M939 Oil Change, Best Oil, Tips and Tricks

[99nouns]

I just first time going to change my oil on my M927-A2 and I know, A-1 and A-2 are little different in procedures, but I really wanted to put up decent newbie reference and question platform for all the opinions and options so where other people can ask their questions under one thread.

I have changed oil before, never diesel, my general procedure as follows.

1-Add motor flush run engine for 5 mins.
2-Open drain plugs, let it drip long time.
3-Remove filters, clean housings.
4-Fill new filter with oil apply oil to gaskets and install, dont over tighten.
5-Put on oil plugs back on and fill with oil.
6-Run engine 5 mins, shut engine 10 mins check oil again.
7-Check oil again next day, add as necessary.

Please feel free to point out any mistakes above but my main question is what oil should I use.

So manual TM 9-2320-272-10 pdf page 67 or paper page 0002-15 says



So I take that as 15-40 oil for engine,
but what brand without holing the pocket and what does OE/HDO stands for?

I saw in the wally world all,
Castrol 15-40 5qt 12.xx
Mobil 15-40 5qt 25.xx
chain part stores were about 10 bucks more

I know Cummins prefers Valvoline as their official oil, and I am confused about the price difference, why so large? What do you use? Any suggestions?

Thanks in advance for the replies...

 

[4x4 Forever]

Everyone has their own idea of which motor oil to use, with very heated discussions of which is best. IMO, For motor oil, on a cummins, DELO 400. Yup, it's Dino, but as your post stated 'without holing the pocket'. You could go syn, but why? How many miles are you going to put on it in a year? If changed once a year because of very very low miles (which I do and suggest), you are spending major $$$ for protection you don't really need.

 

[twisted60]

I run Shell Rotella 15W40 (Heavy Duty not synthetic) in my 923A2. The OE/HDO I believe is Oil Engine/ Heavy Duty Oil, I seam to remember reading it in one of the TM definitions. When you remove the plug from engine pan watch for the washer, mine was very hard to see and got dropped in to drained oil bucket, ya I had to fish it out. As for Wally World I buy my oil where ever it is on sale or lowest price.
Your procedure is sound, on #4 be sure to apply oil to gasket on filter and don't over tighten. #'s 6 and 7 are good, let engine run to circulate oil then shut down and let it settle to get an accurate measurement on dip stick.

Good luck

 

[Cape Coastie]

I agree with both of these guys. Either oil is very good for most of our uses. I used my oil pump bucket that I use all the time for the boats I work on. This just reduces the chance of a major oil spill under the truck when all that warm oil comes shooting out and there is a lot of it. I use a flex flat funnel to guide the oil draining out of the filter housing as I have the original filter on the NHC250. Someone suggested a small plastic kidde pool for catching the oil which isn't a bad idea. Good luck.

 

[Tow4]

You need a big container to catch the oil.

Any heavy truck 15/40 oil will work, they are all good; I buy whats on sale. All of my trucks have had different brands of oil in them over the years with no problems. I usually get Rotella T 15W-40 or Delo 400.

 

[74M35A2]

Synthetic is a waste unless extremely cold temps. I disagree with motor flush, bad historical experiences with it. Use any C-type API starburst rated 15W-40 and you're good. Delo is highly recommended on 2 stroke Detroits due to the shearing action of rings across ports, but for 4 stroke any name brand OK. I work with Cummins daily, and there is no preference to oil brand, though they endorse Valvoline in marketing. What this ends up usually meaning is Valvoline won the bid to fill engines at the end of the Cummins assembly line, and pays Cummins an extra check to use their name as approved on their bottle.

 

[99nouns]

Synthetic is a waste unless extremely cold temps. I disagree with motor flush, bad historical experiences with it. Use any C-type API starburst rated 15W-40 and you're good. Delo is highly recommended on 2 stroke Detroits due to the shearing action of rings across ports, but for 4 stroke any name brand OK. I work with Cummins daily, and there is no preference to oil brand, though the endorse Valvoline in marketing.

I would really appreciate if you had little more input on Motor Flush, I had the logic of thinning the dirty oil to get all the dirt and grime flow easier into pan from all the intricate depressions and slots possibly between moving stuff.

 

[74M35A2]

I think it has a bunch of bad reviews, all over. So much to the point it is difficult to find in stock anymore?

