can any one give me some advice on using the synthentic oil & would it be ok to switch from a synth to a castrol gtx. or from a castrol gtx to a synthentic
what are the advantages of using the synthentic other than it's about $4.00 quart more.

 

I'm a fan of synthetic although a lot of ppl will tell it is about the same, it is not, to know all the specs do a google search mineral vs. synthetic oil, it will tell you just how superior synthetic is, less viscosity gain, higher breakdown temp, etc.
I use it on my wife's suburban ( 2000 4x4 6.0L, 95K miles ) and we go by whatever the computer says as how often to change it but it is usually between 6 and 7K miles , engine is tight, we also use a high performance oil filter since intervals are longer ( mobil 1 or k&n ).
Bottom line is an extra layer of protection for your engine, do read about all the advantages once you do the google search, don't take my word for it.

 

I have a 96 Honda Accord, bought it new and everything stock, oil changed every 3K miles with regular oil(Castrol) but use Honda filter, the car has litlle over 150K when I gave it to my Daughter, it has 192+ K miles on it now and stills running strong, no oil leak, no oil consumption problem.

 

My wifes Honda gets slightly better mileage with syn, and you can go a bit longer between oil changes, but IMHO, it does not warrant the cost difference. If you are an earth person, you don't use oil if you use synthetics. I do agree that you should follow the manufacturers recommendations, changing oil regularly is just good insurance against major problems. I always change, and when our last car was in for the timing belt(at 90k), the mechanic commented on how clean the engine was inside.

 

To sum it up in a nutshell, synthetic oil retains its viscosity over a wider range of temperatures, is much less susceptable to oxidation, and, as Lou Bazooka stated, allows for a better level of protection. Dyno tests prove the use of synthetic oil will lower operating temperatures. Turbos almost require the use of synthetics, particularly on shutdown. A simple test to prove to yourself is to take a quart of any petro oil and a quart of a fully-synthetic oil....pop both of them in your freezer overnight and the next morning, open both and pour....I doubt you'd ever to back to petro oil again.

 

Just curious because it could have some impact; what make/model/yr and how many miles on the vehicle, wheelerbuffy?

Here is a partial list of vehicles that are known to be prone to sludge buildup and benefit from use of synthetics:

Audi/Volkswagen
1.8L 4 turbo 1997-2004 Audi A4, Volkswagen Passat
Chrysler/Dodge
2.7L V-6 1998-2002 Chrysler Concorde, Chrysler Sebring, Dodge Intrepid, Dodge Stratus
Lexus/Toyota
3.0L V-6 1997-2001 Lexus ES300,
Toyota Camry, Toyota Avalon, Toyota Sienna;
1999-2001 Lexus RX300,
Toyota Camry Solara;
2001 Toyota Highlander
2.2L 4 1997-2001 Toyota Camry,
1996-99 Toyota Celica,
1999-2001 Toyota Camry Solara
Saab
2.0L 4 turbo 2000-02 9-3 hatchback,
2000-03 9-3 convertible
2.3L 4 turbo 1999-2003 Saab 9-5,
1999 9-3 Viggen

 

I dont use it for only one reason cost. It is good stuff keep in mind all our gas turbine engines use it. The oil we use in our aircraft costs 38 dollars a quart and each engine has about 5 gallons.
It is not that much for automotive use but still too much for me.

 

I would just change oil and filter (use the oem not a wall mart one ) every 3-5 k

my toyota t100 has 202k runs great , no oil usage

 

to answer your question you can switch to synthetic or go back to conventional or vice versa anytime you change the oil.
as per advantages of synthetic over conventional oil dont really see any cars engines last just as long using conventional oil as they do synthetic it may be superior oil but is it needed, when the gas engine wears out at 200-300 thousand miles down the road the only real difference is how much it cost to maintain the car.

 

This is the most hotly debated topic on automotive forums. Like tow guy said, it'd be good to know what you're driving, driving habits, and oil maintenance habits.

Personally, I use regular oil with 3K oil change intervals. It's cheaper than using synthetics. Plus - without going into details - it works well in my personal situation.

They only time I insist on using synthetic for my clients (friends & family), is if they have a turbo or if they personally prefer it.

 

Seems to be personal choice when this comes up and a crystal ball would help to make the final decision.
I come from ships and the engines are about $300,000 to $400,000 each
Thats cheap for engines because they are rebuilt and just small EMD 645,s
We did not use syn.
I dont know of a ship that does.
Including the $5,000,000 ones
Syn is good for extreme application and extreme temperatures.
Oil analysis and changing is very important to the maintanance.
I put my money on mineral base oil and regular changes.
Cant switch back and forth from syn to mineral.
I forget why but if it has to be done there is a procedure to do it.
My 2 cents

 

This is a much debated topic.

The final answer?

Do whichever you want, it's your money.

If you are changing your oil _at the recommended intervals_ you are throwing money out the window using synthetic. Unless there is something particularlly unique about what or how you drive, synthetic is an unwarranted expense.

If you drive a cab or a police car, or a car with a turbo (more on that later), synthetic might be a good choice, but for everyday driving, it's overkill.

Turbos: The reason turbos sludge is because the owners of the cars with them didn't read the manual, which clearly states (in every owners manual I've seen on a car with turbo) that you should let the engine idle for 1-2 minutes BEFORE turning it off so that the turbo can cool down and not cook the oil.

Know anybody that sits in the parking lot/driveway with the engine running for 2 minutes before getting out?

Saying a car will go 200k+ miles IF you use synthetic is hogwash (my jeep has over 230k, doesn't burn or leak oil, always used dino oil).
Regular maintanence is the key, not the type of oil you use.

 

Well said, 'dragon.