How long before oil change with syn?

[Rebel3190]

I just put Mobil1 synthetic oil in my truck and was wondering how long you are going in between oil changes with syn, on conventional I was goin 5,000 miles between.

[CaptTrevStarr]

ive always done the 3000 mile rule with conventional and 5000miles on synthetic...i believe the new syns. could go as far as 7500...but NOT positive....im still running con in my truck...but running syn in my fully built dsm..

Trevor

[ff_jeff]

I always go by the condition of the oil. I check it about twice a week. When it gets dark and looks like it could use a change... then I change it. Usually it lasts about 2-3 months. I hardly drive the 3k miles. But when I used to, the oil would usually last about 3500 miles or so. I use Mobile, or GTX.

[CaptTrevStarr]

gtx in my truck......dsm loves the mobile 1

trevor

[GMCwantsLS1]

I run it till it gets dirty. About 8-10K or so. Sometimes since I don't drive it much once a year.

[6.0vortecchevy]

Ive always wondered why people run syn. The only thing its good for is really extreme temp witch your truck will never see. so i dont see the point in running syn. Im wondering dont attack.

[567234ta]

Ive always wondered why people run syn. The only thing its good for is really extreme temp witch your truck will never see. so i dont see the point in running syn. Im wondering dont attack.

never is a short time, it was 4°f here the other day, and I've had a line blow off before and lost most of my oil. Thank God i run full syn.

[mercuno]

I ran mobil 1 full syn changing it every 8k for 160k and no probs

[ff_jeff]

Ive always wondered why people run syn. The only thing its good for is really extreme temp witch your truck will never see. so i dont see the point in running syn. Im wondering dont attack.

Well, if for no other reason... buy syn because its not crude. Its made in a lab, not pumped out of the desert, or ocean.

wiki
Advantages

The technical advantages of synthetic motor oils include:[citation needed]

* Measurably better low and high temperature viscosity performance
* Better chemical & shear stability
* Decreased evaporative loss
* Resistance to oxidation, thermal breakdown and oil sludge problems
* Extended drain intervals with the environmental benefit of less oil waste.
* Improved fuel economy in certain engine configurations.
* Better lubrication on cold starts
* Longer lasting engine life

[edit] Disadvantages

The disadvantages of synthetic motor oils include

* The lower friction may make them unsuitable for break-in (i.e. the initial run-in period of the vehicle) where friction is desirable to cause wear. Improved engine part machining has made break-in less critical than it once was, though. Many modern cars now come with synthetic oil as a factory fill.
* Potential decomposition problems in certain chemical environments (industrial use dominantly)
* Potential stress cracking of plastic components like POM (polyoxymethylene) in the presence of PAOs (polyalphaolefins).
* Synthetics do not hold lead in suspension as well as mineral oil, thus caution is advised when the engine is run on leaded fuel.[citation needed] As an example, leaded fuel is still commonly used in aviation (avgas).[12]
* In July 1996, Consumer Reports published the results of a two year motor oil test involving a fleet of 75 New York taxi cabs and found no noticeable advantage of synthetic oil over regular oil.[13] In their article, they noted that "Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service — stop-and-go city driving." According to their study, synthetic oil is "worth considering for extreme driving conditions: high ambient temperatures and high engine load, or very cold temperatures." [14]
* Synthetic oils are not recommended in automotive rotary engines.[15]

[txarkitekt]

I just let my PCM tell me when to change it.

The PCM monitors your driving style and how much the motor is worked. I have seen as low a 2700 miles (when driving hard and towing) and up to 5700 miles when it is mostly easy, hwy miles. And if the oil level goes low, the PCM will light up the Message Center on your dash letting you know.

I can also predict when to change the oil (before the PCM alerts me) by my truck's mpgs. My truck tends to start getting slightly worse mpgs when it is oil change time.