My experience is that it caused a small 4 cylinder of mine to suddenly have a lot of blow by, broken rings, etc....immediately after using it. Also, the can specifically states not to drive with it (engine under load). I think it is essentially kerosene (?). Honestly, your best policy is to just change the oil at the recommended intervals. Some have stated to use ATF if you really feel you need cleaning. I have used a quart of ATF in cars on two separate occasions to cure early morning lifter ticking. It worked both times, and at least it is a lubricant. But honestly, it is really just best to change at or before the change interval. If you want to get more technical on it, you can send your oil out for analysis, it is very low cost to do so, and they can tell you the remaining free detergent availability.

If she is really grungy under the valve cover, then really the best thing to do is refresh the engine with an overhaul.

Each their own, but I kind of rank motor-flush along with the Power Service diesel fuel additive products. It is easy to get excited and want it as it sounds like a great idea, but neither are good for your engine. The Power Service is alcohol, and that is how it absorbs moisture, alcohol is not really good for your injection pump. You will likely not find them endorsed by Cummins or Bosch for use. Starting fluid is not good for an engine either, but yes, I have used it.

 

[Two Stroke Madness]

Unless your engine has been running oil from the 50's then there's no real benefit from flushing it. However if you do still feel inclined to do so Napa sells an engine flush that has the consistency of 5wt oil... Probably your best bet.

 

[Two Stroke Madness]

Synthetic is a waste unless extremely cold temps. I disagree with motor flush, bad historical experiences with it. Use any C-type API starburst rated 15W-40 and you're good. Delo is highly recommended on 2 stroke Detroits due to the shearing action of rings across ports, but for 4 stroke any name brand OK. I work with Cummins daily, and there is no preference to oil brand, though they endorse Valvoline in marketing. What this ends up usually meaning is Valvoline won the bid to fill engines at the end of the Cummins assembly line, and pays Cummins an extra check to use their name as approved on their bottle.

It's not the brand but the numerical reference of the oil that mattered. Chevron Delo CF-2, and CF-4 were produced at the same time. The 2 and 4 does not represent a time scale reference, but rather the application in two or four stroke diesels. Chevrons Delo was prefered for use in two stroke diesels because it had the lowest ash content of any other brand. Two stroke diesels can't tolerate ash.

 

[99nouns]

I think it has a bunch of bad reviews, all over. So much to the point it is difficult to find in stock anymore?

My experience is that it caused a small 4 cylinder of mine to suddenly have a lot of blow by, broken rings, etc....immediately after using it. Also, the can specifically states not to drive with it (engine under load). I think it is essentially kerosene (?). Honestly, your best policy is to just change the oil at the recommended intervals. Some have stated to use ATF if you really feel you need cleaning. I have used a quart of ATF in cars on two separate occasions to cure early morning lifter ticking. It worked both times, and at least it is a lubricant. But honestly, it is really just best to change at or before the change interval. If you want to get more technical on it, you can send your oil out for analysis, it is very low cost to do so, and they can tell you the remaining free detergent availability.

If she is really grungy under the valve cover, then really the best thing to do is refresh the engine with an overhaul.

Each their own, but I kind of rank motor-flush along with the Power Service diesel fuel additive products. It is easy to get excited and want it as it sounds like a great idea, but neither are good for your engine. The Power Service is alcohol, and that is how it absorbs moisture, alcohol is not really good for your injection pump. You will likely not find them endorsed by Cummins or Bosch for use. Starting fluid is not good for an engine either, but yes, I have used it.

Thank you for your input, I am skipping the engine flush, and I think you make sense.

But now you got me wondering about the ATF, do you normally just add it to the engine oil and keep it there or do you use it like a flush where you just add before drain, and how long do you keep it in there for brake down of deposits if any, can you please get little bit more specific on use?

And what about 20% Lucas, is it all hype or is it really a wonder oil where it makes it sticky and reach higher places in engine to prevent dry runs?

 

[simp5782]

If you want cleaner oil that will last longer then upgrade to a bypass oil filter system. The filter unit has a less than 1 micron rating which can captures everything. Most bacteria are 3 micron in size. It will slowly clean all the contaminants out. Also gives you a 25,000 to 40,000 mile oil change interval at the least.

My main pet peeve on changing any oil in any vehicle is to put the oil cap somewhere I will close the hood on it. That way if I get ahead of myself and think I already added oil or didn't check the oil and close the hood it will hit the cap and I will know something is a miss. I have seen a lot of people forget to put oil in their car simply just cause of brainfarts. It happens, we are human. Well some of us are, others are questionable.

I run Rotella 15-40 from wally world or on sale. I never pay more than 12.75 a gallon for it.

