Just to add, if it wasn't mentioned already, the engine design and age, as well as the driving style will make a huge difference. I have drained out oil at 4k miles that looked like new (porsche 944), and oil at 2k (Mustang I think) that looked like crap.

So, it is a good idea to check the oil regularly (maybe every 1k) for level and quality. If it looks black, smells burnt, or feels gritty, change it anyway regardless of mileage. That's what I've done anyway.

Eli.

P.S. Changing the oil at 3K is usually unnecessary, but a few engines require that type of frequency, so it's a safe bet for the industry.

I heard that sometimes oil can break down on the molecular level if you use it for too long, even if it doesn't go black, and that it can loose it's lubricative properties. They have companies where you can send an oil sample into the lab, and they'll test it for you (like if it's 5K miles, still golden, and you want to know if you really need to do an oil change)

I meant to tell you, those headlights your recommended made a huge difference...thanks. I just put new Sport Voloces (p6000) tires on too...improvement in handling was dramatic.

Is there a brighter headlight that can be installed in an 87 SDL and a or 94 S350 that won't cause heat related or other problems?

don't know but I bought a very inexpensive light upgrade from **************.com and was very pleased with the result.

I upgraded to halogen H4's with e-code lenses (euro cutoff) and I got some 100/90's (much higher wattage than normal) and I have had no problems so far as far as fuses or wiring goes. I did a fairly thurough write-up on them here and at sl107.com (fits any car with 5 3/4" round headlights, and they also have 7" ones I believe) but I ran out of webspace so the pics are all red x's by now.

oh yeah... I forgot to add... it's around 100 bucks total for the pair (after taxes and such).

I am surprise through out the thread that no one mentioned what the owner's manual says. For "normal driving" every 5K. For "extreme conditons" every 2500. Now with that said, pick your driving stlye and change accordingly. If you do primarily long distance driving where the oil has a chance to heat up properly, then go with every 5k. Do short trips or alot of stop and go drving, 2500. Do a combination thereof, split the difference.

This is the essential position of Click and Clack - that changing your oil every 3k is a waste of the planet's resources. Also, you sound like a great prospect for a topsider.

Not to disagree with "Click and Clack", but they didn't design or build the engines in our cars. Has many here have probably heard or read, that when MB car's reqiured frequent servicing, they lasted longer. These days with "sealed" transmissions and FSS maintenance, things have gone the other way. Now granted the owner's manuals for most of us here, do not mention synthetic oil, just specific weights/temps. So an argument could be started over intervals using dino oil vs. syn. Outside of that, the engineers say to change your oil between 2500-5000 miles based on driving conditions. Sure, the Jiffy Lubes push the 3K changes but that is sure to change because owner's manuals for today's cars (non-MB FSS) say every 7500-10,000 under ideal conditions, much sooner otherwise. My '99 VW Passat with it's 1.8 Turbo engine has 5K oil change intervals for ideal conditions. Again it's all in the driving conditions.
As far as wasting the earth's recources, just how many resources do you think go into the replacment engine/car takes when your engine/car has to be replaced prematurely?

The point is that if the oil is not degraded, changing it prematurely does nothing to extend the life of the engine. I think we're talking about normal driving conditions, rather than harsh - towing, dusty, short trips, etc. - and everything I have seen would indicate that oil today is not breaking down at 2500/5000 - more like twice that. I happen to like 5k changes but 7.5k per the factory doesn't bother me. There's a point of diminishing return for anything - there's just no evidence that taking perfectly good oil out at 3k does anything to extend the life of an engine.

Garage Queen Oil Changes
 

What do you all think about changing the oil on a garage queen like mine that only gets driven maybe 2-3000 miles in a whole year?
How often should it be changed? Should I change it w/ the changing of the seasons, or strictly by the miles?

Thanks,

Well I've always held to the 5k ish range. That said once I hit 5k whenever I get the chance I get the oil changed. That's been for all of the cars to date. I've only have the 500sl 500 miles or so.

That said to 450sl4me, the other side of the equation is time, I would never go less than 2 changes a year. The additives, not so much the oil, will breakdown once heated up and exposed to air.

That's a real problem with my main wheels, at < 2 mi / day to work it doesn't get many miles. But it still gets oils changes. ANd mufflers !!!!

Change it once a year.

I mentioned it earlier in this thread:

Gilly

The owner's manuals say every 5K or at least once a year.