Mobil 1 and other Synthetic Oils

Do synthetic oils make any difference or have regular oils gotten so much
better over the last 30 years that synthetics no longer offer a benefit?

 

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
90 mph). If you want your warranty intact you must change at prescribed
intervals synth or not though. Some sight some lofty brands specifying synth
oils like Porsche, some Benz etc for their 15k change intervals. It's not
just because of synth and it's NOT the only reason they're spec'd. Think of
how a Porsche is used (especially in Germany) very high sustained speeds in
varying weather. Also another reason the oil changes can be extended is the
large amounts of oil they hold. Some as many as 10 or 12 qts.
Larry

 

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.

 

What does a trip computer have to do with how an engine is used? Those
vehicled are regularly held at or near redline for very extended periods. I
fail to see the significance of a trip computer other than a convenience.
Hell my T&C has a trip computer but I still do my oil & filt at 3000-3500
miles.
Larry

 

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

 

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
--
For direct contact replace nospam with schmetterling
---

[.......]

 

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

DAS
--
For direct contact replace nospam with schmetterling
---

[........]

.....................

 

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

 

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.