Synthetics have a lot of detergents in them and may clean it so well, that it will open up some leaks.
Consumer Reports in 96 did a test of motor oils on a fleet of NYC taxis. All vehciles were identical and were tested after 100,000 miles. Engineers tore them down and performed all kinds of measurements and compiled data on each. Each vehicle used a different oil for the duration. Exotic synthetics, additives, treatments, cheap store brand etc. There were NO differences in any of the vehciles in regards to wear, maintenance, etc.
Synthetics will work at higher temps, but I'm not sure many motors reach them.
I have run the chaepest oil in all my vehicles and change it out regularly at 5000 kms (3000 miles). I have done this on my Cobra over the past 100000 miles (obviously this car is not driven lightly) and it is still pushing near- new compression. Even if I had blown my motor at this time AND it was caused by the cheap oil (that incidentally meets API specs), I could have replaced 2 motors with the money I would have spent on synth.
That is strictly my opinion. Others will no doubt disagree.
It's not too late. Due to the higher detergency of the synthetic oil, you'll want to either use an engine flush product before you use the new oil (new filter, add flush, run the engine, shut off, drain the oil & flush product, another new filter), or you should change to the synthetic oil and change the filter at 1,000 miles, 3,000 mi., and your next regular change.
Synthetic oils are even better. Worth the money?...that's the discussion. Syn oil is certainly good for the full oil change interval shown in your owner's manual. Some brands recommend change intervals as long as 35,000 miles or one year. Mobil 1 recommends the standard interval. Syn oils will protect your engine better in very cold or very hot situations, and if you have a catastrophic loss of coolant or oil might limit engine damage. Syn oils run cooler because they transfer heat better and don't generate as much heat due to lower fluid friction. Expect to gain maybe 1/2 mpg of fuel mileage.
Should you change to syn oil? That's up to you.
Synthetic ATF and gear oil are highly recommended. They run cooler.
I have used AMSOIL in gas & diesel engines.
My PSD with 33,000 + miles has had only one oil change and every 10,000 miles I have the oil tested so far no problems. My wife's 97 with 3.1 V 6 engine has had 5 oil changes in that period.
The last 3 years the oil has been tested for any problems No excess wear. This car has several cold starts and short trips today 5 3/4 years since new with 65,000 miles.
You will find that with fuel mileage increases and your oil change cost is "0" or much less.
Dealer cost or Perfered customer cost for
5W-30 or 10W-30 XL 7500 oil is $4.15 per quart good for 6 months or 7,500 miles. email me if you would like any other cost information
Oil does not really wear out, it just gets dirty. While synthetic lube is more "fluid" and has less fluidic resistance, it still gets dirty...
Cleaning your engine inside is the best prevention you can obtain. With todays high detergent oils, you don't need to worry about knocking off some big chunk of crud, like the old time farmers did in their 40 or 50W non-detergent oils used in tractors.
Think of a coffee pot for a second, with daily use, brown baked on oils dirty the pot... fresh coffee alone does not clean the pot, just gets it dirty again.
Your engine does the same thing, and believe it or not, higher octane fuel creates more deposit build up in your heads and upper cylinder chamber, catalyitic converter, emmisions systems, and so on.
So frequently clean your fuel system during use, and clean your engine internals with every oil change.
Octane is a burn inhibitor not a power booster.
*This Message was edited on 11-Jun-02 12:38 AM by bentrider38*
43' Travel Supreme w/TrailAir pin box
International 9400 class #8 semi (1 axle removed)
Kyocera/Verizon cell phone and Toshiba laptop to connect to internet
Full time on 2nd year
Many of the contaminants in oil are from the breakdown of the components of the oil. Some oils are formulated to breakdown at a slower rate. The lab tests tell the story. Here's info on how modern conventional oils with the new API service category SL label are being made for a longer life. This is published by 76, a Phillips brand, but applies to all brands of oil: http://www.tosco.com/internet_pub/repository/lubes/44_tn3_4.pdf
Here is a good article about "oil doesn't wear out, it just gets dirty". This is on the GM ability site.
You may have to copy and paste to your browser as I don't have the ability to offer it as a link.
Recyclers and the U.S. Military have proven that oil does not break down. It does get contaminated with the natural byproducts of combustion (acid,condensation)and those byproducts cause the damage to your engine, that fills your oil with gunk like sludge, rust, carbon, metal from your engine, and so on.
The only way to insure your not running 1k or so pounds of continual grit and corrosive chemicals through your engine, and remove water, is to change your oil!
Now if you want to dump spendy oil at each change, that is up to you. The dirt in the oil is your enemy, not the brand you choose or choose not.
try a "google search" on the phrase "oil doesn't wear out" to investigate this further if you desire.
*This Message was edited on 12-Jun-02 12:07 AM by bentrider38*
*This Message was edited on 12-Jun-02 12:23 AM by bentrider38*
The "additive packages" that come with your oils do vary. The additive's do wear out or are used up with use, but it is not the oil itself that is worn out.
The use of high friction modifiers in your engine oil, can "fool" the computers in newer rigs into calculating all is well. Keep in mind that if you use high friction modifiers (dura lube, ER...)still change your oil by the mile, not the service engine light.