Regular vs. Synthetic

[Juniorverse]

O.K., so my barely moved (2 K in the last 10 months) '03 CTS (39,000 k) is starting to get a little long in the tooth and I was wondering when I should make the jump to synthetic oil. I think I read somewhere that higher mileage engines run better/last longer with synthetic oil. I just don't want to start $60.00 oil changes too soon. Or should I just stick with regular oil altogether?

Discuss....

Thanks!

[ABCF]

with new vehicles i start using it at about 6000 miles or at my second oil change. imo 39k is not high mileage your car is just nicely broken in.

[C&C]

You don't really need to switch to synthetic; it's your choice. I would consider switching if you live in extreme conditions. Synthetics do your engine good when it regularly has to deal with extreme cold or heat. If your engine isn't stressed by these type conditions regularly, regular dino oil will do just fine.

As for switching after break-in, that's not really a requirement; quite a few engines come factory filled with synthetic. (Synthetic isn't any more slippery than conventional oil, it just resists viscosity break down better.)

[kramcard6]

I run Synthetic in my Corvette but not in the CTS! It's a waste of money in the CTS, Like C&C said, unless your drving the PISS out of your CTS it's not worth it!

[iwa100]

As soon as I bought the car I switched over to sythetic. I can really notice the difference in the way the car drives though between regular and sythetic. Regular makes it seem sluggish as opposed to conventional oil.

[Chief_AT]

When I had a VW station wagon - years ago - I drained the fossil oil and filled with Mobil 1. About ten seconds after started the engine, I had to run to the engine and lower the idle speed setting - the engine was revving over 1k rpm. When I sold the VW, I replaced the Mobil 1 with fossil oil, and had to raise the idle speed setting so that the engine would run. That Mobil 1 definitely had an immediate effect on engine speed, and it had to be related to reduced friction.

[C&C]

Originally Posted by iwa100

As soon as I bought the car I switched over to sythetic. I can really notice the difference in the way the car drives though between regular and sythetic. Regular makes it seem sluggish as opposed to conventional oil.

Originally Posted by Chief_AT

When I had a VW station wagon - years ago - I drained the fossil oil and filled with Mobil 1. About ten seconds after started the engine, I had to run to the engine and lower the idle speed setting - the engine was revving over 1k rpm. When I sold the VW, I replaced the Mobil 1 with fossil oil, and had to raise the idle speed setting so that the engine would run. That Mobil 1 definitely had an immediate effect on engine speed, and it had to be related to reduced friction.

Unless you changed the viscosity of the oil (substantially), when switching, I'm calling B.S. on both these posts. Synthetic is no more slippery than conventional.

[nickc50310]

I hope youre not running convential in your STS.

[tommy compton]

sythetic always, it's just better.

[philly88]

I use regular in my SUV and change it often. I only use the synthetic in the CTS, which is recommended by the way in the manual. I'm in northern ontario, plenty cold up here and when its -30 its good to have that oil flowing as quick as possible.
That being said, I change the oil in my SUV EVERY 3,000 km no matter what the carputer says. In the CTS I'm waiting until I get to 20% engine oil life which I'm almost there and I get about 5,000km out of it before changing.

[CaddiLackin]

ive been running synthetic in my cts since day one. Is it better? I dont know. But our cars deserve the best. BTW, i have an 03 with 108,000+ miles. Runs like a champ, And i drive the chit out of 'er. oil charged at 20% also

[JimmyH]

Originally Posted by C&C

Unless you changed the viscosity of the oil (substantially), when switching, I'm calling B.S. on both these posts. Synthetic is no more slippery than conventional.

I ran conventional in my maxima for 180k miles, through stop and go, regular trips to 100mph, through winters extreme cold, and summers extreme heat. The engine is as strong or stronger than the day I bought it.

todays cars can go 15000 miles between oil changes I bet.

[Chief_AT]

Originally Posted by C&C

Unless you changed the viscosity of the oil (substantially), when switching, I'm calling B.S. on both these posts. Synthetic is no more slippery than conventional.

The Mobil 1 I used was either 5-30 or 10-30. Viscosity is the thickness (pourability) of the fluid, and is no indicator of the coefficient of friction. What I wrote about the VW is true, and, if there's any BS between us, it ain't on MY side!

[C&C]

Originally Posted by Chief_AT

The Mobil 1 I used was either 5-30 or 10-30. Viscosity is the thickness (pourability) of the fluid, and is no indicator of the coefficient of friction. What I wrote about the VW is true, and, if there's any BS between us, it ain't on MY side!

I guess we agree to disagree. I maintain that synthetic is not any more slippery than conventional. The advantages of synthetic are its stability at temperature extremes. If your Volkswagon, using conventional was at a 20W-50 and you switched to a synthetic 10W-30 that might explain the differences in idle speed. The high number in oil viscosity 'would infact' alter the coefficient of friction in an engine. I still stand by my statements (though I admit I should have been a little more diplomatic and refrained from the B.S. part; my apoligies for that).

[JimmyH]

sooooooo, since we are on the topic... I just bought a CTS 3.6, and the oil filler cap says mobil 1 on it. Does that not mean GM requires you to use synthetic? I think synthetic is a waste of money, but if GM requires it, I am going to use it rather than risk warranty issues.