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Eric
04-08-2007, 08:04 AM
On the subject of synthetics:

I just finished changing the gear lube in my pick-up (transmission, transfer case, front diff, rear diff) with Mobil 1 synthetic ("light truck" formula). This stuff is much more expensive than standard gear oil (about $14 per bottle) but I have always believed the cost well worth it for the added protection and noticeably improved operating characteristics. (For example, the transmission's gears engage more smoothly, esp. when it's very cold outside; and there is virtually no "gear whine" or driveline noise). I do the driveline every 30,000 miles - and the engine oil every 4,000 miles.

My Nissan is almost ten years old now - and has more than 100k on the clock. But it honestly runs and drives no differently now than it did when it was new. I attribute this to my fastidious care as much as to Nissan's excellent design.

Another thing I've noticed about synthetics, as far as gear lube goes, anyhow, is that upon disassembly of a transmission (or axle) I have found the internal casings and parts to be virtualy free of sludge.

I would not use anything else in a vehicle I cared about - or intended to keep for any length of time!

DonTom
04-08-2007, 09:48 AM
"I would not use anything else in a vehicle I cared about - or intended to keep for any length of time! "

I will still wait for my owner's manual to say that there is at least a small advantage to using synthetic oils.

BTW, I did use synthetic in the rear of my Jeep, because the manual says to, but only if the vehicle is used for towing. Since once in a great while I use it to tow, I did use the synthetic in the rear differential ONLY.

I have never used synthetic oils in any engine.

-Don-

mrblanche
04-09-2007, 10:30 PM
I will still wait for my owner's manual to say that there is at least a small advantage to using synthetic oils.
-Don-[/color]


How about this? My big truck recommends synthetics in the transmission and differentials. The stuff that comes from the factory is guaranteed for 500,000 miles, and the replacement is good for 350,000 miles. However, if you switch to non-synthetic lubricants, you have to switch to a 100,000 mile change schedule to stay in warranty.

DonTom
04-10-2007, 06:40 AM
"My big truck recommends synthetics in the transmission and differentials."

In such a case, I would use it too, just as I did in my Jeep's rear differential.

But when the owner's manual goes out of the way to say "change synthetic oil just as often as normal oil", why bother with synthetics?

-Don-

Eric
04-10-2007, 08:11 AM
"My big truck recommends synthetics in the transmission and differentials."

In such a case, I would use it too, just as I did in my Jeep's rear differential.

But when the owner's manual goes out of the way to say "change synthetic oil just as often as normal oil", why bother with synthetics?

-Don-



It's not just the different changeout intervals; it's the superior protection offered by synthetics. I use them for the same reasons Mike does - to give my machinery the added measure of protection, which saves wear and tear, increases parts longevity - and thus, saves me money in the long haul.

And in any kind of hard use/abuse situation, synthetics are mandatory....

DonTom
04-10-2007, 09:34 AM
"to give my machinery the added measure of protection, which saves wear and tear, increases parts longevity"

I don't think any of that has been proved true with normal driving.

Many used to say the same type of nonsense about Slick 50. Some still do.

-Don-

Eric
04-10-2007, 09:38 AM
"to give my machinery the added measure of protection, which saves wear and tear, increases parts longevity"

I don't think any of that has been proved true with normal driving.

Many used to say the same type of nonsense about Slick 50. Some still do.

-Don-


Ah, but what is "normal" driving?

For me (and many people) ordinary use is infact considered "severe" by the manufacturer. I also drive fast (as you know), so the synthetics are a no-brainer.

Also: The vehicles run more smoothly in extreme cold and there is a slight mileage benefit as well.

mrblanche
04-10-2007, 10:28 AM
I believe the synthetics are more tolerant of contaminants, too. I had a transmission cooler leak that put a lot of water in my transmission; with regular oil, I would have really been worried. As it was, I drove it home from Louisiana before I put it in the shop, with no apparent damage.

