5W-30 vs. 10W30: Does it really matter?

Messages
398
Location
Chicagoland, IL USA
I just bought a new 2003 Ford Ranger FX4 Level II, which calls for 5W-30 oil in the manual and on the oil fill cap. No other oil is recommended for use, just 5W-30. From reading these forums, it seems that Mobil-1 10W-30 SSis thought to be a better built oil than 5W-30 SS. I was just wondering during the summertime what would the benefits of running a 5W-30 instead of a 10W-30 be here in the St. Louis, MO area (it does get pretty hot here). In the winter, I definitely will use 5W-30, as it should flow easier when the engine is cold. Thanks for the help! Chuck P.S. This is an AWESOME site!!!!
 
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7,775
Location
Oklahoma
I'd stick with the manufacturers suggestion. A lot of folks have stuck to the manufacturer recommendation and have had most excellent results.
 
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8,937
Location
SC
I honestly don't see any objective reason for anyone to conclude that Mobil 1 5w30 is inferior to Mobil 1 10w30. If your vehicle calls for 5w30, then I'm confident you could use Mobil 1 5w30 year round with no problems.
 
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4,844
Location
Saskatchewan
I believe there are only disadvantages to using 5W-30 in warm weather. 5W-30 starts with a thinner base stock and requires more viscosity index improvers, so it has poorer properties at high temperatures and will deteriorate more over its service life. Of course, this is less of a problem with synthetics. In cold weather 5W-30 may improve fuel economy, but there isn't a large viscosity difference between 5W-30 and 10W-30 for warm weather engine operation . 5W-30's have improved greatly since the early 80's, when they were not recommended for any temps over 10 deg. C, and no problems will result from using it with a proper oil change interval, but 10W-30 is still slightly superior if there are no cold weather requirements.
 

Patman

Staff member
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21,989
Location
Oakville, Ontario
quote:
Originally posted by rpn453: I believe there are only disadvantages to using 5W-30 in warm weather. 5W-30 starts with a thinner base stock and requires more viscosity index improvers, so it has poorer properties at high temperatures and will deteriorate more over its service life. Of course, this is less of a problem with synthetics.
This is just it, if you use synthetics, you can safely run 5w30 all year round and it won't thin out. But most cheap dino 5w30s tend to thin out very easily. Mobil 1 5w30 used to thin out very easily too, but with their latest formula it is very stable. I used to hate 5w30 oils (even synthetic) for that thinning out problem, but after seeing so many good synthetic (and Schaeffer blend) 5w30 reports now, I'm sold on 5w30. If it doesn't thin out on you, then it's still a good choice for summer use since it'll be thinner on startup than 10w30, even on a hot summer day, so it'll give you better engine wear numbers. Keep in mind, when your oil is cold and thick, your engine is wearing out, so the thinner your oil is at this crucial time, the better off your engine will be.
 
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901
Location
Northern Illinois
In my 02 Silverado 4.3 the M1 5W30 has been reported as being 14(40wt) or above in the last 3 analysis. The distance was from 5 to 7K miles and I put on a lot of highway miles. At least in this engine/place thinning is of no concern.
 
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Location
USA
dickwells, you can not get a 2002 GM C/K truck with a 4.3V6. You proably have the 4.8 V8. Easy typo to make I know I make tons of them!!!
 

Al

Messages
19,202
Location
Elizabethtown, Pa
I would go with the 10W-30 Mobil 1. Oil Analysis reports on this oil have been excellent. Mobil 10W-30 will be superior to a 5W-30 conventional oil. Probably not a real big deal-but I vote for the 10W-30 Mobil 1. Here in Pa. I have used 10W synthetics for almost 10 years in many cars. Have had no problem starting at temperaturew (no garage) at - 17 F. Just another point of view. [Cheers!]
 
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4,478
Location
Southern California
If you'll be using dinosaur juice, I'd vote for 10W-30, too. At any temperature above +30 degress F., the actual cold start viscosity differences won't be significant. The 10W-30 puts less stress on the viscosity index improver during hot driving than the 5W-30, too, as stated previously. To be fair, these are probably more "feel-good" considerations than practical, though. I doubt you'll grind your motor down to a nub any sooner if you decide on 5W-30. As others pointed out, the current crop of 5W-30 oils are quite good enough if changed regularly these days - even the dino ones.
 
