Synthetic oil

[Ophidia]

Anyone have the scoop on this? I commute 110 miles a day for work, and was wondering... does this really extend the time between oil changes? I know that it is better in the winter 'cuz it doesn't thicken up like organic and makes for easier starting, but does it really extend mileage betwixt changes?
Thx
Chris

[Impaler]

I say use it. It breaks down more slowly than regular oils at high temperature. Example, when I was doing hot shot work in my '94 Chevy truck, I was driving b/t 350-400 miles every day. This translated into oil changes every other week. When I switched to a synthetic 40 weight, not the multi viscosity10w40, I was able to double my mileage before it really started turning color(9000-10000 miles). I noticed improved fuel mileage, better pickup from any speed, and overall better looking oil at change time.

JME
Dan

[hartman]

Well, I use it on my 1987 Audi 4000cs Q and I don't burn anything between changes. Also it works great with diesel cars. I use only Castrol Syntec GTX 5-50, IMO the best one. And it did raise my gas mileage a few MPG, but I think the newer the car the left affect it will have.

Hartman

[dgin]

Switching to synthetic oil in an engine that is pretty well worn could have some issues though. If your engine burns oil, synthetic will burn at a faster rate. If your engine leaks oil, synthetic will leak slightly more. I believe this is due to the better flow characteristics of synthetic. Increased horsepower, MPG, etc. are some of the advantages. I would stick to a multi-viscosity oil rather than a single weight though.

[nucleuscracker]

i run all our cars on mobil 1. I drive about 3500 month for work (sales) and changing oil every month would suck let alone cost a bundle.

But the important thing is that you cannot switch a car that has been running on regular oil for some time now to synthetic without the risk of leaks etc.......

[hartman]

One thing to remember synthetic oil is rated to last 15K miles. But I never leave it in for that time. I always change the oil at 12K, but every 3K I change the filter and top off the oil. This is very important, while the oil can last a long time the filter cannot. Keeping the oil clear is very important. Filter remove dirt and water which cause lots of damage.

Add I never had a problem going from normal oil right to synthetic.

Hartman

[Ophidia]

I've run synthetic in this car before, with no consumption problems. I let it go about 10k, which is where it started to consume a little bit and it discolored a bit. I plan on going maybe 4500 -6000 on this change, and see how it goes. As my car started consuming the oil at 10k, that was obviously too long.
I was just wondering what rule people were adhering to.
Changing the filter every 3 k is a good idea-- I will do that.
It's also somethign to do with that extra 1/2 quart left over in the jug :)
Thanks for the info guys
Chris

[DgenR8]

One more thing to add...
Before using synthetic oil in a car that has been using regular oil, be sure to remove as much oil as possible from the engine. I have been told that mixing conventional oil and synthetic oil will cause the oil to gell up into a solid sticky mess. Not good for lubrication!
I have not actually seen this with my own eyes, but the info comes from a trusted source.
Maybe I'll pick up a $5.00 quart of mobil one and mix it with some good old 10-40 to see if it's true.

[hartman]

Well, I never had any issues with going from normal to syntec and back and forth. I never mixed it during oil i.e. using them at the same time. Normal oil change will get most of the oil out.

Here is my experience
Audi4000cs Q 1997 running syntec in it since 1993 and every once in a while when I could not get it I switched back to 10-40 normal and never had a problem. This car is still on the road today at 197K. Granted I don’t think the syntec is the only reason since I’m a maintaince freak J

2 M Benz 300TD for many years with syntec no problem both cars lived to 300K one even hit 375K before we just retired them.

I would never mix then in a single oil change since normal oil IMO cannot handle 12K before change.

Hartman