I hate to beat a dead horse here...but I need some advice...

I'm sure as many of you know that I sold my 93 Bonnie and bought a brand new 04 Cavy a few weeks ago. Well, it'* almost at 3,000 miles and time for the first oil change.

I've never used synthetic oils, but am considering it. I've heard that it'* best to start using them when the engine is new (is that true?). Mobil1 seems to be the concensus around here for synthetic oil...but what is the oil change interval that you guys use? 7,500 makes me real nervous! But it'* too expensive to change out every 3,000 miles! Any thoughts?

And what filter performs best with synthetic oils?

And a general question...is the life expenctancy of the engine increased THAT much if I use synthetic every 5,000 miles vs. the typical Castrol that I run every 2,800-3,000 miles?

I run it in my 93. 2 years now. My feeling is to NOT run it on a new one until after the motor is broken in.

On SOME high mileage motors, it can be a problem. Studies have shown Mobil1 is more effective at OVER 5k when compared to dinosaur juice at 3k. Some of those studies are posted here.

Will:
I have 10K on my new Bonneville. Are you saying that it is OK to switch to synthetic at this time? Also it sounds like you are recommending that on a new car regular motor oil is preferable to synthetic. Is this correct?

The reason I ask is that I am 90% sure that I want to switch. I have never run a synthetic before in a car and cannot find a valid reason not to change over at this time. Your statement sort of validated my decision to switch at this time.

I heard you can switch to synthetic oil for your first change.

When is the motor considered "broken in"?

I've seen recomendations that say to wait until 10k to switch. However, for the first oil change in both the GTP and SSEi, which was at right about 1500mi or so for both, we used the Valvoline Dura-Blend, which is half synthetic, half dyno oil, and thats what we always have put in them since then. I switched to it in my STE on my last oil change and I'm very happy, I was using the max life stuff before then and it didn't seem to help the smoking problem (the car would POUR blue smoke out the back, but only at idle when the engine was completley warmed up...I'm pretty sure its something in the turbo), but when I switched to the durablend, the problem virtually dissapeared. It just barely smokes a little blue smoke after you let it idle for like 10 minutes, you pretty much have to be looking for the blue smoke to notice it now...before if you let it idle that long you wouldn't be able to see the car inside the smoke. However, we still change the oil in the GTP and in my STE at a little less than 3k. The SSEi usually goes 6-7500 miles between changes, but mostly because of how quickly the miles add up we just don't get a chance until its been that long.

Shawn

I use Mobile 1 on my 93. Seems ok for me.

Mobil1 Syn for me. It'* my first oil change with it. Love it so far

I switched my Olds to synthetic at 150K miles (after a complete flush). Never used oil or leaked. Prior to that, I got it changed every three months, regardless of milage.

When I got my Bonne, I had the dealer do the change before I picked it up, so it only had about 28 miles on the dino stuff (I still consider it "factory fill" and have the emblem to prove it )

I have been changing my Mobil 1 based on the oil life monitor. It seems to be calibrated to engine hours and run time, so it differentiates between city and highway driving. The most I got on one change was 8600 miles and the oil still looked like honey and was at the full mark. Basically, I pay twice as much for an oil change, but can go at least twice as long between, so it is a wash cost-wise.

Jay

I made the switch to Mobil 1 yesterday. Thanks to all for your advise.