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1,992
Location
Windsor,Ontario
Depends on the engine...the 4.3 is basically a small block Chev with the back two cylinders knocked off...I use 10W-30 Mobil SS in a customers 2000 Blazer in the summer and then go to the 5W-30 for the fall and winter...it gets hot around here in the summer...with traffic idling... the air on.. I think the 10W will live longer...she does alot of city driving with stop and go driving mixed in because of her job..mail delivery...so I decided to go a bit thicker in the summer...then swich back to the thinner oil when it gets cold...but I'm old fashioned on oil weights and like a thicker oil when it's 90 outside [Big Grin]
 

chucky2

Thread starter
Messages
398
Location
Chicagoland, IL USA
Thanks you all very much for your replies!!! [Smile] Lots of good advice and points here, so just let me add some comments... I will without a doubt use the Mobil-1 5W-30 SS in the colder months and the winter, as it will flow better (how much better I don't really know) and won't have to deal with the heat that the summers here can (and probably do) put out. Since I've just got the truck (it only has 150 miles on it now), I'll be running the factory fill for however long my research and everyone's advice here decides on. I'm already going to change the filter out at 500 miles, to what filter I don't know yet, but that is already decided on. The real issue I was wondering about was if it would be better in the summer months to run the Mobil-1 10W-30 SS since the temperatures would only be 50F at the very coldest (at night on a cold night), or is it better to have the Mobil-1 5W-30 SS in there during startup since it's a 5W and will get up through the engine faster? The disadvantage that the Mobil-1 5W-30 SS doesn't hold up as well as the Mobil-1 10W-30 SS, or does it? The driving I'll be doing is a pretty good mix of city and light highway (60MPH and under). Also, I'm sticking with 3,000 mile oil changes, as this is what my girlfriends Mustang GT schedule is and it's convenient to just change them both at the same time (it's going to work out that when her Mustang is due for her next oil change, my Ranger will be due for its first - good coincidence). Thanks for the ongoing advice!!!! Chuck
 
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34,054
Location
Southern NJ
quote:
The disadvantage that the Mobil-1 5W-30 SS doesn't hold up as well as the Mobil-1 10W-30 SS, or does
It depends. M1 10w-30 has shown to be phenomenal. The LS1 study going in now suggests the 5w-30 is great too. The 10w-30 probably has a slight advantage. I'd run 5w in the winter and 10w in the summer.
 
Messages
102
Location
Southern California
[/QUOTE]It depends. M1 10w-30 has shown to be phenomenal. The LS1 study going in now suggests the 5w-30 is great too. The 10w-30 probably has a slight advantage. I'd run 5w in the winter and 10w in the summer. [/QB][/QUOTE] How about just driving to a hot place like say Phoenix. Should I be concerned that the oil in my engine is 5w30 and not 10w30? Should I change it prior to driving or will I be okay? BTW, I only have 3,200 miles on my '04 Sienna and would like to wait until about 5,000 before switching to synthetic. Maybe I'm just being paranoid. It happens a lot. [Smile] [ June 05, 2003, 05:13 PM: Message edited by: kiko ]
 

chucky2

Thread starter
Messages
398
Location
Chicagoland, IL USA
buster- That's exactly what I'm leaning toward doing. I'm just wondering if the advantages of running the 10W-30 are outweighed by the 5W-30 working its way through the engine quicker? Al- I know. [Smile] But, I already know I'll be keeping the truck until it literally isn't drivable anymore, and at that point I'll probably ask someone in the family if they want it; the potential for the truck to see 200,000 miles is not out of the question. Therefore, I'll take the price hit on the protection I can expect from the oil. kiko- I am by far no expert, so I will not hazard a guess at your question. Hopefully someone hear much more knowledgable than me will give you some advice. This is the place to learn about oil related stuff though!!!! Thanks! Chuck
 
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3,031
Location
Florida
I would go with 5000 mile changes with the synthetics. I agree with Al, you are just throwing your money away if you change synthetics at 3000 miles. Synthetics can easily go past 7500 in "normal service". Stick with 5-30 year round. I would leave factory filter and oil in at least 1500 miles then change to synth. [Cool] [ June 07, 2003, 02:11 PM: Message edited by: Amkeer ]
 

chucky2

Thread starter
Messages
398
Location
Chicagoland, IL USA
Amkeer- Thanks for the feedback! Maybe I will extend the drain intervals, it's just a little hard abandoning the 3,000 mile rule after 10 years of practice. [Smile] I can't imagine how hard it must be for people who have been doing it for real long. Thanks again! [Smile] Chuck
 
Messages
508
Location
milwaukee
If you are going to change the oil at 3,000 then clearly you would want to stick with the 5w-30 all the time to get a better cold start. The advantage 10w-30 has, (if any.) won't apply at 3,000 miles. You can run any oil 3k with good results, and you plan on running a great oil 3k. If you are not going to sleep well with a 5k drain interval, then 4k sounds like a good compromise. What oil is the Mustang Gt running?
 

chucky2

Thread starter
Messages
398
Location
Chicagoland, IL USA
greencrew- Thanks for the feedback! My girlfriends has a 2002 Mustang GT, so I've been having her use Gastrol GTX 5W-20 almost exclusively (used Motorcraft maybe a couple of times, went back to Castrol after I found out it has Moly). I use a Mobil-1 filter on hers though. Most likely I'll switch her over to Mobil-1 0W-20 SS after I feel comfortable that it is a credible oil, and not just Mobil trying to corner the 20 weight synthetic market. We have pretty much the same driving distances to cover, so we'll be hitting the 3,000 mile change intervals at the same time. You think for 3,000 mile changes the 5W-30 will provide as much protection as the 10W-30? Thanks! Chuck
 
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