Mobil 1 and other Synthetic Oils

"General Schvantzkoph" wrote

The main benefit of synthetics is a longer oil-change interval. For instance, BMW and Porsche specify synthetic and ~15K mile oil change intervals; about double the dino-oil intervals. They also come in very lightweight formulations, like 0W20, etc., that help high performance engines pass the cold-start emission tests yet protect at high RPM.

However, if you're a 3K oil-change aficionado, you might just as well stay with dino.

Floyd

Synth oils CAN make a difference but ususally in very extreme conditions. Very cold, very hot with sustained high speeds (very high speeds like over

Note the full story: A good synthetic will not coke when used under very hot conditions (non-water cooled turbo). It will also tend to pump faster when cold. (This characteristic is because of the uniform structure of the base synthetic oil).

But yes, conventional oil has been significantly improved over the years. Many people tend to change the oil too frequently today. But if you take short drives in cold weather the oil change period should be kept to 3,000 miles or so.

Richard.

What defines very cold?. Mobil 1 was developed for use on the Alaska pipeline where temperatures can be 20, 30 or 40 degrees below 0. What about ordinary cold weather, 0F or maybe -5F which is about as cold as it ever gets where I live in Massachusetts? Do those of you who regularly take engines apart notice any difference in wear between engines that use Mobil 1 vs those that use regular oil?

Synthetic oils are much more heat stable, as already mentioned by an earlier poster.

BTW, don't entirely agree with jdoe's comment about Autobahns in that cars have trip computers on which one may rely. I suggest same applie to frequent short cold-weather journeys. Oil-change intervals are likely to go down but I would still rely on the advice of a modern trip computer. With older cars it's different, of course.

DAS

I had a car that would not start at temperatures less than 15F if I didn't plug the block heater in first. I never had that trouble after switching to synthetic oil.

I'd really like to hear from mechanics who have seen the insides of hundreds of engines. I've used Mobil 1 for 30 years and I've never had cold weather starting problems but I have know way of knowing if the Mobil

1 was actually responsible. I also don't know if it's prolonged the life of any of my engines, no individual driver can know that. A mechanic who sees the insides of lots of engines is in a better position to tell. Does anyone know if any of the auto or oil companies ever published any studies?

Forty years or so ago, Molybdenum Disulphide additives were all the rage; do they still exist? I haven't looked, but I notice that the manuals for both our DC vehicles advise against using additives.

*Perhaps* synthetic oils are just another fad -- a money-maker for the purveyors, but of little or no practical value.

MB

On 08/25/04 10:59 am General Schvantzkoph put fingers to keyboard and launched the following message into cyberspace:

I can only relate what mechanics have said to me when discussing oil change intervals with synthetic: "I've seen engines that have followed

15K manufacturer intervals with very heavy sludge buildup at 75K miles."

FWIW, I change (synthetic) oil at 7500 miles.

Floyd

Well, I have used Mobil 1 since it came out. I change oil twice a year. Several times I have sent a sample to a testing lab and the used oil came back still in spec. I have never had a oil consumption problem or sludge buildup. I do not travel short cold trips in the winter; which would mandate more frequent changes.

Richard.

Why?

Trip computers are supposed to give you an indication of oil-change intervals that approx reflect the type of use an engine gets.

The US (or at least this newsgroup) seems full of people who insist on

3000-mile oil change whatever a manufacturer suggests. Still, it's cheaper than going to see a shrink because of the worry, even if it's environmentally less friendly.

DAS

No. Synthetic oils are much more heat-stable etc.

DAS

Synthetics definitely make a difference, but the real question is are they worth the cost? I use synthetic because the cold weather cranking ability they give is worth it to me. However, from a wear standpoint, most modern engines with modern oils will last so long that synthetic probably doesn't add a real advantage.

Matt

In addition to a 2001 T&C we have a 2000 VW 1.8 Turbo Passat. Just got a note from VW regarding a sludge problem with that engine. They provide a list of recommended brands and weights - all synthetic.

WVK

Matt Whit>

What oil were you using before switching? I never used anything lighter than 10W40 in any of my cars, and have only had cold starting problems on 2 or 3 occaisions - one was -46F in Winnipeg with 20W50 oil in a '69 Dart 6, and the other was a sustained

-20F with the old 1989 Aerostar 3 liter sitting in a blizzard with substandard spark plugs and wires. It flooded on the first start, then would not start, no matter how fast it cranked, untill the plugs were changed.

I have had block heaters in a few of my cars, but have only used them on the VERY odd occaision.

Southwestern Ontario snow belt since 1969.

In over 25 years as an active mechanic I have rebuilt and maintained a LOT of engines - and on vehicles serviced by the shops I worked in, with oil changes at 5000 mile or 3 month intervals, using quality

10w40 and 20w50 oils, I have NEVER seen a lubrication related failure.

On neglected vehicles, vehicles where oil change intervals have been unduly extended, or where cheap or too light oil was used, I've seen more than my share.

5W30 oil in early Ford 2.3 engines destryed camshafts in warm weather

- 10W40 or 20W50 totally eliminated the problem.

307 Chevy engines run on 5W30 routinely destroyed camshafts as well. Again, heavier oil virtually eliminated the problem. Yes, the camshafts were "soft" and eventually did go "flat" even with excellent maintenance, but not usually before the car had a LOT of miles on it, and up here in Ontario, the bodies had suffered a significant amount of rust damage.

If those engines had been run on Synthetic oils, the improvements would have been similar.

As for my own vehicles, I've only gotten rid of ONE with less than

100,000 miles (160,000km) on it, and have not scrapped any with less than 230,000Km. The only engine problems I have EVER had on my own cars were problems that existed when I bought them - a 1985 Chrysler Lebaron 2.6 with a spun bearing that required a rebuild before it could be driven, (Mitsoshitty engine) and and an Austin Mini 850 with 196,000 miles on it (burned a quart in 150 miles or so when I got it) and an old Rambler 230 with plugged oil galleries that had noisy valves until I added an external oiler, or manufacturer's defects (dropped and worn guides on 1988 New Yorker 3.0 (Mitsoshitty engine again) where I replaced the cyl heads at 189,000KM. Thats out of some 32 cars. Longest I owned any of them was 10 years

Oh yes - the G.M. nitrided camshafts. The nitrided layer was hard, but thin - once it wore thru, they wore like butter.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

Always 5W30. Usually Valvoline.

This car was a problem child, even when new. It's the only vehicle I've ever had trouble with. Switching to synthetic solved the problem.