5W-30 vs 15W-40

[Bryanccfshr]

Hood plunger devices tied into a driveright system to monitor the drivers periodic checking of oil levels(can be programed into company driving procedure)solves run dry situyations. Driver behavior is now easy to monitor with driveright systems and it adlso assures gentle use. http://www.davisnet.com/drive/

http://www.carchip.com/Product_Docs/8246_Specs_CarChipFleet.pdf

When vehicles are brought in for service the drivers performance can be downloaded and the information used to control driver behavior. This can even be used to pit departments against each other rewarding good drivers and exposing bad.
I have been part of the implementation of this system for company vehicles in my field and the results are great.

 

[mva]

Stick with the OEM recommended grades 5W20 and 5W30 and recommended oil change intervals. This is what the engines have been designed to use.

Going to 15W40 will probably be ok in the summer but why take the risk?

You will have no issues making 100,000 miles and you will save a significant amount of fuel over a fleet of vehicles.

 

[mva]

Please let me explain a little more:

As an engine is started, the oil is at the ambient temperature. If it around -0 F or less and you are running 15W40, the oil will not flow very well and the motor will be starting with poor lubrication.

As the vehicle warms up, it will take about 10 to 15 minutes for the oil to reach a stable operating temperature in the range of 150F to 200F. In the meantime the 15W40 puts a lot of drag on the motor and it will burn more fuel than one running a 5W20 or 5W30 oil. This will occur to some extent year around because a typical 15W40 will be twice as thick or at least double the viscosity of a 5W30 even at 40C (150F).

Compare these specifications for a good quality synthetic blend at 5W20 verses 15W40. Straight dino oil in these grades will be even thicker at cold temperatures:

http://www.pzlqs.com/Tech/Pdsheet/DomesticMarketing/EngineOils/pdf/SUVTruckMinivanMotorOil.PDF

The pour point or minimum temperature at which this brand of oil will flow is about -44F (-42C) for a 5W20 verses -13F (-25C)for this 15W40. You do not want to be starting an engine anywhere near or below the pour point, if you want it to last.

There is also no evidence that thicker oil will reduce wear on a year around basis. Check out the used oil analysis section of this forum and you will find many people experiencing low wear rates with 5W20 and 5W30 oils.

 

[JHZR2]

All of this discussion is good, but I think it still comes back to the question I posed previously... Why?

If it is a logistics issue - desiring to stock only one oil for simplicity, IMO a 5w-40 will fit the bill and not caue any of the issues mentioned in any application.

If cost is the driver, then it really is a no-go, as the engines that can take a 15w- oil at 0F (or can do it in a pinch down to -30) are different than those which need a 5w-30.

Im not concerned with the second number, but rather the first.

From an inventory and logistics standpoint, 5w-40 all the way. From a cost standpoint, 5w-40 will cost you more, so stick with spec. You can get away with a 15w-40 and a 5w-30 only, more than likely.

 

[mva]

Yes...JHZR2 why?

Why go to 15W40 in an area that experiences -30F? -30F is well below the pour point of 15W40.

Why use 15W40 which is designed for diesel engines in gasoline engines which have been designed for optimum performance and efficiency with the use of 5W20 and 5W30 oils?

5W40 will be ok in the winter but the original poster's fleet of vehicles will burn more fuel and the oil will cost more than the 5W20 or 5W30. Why go there?

 

[Lazy JW]

Originally Posted By: Rick_Johnson
....

....replace vehicles at 100k miles utilizing the monthly rental rate that funds the replacement cost of each vehicle.....


Don't even bother changing the oil.....

 

[JHZR2]

Originally Posted By: mva

Why use 15W40 which is designed for diesel engines in gasoline engines which have been designed for optimum performance and efficiency with the use of 5W20 and 5W30 oils?

5W40 will be ok in the winter but the original poster's fleet of vehicles will burn more fuel and the oil will cost more than the 5W20 or 5W30. Why go there?


Well, I think the fact that 15w40 oils are typically considered fleet oils, at least back in the day means that it certainly could be used, in some applications as a universal lubricant.

I think that few would have issue with using solely a 15w40 (despite the increased consumption) in Arizona. Its just that nagging -30 issue...

 

[bulwnkl]

A 15W40 would be a very, very poor choice in a modular Ford.

Our fleet uses 5W20 and 5W30 (as the manufacturers specify) year-round. Unlike eastern WA, eastern ID genuinely sees those low temps most winters (rather than a couple times in a lifetime. I know, I lived there 30 years

). We don't see many days above 95, though.

We have no issues stocking 2 oil grades, and we have considered switching to all xW20 oils. We run analysis on the fleet, and we're even running RLI.

Our fleet sees sevice conditions at least as rough as our sister agency, the FS, does. We're happy with what we're using, and we're not foolish enough to run 15W40 (except in the tractors, of course!).

 

[Nickdfresh]

Forgive me if this has been mentioned, but it seems the fuel economy loss resulting from the switch to a heavier oil would also pose a problem.

 

[Ramblin Fever]

I personally believe that a 15w-40 only holds a need for being ran in diesel engines or tractors.

Don't see the need to run such a thick oil in regular gasoline engines.