Observation: Mobil 1 0w40 In 5W-30 Application

[Oil Changer]

1999 Chevy Express van, low miles, perfectly maintained, 5.7L. OM recommends 10w30 for 0F and up, 5w30 for all temps, severe cold, synthetic 5w30 or 0W-30.

1. Oil pressure is instantaneous even with the few just above freezing morning temperatures I've had here. I expected higher pressure readings both cold and hot but the gauge reads the same.

2. Fuel economy went UP from 13.5 MPG to 16.6 MPG. My station could have switched from winter blend to summer but have not confirmed nor do I think the attendant would even know.

3. No loss of power, strange noises or other maladies I read here on BITOG that might happen.

Why? Because I had a gift card and it didn't cost me anything so I figure I would drain it if there was problems. Also, for pretty much every application that calls for a 5w30 in NA, the M1 site recommends 0w-40 (which is named "Protection Formula") in Europe, including my van. I will leave it in for my typical interval. That means I will drain it in late October.

 

[pbm]

Mobil 1 0w40 has more manufacturer approvals and is reputed to be one of Mobil's best oils. I would have no problem using it in your application and I would probably go a little further on the OCI.

 

[Trav]

Originally Posted By: Oil Changer
No loss of power, strange noises or other maladies I read here on BITOG that might happen.

Why would there be? 0w40 is spec for most GM in some other countries. 0w40 is a lot thinner cold than some of the old conventional 10w30 that was spec for the SBC years ago.
I remember in the early 70's some 10w30 was even hard to pour out of the can in winter, some didn't flow and blew a lot of engines if they were unfortunate enough to get it running.

 

[wemay]

The viscosity specs for my Hyundai are 5w30 or 10w30. M1 actually recommends AFE 0w30, which is currently being used as of yesterday. I'll get back to you with any observations.

 

[Quattro Pete]

Originally Posted By: Oil Changer
2. Fuel economy went UP from 13.5 MPG to 16.6 MPG.

Sorry, but that is just not happening as a result of switching from 5w30 to 0w-40.

I don't question that your fuel economy went up. It just had nothing to do with the oil.

 

[Merkava_4]

Originally Posted By: Quattro Pete
Originally Posted By: Oil Changer
2. Fuel economy went UP from 13.5 MPG to 16.6 MPG.

Sorry, but that is just not happening as a result of switching from 5w30 to 0w-40.


Why not ? Maybe the 40 weight is lubricating better thus reducing friction. In the used oil analysis section, those Chevy truck V8's always have high wear numbers with 5w30. On 40 weights, the numbers are always way lower.

 

[Quattro Pete]

Originally Posted By: Merkava_4
Why not ? Maybe the 40 weight is lubricating better thus reducing friction.

What is it about the 40-grade oil that is causing it to lubricate better? 40-grade oil has a higher film strength to offer more protection in extreme operating conditions, but that comes at a cost of INCREASED friction - engine is spending more effort on pushing heavier oil around. Granted, these are very miniscule changes, but they are typically changes towards worse fuel economy, not better. Unless the OP was using 20w-50 previously...

Notice, he described a 23% improvement in fuel economy.

Someone should alert GM ASAP - they could be beating their CAFE numbers just by doing away with dexos and recommending 40-grade oils instead.

 

[Oil Changer]

Agreed. If I was to make a point that point would be don't expect drastic fuel economy losses by upping a grade. The only meaningful change made besides the oil is that I'm idling less in the warmer temperatures. Other than that, no changes, which is why I mentioned the fuel blending. I always see MPG improvements when the stations stop selling the oxygenated winter fuel.

 

[Quattro Pete]

Originally Posted By: Oil Changer
The only meaningful change made besides the oil is that I'm idling less in the warmer temperatures.

That right there explains your change in MPG.

 

[Colt45ws]

Yup. I would expect that engine to consume in the neighborhood of 0.5-0.7GPH idling when warmed up. More cold.

 

[Oil Changer]

The oil I had in all winter was Pennzoil Platinum 5w30.

 

[spk2000]

I also noted that when I changed from Mobil 1 5w30 to their High mileage blend that was 10W40 my fuel economy increased tremendously. It went from 24 mpg to 28. This was consistent and stayed that way until I sold the car. It was a 98 mercury sable with the duratec engine. I sold it with 240,000 miles on it and it still ran good but the body was deteriorating and showing wear.