DonTom
04-10-2007, 04:07 PM
I had a transmission cooler leak that put a lot of water in my transmission; with regular oil,

In some boats that have gear oil in the stern drive, it's not uncommon to get a leak and it filling up with water without the owner knowing for years (usually not knowing until they go to change the gear oil). Usually, there is no damage as water is said to be a fairly good lubricator when there's enough of it. And this is when the water is mixed with normal gear oil.

-Don-

mrblanche
04-10-2007, 05:07 PM
In this particular instance, I knew I had a problem when I found oil (lots of it) in my coolant top tank.

DonTom
04-12-2007, 02:48 AM
"For me (and many people) ordinary use is infact considered "severe" by the manufacturer."

Eric, you might drive "severe" according to your owner's manual, but where does YOUR OWN owner's manual says synthetics are better in YOUR vehicle than normal oils when you're driving what THEY call severe?

I know what it says on the back of a bottle of Mobile One synthetic oil (pours great at -53F! Lubricates great at more than 400f !

But not a single word about how well it works at 190 to225F (normal even for the way you drive, right?).

When was the last time you drove in -53F? Had your engine at 400F? No argument under such conditions synthetic oils would be better in perhaps ANY engine.

Usually specail products for true severe (such as racing) are not good for much else. For an example, racing air and oil filters pass more garbage than do normal filters. "Severe" at most covers the way you drive, or taxi or other commercial use but is far from the exteremes that synthetics claim to be so good with.

Like I mentioned before, I have read much on engine oils and Clinton's books have a section devoted to it. "Don't use synthetics in newer cars". Don't use in older cars. Don't use when (the list goes on & on). Well, normal oils you just use it and don't worry about much else (unless maybe if you're racing uphills in the hot desert!).

Of course if your vehicle's engine was designed only for synthetics (and I think a few are, but none that I have seen) that's a different story.

-Don-

Eric
04-12-2007, 08:23 AM
" Eric, you might drive "severe" according to your owner's manual, but where does YOUR OWN owner's manual says synthetics are better in YOUR vehicle than normal oils when you're driving what THEY call severe?"

Synthetics offer superior lubrication and protection over a much wider operating range, including extremes of temperature. The owner's manual may only mention what's "adequate" or "sufficient" - not what the best possible thing to use might be, especially in terms of extended service. Most manufacturers assume a service life of 100,000 miles or so - but I like to get 200,000 miles out of my vehicles.

"I know what it says on the back of a bottle of Mobile One synthetic oil (pours great at -53F! Lubricates great at more than 400f !

But not a single word about how well it works at 190 to225F (normal even for the way you drive, right?).

When was the last time you drove in -53F? Had your engine at 400F? No argument under such conditions synthetic oils would be better in perhaps ANY engine."

If you operated your engine at very high RPM and loads, the synthetic offers a level of protection that conventional oils simply can't equal. And it does get very cold here sometimes, too. A synthetic at 10 degrees (f) external termperature) flows much more readily at start-up than a standard oil. My engine's worth the extra $15 it costs me to use synthetics at oil changouts vs. the standard oil.

As for Chilton's ect - much of that info is very out of date. The reason for cautions about synthetics is that older engines built before synthetics were put into wide use (including OEM use) has to do with things like different expansion rates of internal seals and the potential for leaks, etc.

But with any modern engine, that's not an issue.

I agree with you that for a "normal" driver who doesn't run the car hard (like you) or drive in extreme conditions of heat/cold or pull a trailer, etc. a high-quality standard oil will be just fine.

But for me - and others who do drive hard - the extra measure of protection is worth the slightly higher cost.

mrblanche
04-12-2007, 09:33 AM
Well, here's the rub. Even such an august entity as Consumer Reports says that most oil "creeps" in viscosity. They tested a number of them, back before synthetics were common, and found that Castrol stayed in grade the best of all. But even it changed pretty significantly when exposed to temps that are not that uncommon.

You "engine temperature," by the way, is not the "coolant temperature." Depending on where the coolant sensor is, it may be quite a bit warmer than that. For example, the coolant temperature in my truck consistently runs about 175, except in slow traffic or a long pull, where it will get to 210 before the fan comes on. The oil temperature, however, is a consistent 220, except under a long pull, where it approaches 250.

