How much oil between changes?
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
I went 8k on my last run of syn Rotella, and there was plenty of life left in it, per Blackstone Labs. I have a strange spike in iron, and the other wear metals a scosh high, but we're hoping that's because of the turbo breaking in. 
Here's my UOA Report:
Here's my UOA Report:
Thread Starter
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Posting Guru
Joined: Jul 2004
Posts: 1,686
Likes: 0
From: East Tn
I'd like to go synthetic, But i'm afraid it will use(leak) more oil. Plus the price of synthetic is outragous. I've been using castrol full synthetic in my s10 for bout 100k miles now and it's up to about $6.50 a quart. It was about 1/2 of that when I started using it. Good thing it only uses 3.5 quarts.
Hotshot
Joined: Nov 2006
Posts: 11,288
Likes: 269
From: North of Greenville
Brandon... the issue of leaks is something of the days long gone by. I've changed to synthetic in all my vehicles over the past 25 years (73 Jeep Cherokee Wide Track, 86 Olds 98, 92 Plymouth Minimvan, 85 F150, 02 F250, 03 Excursion, etc.) and never run into that leak myth.
On the issue of cost, a lot of us are paying in the $17-$20 per GALLON price for full synthetic (Rotella-T, Schaeffers, etc.). Some of us (me included) are also running an oil bypass filtration system and getting a good 15K miles between changes with still very good oil quality test results at that endpoint. So, the true cost of going syn is not as straight forward as comparing price per quart. On top of that, my truck has a compeltely different sound to it with the syn I'm running... smoother and steadier and I also get faster/easier cold startups in winter by using 5w40.
On the issue of cost, a lot of us are paying in the $17-$20 per GALLON price for full synthetic (Rotella-T, Schaeffers, etc.). Some of us (me included) are also running an oil bypass filtration system and getting a good 15K miles between changes with still very good oil quality test results at that endpoint. So, the true cost of going syn is not as straight forward as comparing price per quart. On top of that, my truck has a compeltely different sound to it with the syn I'm running... smoother and steadier and I also get faster/easier cold startups in winter by using 5w40.
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
Syn Rotella is $19/gal. Regular is about $11 or so. Raises the cost of an OC by ~$32, but you can go about another 60% longer on the oil, or more if you're comfortable with it.
Syn causing leaks is old issue. New syns don't do that. I switched at about 65k and have no leaks 30k later.
Syn causing leaks is old issue. New syns don't do that. I switched at about 65k and have no leaks 30k later.
Hotshot
Joined: Nov 2006
Posts: 11,288
Likes: 269
From: North of Greenville
Not thinner.... that's a function of viscosity. 15w40 dino oil has the same viscosity as 15w40 synthetic. Apparently, the synthetic is simply a lower friction oil that typically maintains its lubrication properties longer than dino.
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Hotshot
Joined: Nov 2006
Posts: 11,288
Likes: 269
From: North of Greenville
Actually, the oil's viscosity gets lower as it gets hotter (40w cold, 5w hot). You see the same kind change take place when you put margerine or butter in a pan on the stove, but it's just a more exaggerated change than what takes place in our engines with motor oil. Its the better lubricity properties (meaning it takes much lower temperatures fr the oil to get more difficult to flow) which makes the difference on cold startups, as indicated by the "5w" designation, which is an indication of how easily it pours at winter conditions... not really any "thinner" in terms of protection, but I guess you might say it's thinner in terms of how easily it pours.
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
Let me rephrase -- both oils are the same vis when hot. The syn is thinner than the dino when both are cold. You can check this by putting samples of both in your freezer. Prepare to be amazed if you do... 
And the way I understand it, Pete is that the syn is like a 5-weight oil when cold. The dino is like a 15 wieght oil when cold. But both are like 40 weights when at operating temp. Therefore, the syn is thinner when both are cold -- I think you have it backwards. Both are obviously thinner when heated -- it's the cold state that's different.
And the way I understand it, Pete is that the syn is like a 5-weight oil when cold. The dino is like a 15 wieght oil when cold. But both are like 40 weights when at operating temp. Therefore, the syn is thinner when both are cold -- I think you have it backwards. Both are obviously thinner when heated -- it's the cold state that's different.
Postmaster
Joined: Jun 2006
Posts: 2,647
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From: Fulltime RVer
An oil is rated for viscosity by heating it to a "specified temperature" and then allowing it to flow out of a specifically sized hole. Its "viscosity rating" is determined by the length of time it takes to flow out of the hole. If it flows quickly it gets a low rating and it flows slowly it gets a high rating.
So the "viscosity rating" of an oil doesn't change with its operating temperature but the oil itself does thin out at ever increasing operating temperatures!
So the "viscosity rating" of an oil doesn't change with its operating temperature but the oil itself does thin out at ever increasing operating temperatures!
Lead Driver
Joined: Jun 2007
Posts: 7,760
Likes: 27
From: Hampton, Maryland.
OK . . .What does a 5W-30 do that an SAE 30 won't?
When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.
When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C). The difference is when the viscosity is tested at a much colder temperature. For example, a 5W-30 motor oil performs like a SAE 5 motor oil would perform at the cold temperature specified, but still has the SAE 30 viscosity at 210° F (100° C) which is engine operating temperature. This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.
Hotshot
Joined: Mar 2001
Posts: 13,556
Likes: 80
From: Manhattan, KS
On the subject of synthetic oil, I'm still running dino Rotella. In the last year and a half I've put only about 3500 miles on the truck. This was mainly due to the high cost of diesel last year and not needing to use the truck.
So, two questions.
1. Do you see an improvement in fuel economy on synthetic?
2. At my current miles per year it might take me more than two years to put 6000 miles on the truck. Is the synthetic going to be need to be change after a year or can I leave it in the truck for several years with low usage each year?
I like the idea of easier starting etc. with syn. in cold weather.
So, two questions.
1. Do you see an improvement in fuel economy on synthetic?
2. At my current miles per year it might take me more than two years to put 6000 miles on the truck. Is the synthetic going to be need to be change after a year or can I leave it in the truck for several years with low usage each year?
I like the idea of easier starting etc. with syn. in cold weather.