5W-30 vs 15W-40

[Rick_Johnson]

Greetings,

As an equipment tech for a state agency, I would like to hear your opinion on a suggestion being considered (not by me) to change from the manufactured oil recommendations of 5W-30 and 5W-20 to the “good ‘ol Delo 400” or 15W-40 oil to be installed in our fleet of various makes and models of mainly American brands….from 4.0 L Chevys to V-10 F450s. It has been suggested (not by me) to do this change over after the vehicle is off warranty. My concern and objection is the extreme duty and climate of eastern Washington where the temperature can vary from minus 30 degrees in the winter to over 105 degrees in the summer. We have a variety of vehicles in our fleet that I take care of…little pool vehicle sedans, forester half ton 4 wheel drive trucks and some 1 ton pumper trucks in the fire program. Our agency fleet does have a “revolving fund” set up to replace vehicles at 100k miles utilizing the monthly rental rate that funds the replacement cost of each vehicle. I have now received emails of stories on how amazingly the engine life has increased 100k miles with no oil consumption after using 15W-40 oil, but my guess is I can find 100 more success stories of increased engine life- and mileage from those who stayed with, for example a 5W-20 oil. Do you believe there would be any significant benefit by switching to a heavier, oil or could there possibly be problems associated with a heavier oil being used in some engines? My recommendation at this point (with our fleet) would be to stay with the manufacture’s recommended oil viscosity.

Thanks much for your time,

Rick Johnson

 

[TallPaul]

I like your idea of going to HDEO, but 15w40 probably a bit too heavy for winter in your area. I suggest a good 10w30 HDEO. It is available, not easily for the average Joe, but if you are buying bulk, it will be easy to obtain. I can get Motorcraft HDEO in 10w30 quarts at Murrays, but not sure the other CSK stores have picked up on that.

 

[Drew99GT]

What is the oil change interval you are using and the duty service of the vehicles for the most part?

If you could, I'd do the best of both worlds. 5w-30 from say Oct-March and either a 15w-40 or 10w-30 from May-Sep. But bulk pricing/storing would likely offset that plan.

What about Rotella 5w-40, or would that be too expensive?

Ir, another option for one oil would be Rotella 10w-30 - I bet you could find that easily in bulk. That would be a great compromise between price, cold weather performance, hot weather protection etc. compared to 15w-40. I wouldn't want to be using 15w-40 in -30 degree weather in a Ford that specs 5w-20 Anything with VVT (variable valve timing), and the VVT wouldn't even work.

 

[Gary Allan]

Quote:
My recommendation at this point (with our fleet) would be to stay with the manufacture’s recommended oil viscosity.


That's usually the best.

As far as engine life, outside of design flaws/characteristics (and assuming the vehicle is properly spec'd for the service), longevity variances are with the operators.

 

[BrianWC]

Rick,
Have you contacted the US Forest Service fleet managers in Oregon to see what they are using? They have a very similar fleet makeup and may have a good strategy in place already. Of course, we are being mandated from D.C. to make all sorts of changes to our agency to "reduce our footprint" right now and fleet is the first in line for changes. So, things ARE in flux, but...they may be good to ask. Or even the USDA FS folks in California or even Cal Fire?

For what it's worth, my forest down here in Louisiana always go with manufacturer's specs for oil grade. We have been encouraged to use manufacturer specs for change interval but nearly everyone except me goes by the 3 month/3k mile interval. Granted, a lot of our vehicles fall under severe service categories so it's not that bad of an idea....

 

[Quest]

Originally Posted By: Rick_Johnson
Greetings,

As an equipment tech for a state agency, I would like to hear your opinion on a suggestion being considered (not by me) to change from the manufactured oil recommendations of 5W-30 and 5W-20 to the “good ‘ol Delo 400” or 15W-40 oil to be installed in our fleet of various makes and models of mainly American brands….from 4.0 L Chevys to V-10 F450s. It has been suggested (not by me) to do this change over after the vehicle is off warranty. My concern and objection is the extreme duty and climate of eastern Washington where the temperature can vary from minus 30 degrees in the winter to over 105 degrees in the summer. We have a variety of vehicles in our fleet that I take care of…little pool vehicle sedans, forester half ton 4 wheel drive trucks and some 1 ton pumper trucks in the fire program. Our agency fleet does have a “revolving fund” set up to replace vehicles at 100k miles utilizing the monthly rental rate that funds the replacement cost of each vehicle. I have now received emails of stories on how amazingly the engine life has increased 100k miles with no oil consumption after using 15W-40 oil, but my guess is I can find 100 more success stories of increased engine life- and mileage from those who stayed with, for example a 5W-20 oil. Do you believe there would be any significant benefit by switching to a heavier, oil or could there possibly be problems associated with a heavier oil being used in some engines? My recommendation at this point (with our fleet) would be to stay with the manufacture’s recommended oil viscosity.

Thanks much for your time,

Rick Johnson




Of all the things going on on the internet(rumours, unsubstantiated claims, hearsays, etc.), one thing that certainly doesn't chime my bell would be the "thicker is better" crowd.

