor oil is a little thin in these engines. The recommended oil is a straight 30W or the 15W-40 Marine/Diesel HD.

I run the Amsoil 15W-40 Marine/Diesel HD. My truck runs GREAT! Best Wishes!

B

 

Yes I always fill that garbage can of an oil filter up to the top before I screw it on lol. Steve I barely drive that thing and when I do I baby her lol. Thanks guys for your .02 keep your input coming.

 

Oh yea and I forgot Steve I got it February with 143k and it wasnt down most of the time only at the body shop for a month lol. Also obviously I'm going to pass your miles cuz you only drive in town lol you just rack them up on other guys rigs lol.

 

5W40 is only a 5w when it's cold...when it gets warm it's a 40 weight...so a 15w40 end up being 40 weight. Ford recommends oils based on temps...15w40 (above 0*), 10w30 (-10*F-90*F) and 5w30(below 50*F). Using a 5w40 will cause no harm to these trucks.

 

The 5W oils are used in the newer engines that have much tighter machined tolerances, so the oil flows quicker and at lower temps.

I have only seen a straight 30W or 15W-40 oils recommended for these engines.

I ran a 5W-40 oil in a '80 Mercedes 300D & had a low oil pressure problem that was traced to using the 5W oil.

I would never run a 5W oil in these engines!

Thanks,

B

 

The recommendations I have are right out of the Powerstroke supplemental manual that came with the truck. It's also posted in Fords' service manual for the 7.3l Powerstroke engine. Like I said, it's only a 5w, 10w or 15w until the engine is warm. Ford lists no recommendation on straight 30. Most engines are pretty close to each other on rod and main bearing clearance...you can only run them so tight.