 

[Oil Changer]

With the brutally cold winter we had, I was idling as long as 30 minutes before driving off. Now it's get in, strap in, and go. Recently, I've had overnight lows in the 20's but it's been just above freezing when I leave. I was expecting higher pressures, sluggishness, and a drop in MPG. I'm not seeing any of that with the 0W-40.

 

[buster]

I put Mobil 1 0w40 in my 03 Foreter and it's the best oil I've used yet in terms of keeping the engine quiet. It runs great on this grade.

 

[demarpaint]

Originally Posted By: Quattro Pete
Originally Posted By: Oil Changer
The only meaningful change made besides the oil is that I'm idling less in the warmer temperatures.

That right there explains your change in MPG.


Big time, and the rise in temps.

 

[tig1]

Mobil 1 0w30 would be my choice for year round service.

 

[JOD]

Originally Posted By: Merkava_4
Originally Posted By: Quattro Pete
Originally Posted By: Oil Changer
2. Fuel economy went UP from 13.5 MPG to 16.6 MPG.

Sorry, but that is just not happening as a result of switching from 5w30 to 0w-40.


Why not ? Maybe the 40 weight is lubricating better thus reducing friction. In the used oil analysis section, those Chevy truck V8's always have high wear numbers with 5w30. On 40 weights, the numbers are always way lower.


Because the laws of thermodynamics aren't suspended in Bitog-land...

Sorry, but thicker oil is almost always going to result in a small (read "difficult or impossible to measure") decrease in FE. I'm not saying the OP didn't observe a 20% increase in fuel economy, just that oil grade had nothing to do with it.

Originally Posted By: Oil Changer

3. No loss of power, strange noises or other maladies I read here on BITOG that might happen.



Where did you read that going up one grade would cause all of the maladies? Because I've never actually read that on this site.

 

[CATERHAM]

Originally Posted By: Oil Changer


1. Oil pressure is instantaneous even with the few just above freezing morning temperatures I've had here. I expected higher pressure readings both cold and hot but the gauge reads the same.

2. Fuel economy went UP from 13.5 MPG to 16.6 MPG. My station could have switched from winter blend to summer but have not confirmed nor do I think the attendant would even know.


Compared to a 10w30 on start-up Mobil 1 0W-40 can be even lighter at temp's as high as room temperature. But make no mistake, compared to a 5w30 like Mobil 1 it will be heavier at all temp's.
And unless your engine is worn, your OP gauge will tell you that, you will have better overall lubrication running the 5w30.
For the same reasons, Mobil 1 5w30 is a better lubricate choice in the 638 HP Corvette ZR-1 than Mobil 1 0W-40.

 

[OVERKILL]

Originally Posted By: CATERHAM
you will have better overall lubrication running the 5w30


Can you elaborate on this? I can't see how this would be the case. Perhaps he'd had 0.001% better fuel economy, but I don't think that a 5w30 is going to provide "better" lubrication than a 0w-40, particularly not Mobil 1 0w-40, which has more manufacturer certs and approvals than any other oil they make.

Originally Posted By: CATERHAM
For the same reasons, Mobil 1 5w30 is a better lubricate choice in the 638 HP Corvette ZR-1 than Mobil 1 0W-40.


For daily driver duty perhaps one could argue that it is a more appropriate choice for the oil temps encountered. For track use GM runs Mobil 1 0w-40 in their own Corvette Program cars.

 

[Oil Changer]

I don't pretend to be a Corvette expert but doesn't that vehicle have aluminum block/heads, dry sump, oil cooler, and engine cooling that could be described as heavy duty?

Mobil 1 recommends 0W-40 for the same car in the UK
Mobil 1 UK Corvette ZR-1




Originally Posted By: CATERHAM
[/quote]Compared to a 10w30 on start-up Mobil 1 0W-40 can be even lighter at temp's as high as room temperature. But make no mistake, compared to a 5w30 like Mobil 1 it will be heavier at all temp's.
And unless your engine is worn, your OP gauge will tell you that, you will have better overall lubrication running the 5w30.
For the same reasons, Mobil 1 5w30 is a better lubricate choice in the 638 HP Corvette ZR-1 than Mobil 1 0W-40.