I flush engines with just diesel, just don't rev it up. let it idle 5 to 10mins, drain, filter swap and repeat if needed. HOWEVER doing a motor flush can cause a few things the main one being that the screen in the oil pan will get clogged up with loose crap that didn't come out when you drained the oil. Can cause a lifter that wasn't tapping to start tapping. Or it can cause gaskets to start leaking cause some crud on the inside that was built up was actually a good sealant and got washed away and the gaskets just started leaking.

I used to maintain a lot of security company vehicles that simply idled around most of the time. They would sludge up so bad from not being ran around and just idleing. Or even having their oil changed. Long Idle periods are worse on an engine than 5,000miles on an engine.

 

[74M35A2]

99, you're really in a hurry to put something other than motor oil in your engine? What does it look like under the fill cap? I only did the ATF trick to silence lifters that had morning sickness, not on a regular basis. If your engine is not sludged, just change the oil.

 

[Two Stroke Madness]

I would not run any additives in the oil. They tend to change the viscosity of the oil into 15w-?. I ran Lucas oil stabilizer in the transmission and rear end of my 31 Ford model A for one season. I changed it right after I had just got home from a short trip. I was quite surprised to find that the stabilizer had caused the gear oil to foam. The stuff is too sticky, and caused aeration of the oil. And guess what doesn't work very well as a lubricant... air!

 

[Two Stroke Madness]

I would also not add anything to the oil as a means to clean an engine. There's actually a much easier and safer way. Just run a Group V synthetic oil. The esters that make up a Group V synthetic oils base stock also make excellent detergents. Just run a Group V synthetic oil for a season or two and the inside of your engine will be squeaky clean! Be warned of two things however... first- Group V synthetic oils are a very high performance oil, but also very short lived. These oils are not ment for extended oil drain intervals, so bear that in mind. Second- if your engine has any worn seals or shrunk gaskets that are currently being sealed by sludge then when this oil clears all that away leaks will become apparent.

 

[99nouns]

Wes thank you for your input and I am sorry for picking everyone's brain so hard but I have learned by experience that there are little things makes a huge difference.

My life have several mile stones that made a difference like M.E.K, I have a friend who is an airplane engineer and mechanic and I was complaining to him that silicone seals that I apply to roof of my motor home was coming off every 6 month to a year and I was very unhappy with maintenance intervals, and he said they use silicone on airplanes all the time and held up lat more than that under much more harsh conditions of wind, dust and temperature changes, and he said the trick was they wiped all applicable surfaces with MEK and wait 15 minutes before they applied silicone, and now my roof has not leaked for 5 years and I cant even remove the silicone I applied 5 years ago.

And most mechanical failures happen because of somebody either didn't know or short cut a proper procedure and failed, I love my truck and my engine was a recent rebuild before I purchased it and I want it to out last me, so if I follow the right procedure I know it is capable of doing that. And I don't want to be the guy who made that little error and bang his head on the wall... And perhaps I can be the rookie who will help others by asking 100 questions and someone in the future will see these posts and thank all of us for being there.

Like the ATF additive to clean engine, I could have never learned that if I would have never asked, and it is the same these forums where I learned ATF is great paint stripper, it doesn't say that on the box.

Above reasons are why I love this website, it is like a gold pot, you just have to stick your hand in it. Wes has surprised me many times. I sometimes if he dreams his trucks when he sleeps. How does he know so much...

Again thank you all for your inputs...

 

[Steelreaper80]

What oil change intervals are people running with the 8.3? My truck is used as a tow vehicle pulling about 18K out of state multiple times a month. I changed mine at 7K? Too long, too short?

 

[simp5782]

What oil change intervals are people running with the 8.3? My truck is used as a tow vehicle pulling about 18K out of state multiple times a month. I changed mine at 7K? Too long, too short?

Send your oil in for analysis before you change it to see what life is left. Or add a bypass oil filter system that will get out smaller contaminants. I have them for sale.

Sent from my SM-G860P using Tapatalk

 

[74M35A2]

Or simply check the Cummins recommended service intervals for it. They recommend 15,000 miles on an ISC (8.3L), nearly the same engine, but likely that one runs cleaner being a newer design, EFI, etc.... You could probably do 10,000 miles and call it good if you just wanted a simple no-math #. But, it all depends on operating environment. Start-stop, dust, temp, humidity, etc...

Oil analysis is the cheapest way to do it, believe it or not. Oil changes can be expensive, and analysis is super low cost, and they can tell you the % of free detergent remaining available. Just pull a small sample, and mail it off.

 

[99nouns]

Ok İ just finished my oil change and my oil pressure gauge went pass 120 on acceleration and stays around 40 idle, it never pass 100 before, is everything ok with me?