That's the temp, by the way, where oil is considererd to begin to break down. Hence the new diesel oil formulations.

But SOME of the oil is always exposed to higher temperatures than that. Oil that hits the cylinder walls, oil that hits the bottoms of the pistons, even oil in oil pump is exposed to much higher temperatures, but only for a short time.

My manual allows for longer oil change intervals with synthetic, but recommends changing by actual testing, not mileage.

DonTom
04-12-2007, 03:15 PM
" You "engine temperature," by the way, is not the "coolant temperature." "

But how often does oil temperature get to 400F?

But if synthetics ofter an advantage, how come NONE of my owner's manuals say to use it?

They all seem to say the same thing:

"You may use synthetic engine oil as long as you change as often as regular oil". No where does any of them say there's any advantage to using synthetics under any conditions. Have you read yours?

-Don-

DonTom
04-12-2007, 03:22 PM
"but I like to get 200,000 miles out of my vehicles."

I usually get more than 200K and have never used any synthetic engine oil. And usually a junk the vehicle before any engine problems, such as the 1989 caddy. Engine ran great until the day I junked it (more than 200K). But it needed a new tranny every couple of years or so.

Do you think my 1983 Oldsmobile V-6 would have gotten more than 385,000 miles if I used synthetic engine oil?

-Don-

Eric
04-12-2007, 06:57 PM
"but I like to get 200,000 miles out of my vehicles."

I usually get more than 200K and have never used any synthetic engine oil. And usually a junk the vehicle before any engine problems, such as the 1989 caddy. Engine ran great until the day I junked it (more than 200K). But it needed a new tranny every couple of years or so.

Do you think my 1983 Oldsmobile V-6 would have gotten more than 385,000 miles if I used synthetic engine oil?

-Don-


Depnds (again) on how you drive!

mrblanche
04-13-2007, 01:48 AM
Have you read yours?[/color]

-Don-



I've read it for the truck. I glanced at it for the Cobalt, but I would change it before it got to an indicated oil change due, anyway. I use synthetic in the Cobalt, if for no other reason, then because it requres 5W30.

DonTom
04-13-2007, 09:14 AM
"I use synthetic in the Cobalt, if for no other reason, then because it requres 5W30."

5W30 is a common "normal" oil. I use 5W30 in my Sebring and my Saturn as that's what my owner's manuals say to use. Also, in the Biretta that I used to own. And I never used synthetic engine oil.

-Don-

Eric
04-13-2007, 09:29 AM
"I use synthetic in the Cobalt, if for no other reason, then because it requres 5W30."

5W30 is a common "normal" oil. I use 5W30 in my Sebring and my Saturn as that's what my owner's manuals say to use. Also, in the Biretta that I used to own. And I never used synthetic engine oil.

-Don-






Do you use synthetic in any of your bikes?

mrblanche
04-13-2007, 10:04 AM
5W30 is a common "normal" oil. I use 5W30 in my Sebring and my Saturn as that's what my owner's manuals say to use. Also, in the Biretta that I used to own. And I never used synthetic engine oil.

-Don-






Actually, 10W30 would be a "normal" oil. And I also use at least semi-synthetic in the F150, which reqires 5w20.

DonTom
04-13-2007, 11:49 PM
"Actually, 10W30 would be a "normal" oil. And I also use at least semi-synthetic in the F150, which reqires 5w20."

Perhaps more cars use 10W30 than any other, but 5W30 (used in my Saturn) as well as 5W20 (used in my 2002 Mustang) are very easy to find anywhere out here as "normal" nonsynthetic engine oil.

In fact, you can pick your brand (Castro, Pennzoil, etc) , because both 5W30 and 5W20 are probably available in all brands.

-Don-(South San Francisco)

Eric
04-14-2007, 08:05 AM
"Actually, 10W30 would be a "normal" oil. And I also use at least semi-synthetic in the F150, which reqires 5w20."