NAmerica and a few other industralised countries have the best automotive oil available out in the market, and for most multi-viscosity grade motor oil are fairly shear-stable, as compared to those "so-called" multiviscosity oil sold in developing countries where a 20W50 may shear down to 10W40 or so.

Stay with 10W30 or 5W30 if possible and get some seriously good quality conventional oil whenever possible. No need to go full-out on full-syn for it doesn't make economic benefits with the cost associated with it.

Q.

 

[GMFan]

15w40 isn't ideal for winter conditions, and most service vehicles see lots of short trips. The thinner oil would be more ideal. With the HDEO 10w30 you would get the benefits of a thinner oil for cold conditions, and the added detergents.

I'd say a good 10w30 HDEO like Shell Rotella.

 

[JHZR2]

If you want to go that kind of route, Id look for a good 5w-40 HDEO. They are "synthetic" so the up-front cost is higher, but it may allow you to go for longer drain intervals, offsetting cost.

The question is if cost or logistics is really the driver. if it is logistics, then Id say that a 5w-40 is the way to go, as it is only marginally thicker than what most cars call for , it is sufficient for cold winter use, and provides the correct protection for HD engines in the heat of summer.

If the question is regarding higher levels of protection, many engines in many different utilization schemes can see protection that is superior from a heavier oil. it is certainly not unheard of, and again, 5w-40 is a good pick.

if logistics is not the main driver, and cost and simplicity is, then you might want to switch to having just, say, two oils... perhaps a 10w-30 and a 15w-40 (both HDEO, so they can be used for your heavy duty stuff too), or even a 5w-40 and a 15w-40. It all depends upon how real your wintertime requirement is. If -30 is a key metric for selection, it would influence the choice significantly compared to if it was just a minor thing with most engines being on block heaters in the winter anyway, for example...

More insight would help us help you.

JMH

 

[Frank D]

My company used 15w40 in all vehicles year round with 6 month intervals in NYC and Westchester for 30 plus years until switching to synthetic 2 years ago to go to once a year intervals, without any problems. Trannys, alternators, fuel pumps etc go but rarely does a motor go.

 

[JHZR2]

yeah, its just that -30 value that creates and issue. Cars that actually have a viscosity vs. temperature chart generally only ever show a 15w- oil good for temperatures down to 0F. Fine for NYC, fine for where I live in NJ, but not necessarily good for Eastern WA where it gets to -30.

Now for how long and how often is the question that begs for information...

JMH

 

[mechtech2]

That '15' will be rough in temps below 10 deg F.
Also, there will be some increased fuel use with the thicker oil .

I have used 20-50 all year round in Chicago area winters in a number of cars. It was ill informed , ignorant, and bordering on stupid.

 

[coffee]

I cannot seem to locate any HDEO 10w30 in the Phoenix area but I imagine we would have to have a distributor somewhere in the valley. I would love to use this year around if possible but need to find a source.

 

[twigdog]

Coffee, VR1 10w30 is pretty easy to find and it ran well in my 84 volvo.

 

[TallPaul]

And VR1 has (according to the product data sheet) HDEO zddp levels!

 

[crazyoildude]

15w40 in a ford modular engine i have seen blow apart oil filters more than one time in the winter months. Stay with what the engine builders spec they really know what is right for the engine we rebuilt a dodge hemi with 33,000 easy miles on it this past week customer used 20w50 thinking thicker was better than the 5w20 and you know he was right it was better for us as engine rebuilders. Thin is in with engine oil the bearing clearances are so tight on todays engines that thick oil cant get to the middle of the bearings fast enough and that scores the bearing and crank.If it says 5w20 than why not use it maybe a 5w30 in a pinch but 5w20 is a great oil, Period!

 

[Audi Junkie]

I'd identify vehicles that have increased consumption and fill them with 15w-40. They can be topped-off with anything, but 15w-40 fill will reduce the chance of dry engine damage and reduce the amount of topping service needed.

 

[Bryanccfshr]

I see no reason to run an HDEO in a vehicle that does not call for it. I would run the manufacturers specs as originally recomended. An added benefit is you will have a cost savings on fuel used compared to a 15w40.

 

[Ponch]

How will 15w40 reduce the chance of dry engine damage? Are you implying that the thicker heavier oil will cling to the engine internals better?

 

[hate2work]

Rick-

Given the huge temp difference you guys experience between seasons, you should run a thinner oil in the winter, and a thicker oil in the summer.

Just so you know the W stands for Winter, not weight. So the first number determines/describes the cold flow properties of a given oil, and the second number determines/describes the hot flow properties of the oil. IMO, ideally you should probably be using a 5W - 30 in the colder months and a 10W - 40 in the hotter times.

Have you looked at synthetics? The cost is higher but the OC intervals are longer, which of course means less down time for the vehicles.

 

[Audi Junkie]

I mean the engine oil level running "dry". With a fleet vehicle, it could easily go critical. The sooner these vehicles are identified and switched to 15w-40, the better....it will burn less.