Oil Experts, Viscosity HELP! 1

[ssg1]

We have extreme difficulty obtaining the proper recommended 15/40 oil for our diesel vehicles and generators.
We have straight 10 and 30 weight oil.
Question: Can we use, say, 30 weight oil in our diesels?
This would be long term, like months at a time, until we can get the proper grade. Would un-repairable harm be caused? Can we use it in this 120F daytime heat?
We could use an answere ASAP. Thanks!

 

[rmw]

Look carefully at your engine manufacturers recommendations. Sometimes, for "fixed" climates, that is to say consistantly hot, or consistantly cold (doesn't sound like your case) climates, they permit the use of single viscosity oils.

In your case, based on no more than you state, although I think I can guess where you are, the highest viscosity oil you can get should be used in the absence of the recommended 15/40. (The 30 wt.) Remember the basic recommendations are made at the manufacturer, not knowing where their products are going. The sister (engine/generator, whatever) to your units could well have been sent to Alaska. Or an engine can start a trip in Houston, and end up in "way north falls, Minnesota", experiencing a wide temperature variation along the way.

Your multigrade oil is basically 15 wt oil with polymers added that increase the viscosity to 40 wt in the presence of heat. These polymers shear and otherwise break down over time, and the oil reverts back to the minimum wt, which could be dangerous in your climate. There are experts on this forum who can elaborate on this much better than I can with my limited understanding.

I personally speaking, and living in the southern USA, where it is almost always hot, I would not hesitate to use the 30W in your situation, and if I could find some 40W, I would use it instead. My opinion, do not use the 10 wt oil in the situation you describe.

Also, don't mix the single grades, and the multi-grades.

But, most importantly, read those technical manuals over once again, and see if they have any recommendations for non standard operation, or go to the website of the engine manufacturer, and look for a technical question section and post your situation there. What I have said is my opinion only!!!!

rmw

 

[enginebob]

Most all manufactures print operation manuals for their engines. And in those manuals are tables of what the approved viscosity oils are, and for the various ambient temperatures.
What size engines are these? And what manufacture?
How many hours on them now?
In those temperatures SAE 40 would probably be the way to go. But as long as the engine operating temps are maintained at the 180 or so degree point. The SAE 30 should be fine. But if these engines are under a warranty I think your best bet would be a phone call to the manufacture. And get their opinion. And make sure it is heavy duty oil designed for diesel engines!!

 

[ssg1]

Thanks for the prompt replies!
(1) Military vehicles: 6.5L and some 6.2L AM General
turbo-Diesel Humvees. Our manual recommends 15/40. Problem: we cannot get it. War and all. Unknown hours: Estimated at 2 to 18 hours per day for at least(known) the past year, probably longer.(= 730 to 4400) in extremely hard conditions.
Vehicle temp gages routinely run into 220 and daytime past 240. Yes, not a typo. Engine heat then hits us because idiots who designed and issued the damn things dont seem to have thought of heat shielding.
(2) Assorted scrounged vehicles of many makes/models with diesels:
Unknown hours or owners manuals nonexistant.
Assume similar history as above or worse knowing Arab maintenance.
(3) Assorted scrounged diesel generators, unknown origin. Covered in oil. Makeshift parts/bailing wire, etc.
Ran/Running sometimes 24/7 for at least the past year. Assume outrageously long hours in high daytime heat. No temp gages on engines. Shutdown is initiated every time an engine spews steam/coolant. Happens often. Switch to another if its working.

Conclusion: Do not use 10 weight. (Why issue it?)
It would seem impossible to hold engine temps
in the 180s, no way around it. So do not use
the 30 weight?

 

[franzh]

I agree with the above, with my tag:
Why issue the 10 wt? Its in inventory, and most likely due to standing orders about deployment, as my son says (US Army AB Ranger SO) "plan for any contingency" prevails. The RDF plans for cold and hot climates.

My recommendation: Use the 30wt as a minimum in anything possible and watch any available oil pressure gauge for low swings. Use 40wt in unknown older equipment, with any viscosity improver (STP, Motor Honey) in equipment that shows pressure fluctuations. I would think that you might find more than a little 90-140 diff lube in some of your salvaged equipment. Lots of it comes from China.

Lastly: As a proud father of a US Army Soldier, may I offer my support to you in any way I can, lets hope the others do also.

Franz

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[rmw]

Agreed with Franz, use the 30 wt, and forget the 10 Wt. in that climate. Since 40 wt has not yet been mentioned, I assume you are recommending to him to scrounge some. I concur, as long as enginebob's recommendation to make sure that it is a grade for diesel service, and with all the qualifiers his engines call for. I have lost track of all the grade designators-shows how far behind I am for diesel oil these days.