Perhaps more cars use 10W30 than any other, but 5W30 (used in my Saturn) as well as 5W20 (used in my 2002 Mustang) are very easy to find anywhere out here as "normal" nonsynthetic engine oil.

In fact, you can pick your brand (Castro, Pennzoil, etc) , because both 5W30 and 5W20 are probably available in all brands.

-Don-(South San Francisco)


One thing to bear in mind (in addition to your self-stated mild-mannered driving habits) is that SF is a very temperate area; you don't see winters with temps. in the single digits - or summers with high humidity and 100 degrees, etc.

In winter, especially, the use of synthetics not only provides objectively superior protection, things like the transmission, etc. I notice smoother engagement/less effort, etc. vs. using standard gear lube (which congeals into thick, molasses-like gunk when it's 5 degrees outside).

And see Mike's point in re heat. It's another reason why I use only synthetics in my air (and oil) cooled bikes, too.

mrblanche
04-14-2007, 09:57 AM
Perhaps more cars use 10W30 than any other, but 5W30 (used in my Saturn) as well as 5W20 (used in my 2002 Mustang) are very easy to find anywhere out here as "normal" nonsynthetic engine oil.

In fact, you can pick your brand (Castro, Pennzoil, etc) , because both 5W30 and 5W20 are probably available in all brands.

-Don-(South San Francisco)


You should probably check for yourself, but I understand at recently all 5W20 was changed to semi-synthetic, exactly for the reason I gave; it's being worked pretty hard in modern engines.

mrblanche
04-14-2007, 10:02 AM
And see Mike's point in re heat. It's another reason why I use only synthetics in my air (and oil) cooled bikes, too.


Oddly enough, in most bikes is the one place I might not use synthetics, until I was sure they were compatible with the clutch plates. I tried one long ago in my RD350, and it caused the clutch to slip.

Eric
04-14-2007, 10:34 AM
And see Mike's point in re heat. It's another reason why I use only synthetics in my air (and oil) cooled bikes, too.


Oddly enough, in most bikes is the one place I might not use synthetics, until I was sure they were compatible with the clutch plates. I tried one long ago in my RD350, and it caused the clutch to slip.


Well, I'm not surprised as the RD350 is an ancient machine - and its clutch (OE) was not designed for synthetics... but all modern bikes are fine with synthetics - and for most high-RPM sport bikes, it's a "must use" thing!

DonTom
04-15-2007, 12:54 AM
" you don't see winters with temps. in the single digits - or summers with high humidity and 100 degrees, etc."

I do at my NV home (except for the humidity--it's desert!). And the Sebring Owner's manual says I should use 5W30 in winter and 10W30 in summer. Nowhere does it say there's an advantage to using synthetics at any time of year or in any conditions.

-Don-

Eric
04-15-2007, 08:19 AM
" you don't see winters with temps. in the single digits - or summers with high humidity and 100 degrees, etc."

I do at my NV home (except for the humidity--it's desert!). And the Sebring Owner's manual says I should use 5W30 in winter and 10W30 in summer. Nowhere does it say there's an advantage to using synthetics at any time of year or in any conditions.

-Don-


The fact that your owner's manual doesn't say anything is hardly "proof" that there's no advantage to using synthetics. The objectively superior cold flow characteristics of synthetics mean lower friction at start-up and more rapid pressurization, for one thing. Not my opinion - facts.

DonTom
04-15-2007, 08:36 AM
"The objectively superior cold flow characteristics of synthetics mean lower friction at start-up"

That was one of the reasons why it should not be used in newer cars. Wasn't good for breaking in, except for in the few cars designed for it.

-Don-

Eric
04-15-2007, 08:42 AM
"The objectively superior cold flow characteristics of synthetics mean lower friction at start-up"

That was one of the reasons why it should not be used in newer cars. Wasn't good for breaking in, except for in the few cars designed for it.

-Don-



Depends!

With some new cars, "break in" is minimal - and not only are synthetics ok, they are sometimes used by the factory - as in the case of the cars I mentioned before...

DonTom
04-16-2007, 07:48 AM
"Do you use synthetic in any of your bikes?"

No, never have.

-Don-