If you don't have the best grades, some of the stationary equipment might stand the lesser grades better than the automotive equipment.

But, Whoa!!!, Franz, where did 90-140 diff lube get in the conversation???

I assumed we were talking strictly engines. Please clarify if you meant to recommend 90-140 diff lube or was it a slip of the mind/finger connection, as I have done several times in this forum.

I just don't want the thread starter to get the wrong idea if you weren't specifically recommending that, and I have never heard of diff lube being used in an engine, but I can learn if that is what you meant.

Plus, ssg1, check your gearbox lubes supplies, and you might find some straight 50W engine oil, since that is recommended in a lot of gear boxes in lieu of 90w or 90-140w. In your situation, and old abused equipment, I would not hesitate for a moment to use that in a suffering engine.

Sounds like you are in a mess.

rmw

 

[franzh]

Actually, the 15/40 was mentioned, but not available. I have seen 90/140 in some real tired engines, mostly stationary gen-sets or irrigiation pumps. Its nasty, smells worse, and if the equipment our SSgt mentions is in as bad condition as he states, I wouldnt be surprised if its there. I would bet money on it!
This is by no means a recommendation, just a FYI and a CYA. Those are military acronyms!

In those climates (remember, at night it can get into the 50's in areas on the desert(, I would rather see 30wt, but would tolerate 40 wt for the extreme heat.
Franz

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[rmw]

They may be military acronyms, but they are sure part of my venacular, and I have been a civilian again for almost 40 years, now.

I thought they were engineering terms.

Just a heads up!!

Thanks for the clarification. I though the diff lubes had some sulphur or maybe phosporous compounds that were real detrimental to certain engine parts, not that I wouldn't try anything to save a 'tired' engine in a 'have to' situation.

And, depending upon the engine, especially the stationary engines, if any of them are old Detroits, they took straight 40 wt, and they did not recommend 15w/40. I still operate one of those, and straight 40 wt has become hard to find in the truck stops anymore. So, yes, rather than toasting an engine, I have used 30 wt when that was all I could buy. So I don't want to appear too straight laced about it.

I once put straight diesel in a VW engine to get the sludge in the bottom of the sump broken up enough to drain the engine. The diesel cleaned up the engine real good, and the it gave me years of good service. I can still see the service station attendants face as he was attempting to explain to me that my car was a gasoline car (I was a college student who I am sure he thought knew nothing) and I said, 'oh no, I don't want it in the gas tank, I want it in the oil filler port.'

rmw

 

[Majik]

Being that we've built over 300 6.2 and 6.5L engines for the army after the first desert skirmish in 91 I will assure you that using SAE 30wt wouldn't hurt a damn thing... you could use it when it's 30F outside and you'll just have really good oil pressure.. atleast let it warm up a little when it's really cold... and put some extra cooling on them things or you're gonna be putting crack repair sleves in those heads.... 6.2's and 6.5's are very tolerant of which oil grade.. if you've got the 6.5T's out there give them thicker stuff cause I know they're gonna have some EGT issues in that heat... a PFC cooler (doubt you can get them) and removing all the exess plastic on the engine will help immensly on keeping them cool (not sure if mil regs will let you) and if ya need some parts we ship world wide ;-) Keep up the good work. We're proud of you.

Kris

 

[rmw]

ssg1,

If you are still following this thread, I found a great link on a bus owners site. (I am still trying to nurse an old 6V92 TA down the road, with few sources of straight 40wt available in the truck stops anymore, so your thread was of great interest to me.)

http://www.detroitdiesel.com/public/technicianguides/technav.asp

You may not have DDA engines, but there is a lot of technical information you can "mine" from that site. I gave you the whole site, because it might be a resource for the overall job you have to do over there, not just engine oils.

The specific one I recommend for you to look at is;

http://www.detroitdiesel.com/public/technicianguides/7se270.pdf

Note what they have to say about the level of sulfur in the fuel vs oil requirements. I would suspect that the fuel you are getting over there is not made by the US EPA, and may not be the low sulfur stuff we get back home.

Also note what they have to say about some military grades of oils in the latter pages of the PDF.

I suspect that each of your engine manufacturers represented in your 'fleet' has such a website, but this is the one I need to know about.

I hope this helps.

rmw

 

[ssg1]

Sirs/(Ma'am):
Thank you one all for your information! You have been extremely helpful! I appreciate your assistance.
We have been busy, took a bit to reply back.
We ran out of MilPrf2106 30wght. However, I found a stash of 80/90 gear oil. I might use that in the local generators since I dont care if they burn out but I am still looking for something for the Humvees. I cant afford to ruin them just yet since we are SOL if we lose them.
Others might have access to the proper items but where we are at we are kind of on our own.
Again, thanks for your support!