Oli change -- which is better?

AFAIK the BMW display also takes into account driving style. It counts one km as two when the engine is cold, as one and a half when it's warm and as two when you exceed some engine rpm.

Still the ML counting backwards is pretty impressive. Anyone with an explanation?

But I doubt that most owners would fiddle with a tool or an improvised lead.

I own a battery powered Norelco (Phillips) electric shaver. It has a "shave counter" which learns how often one shaves, and estimates the number of shaves left. It wasn't always that accurate, but it was a gee whiz piece of electronics. I have a later model which counts down the number of minutes. It's likely not that accurate, since the battery capacity will inevitably go down, but it always reads 64 minutes on a full charge.

This sort of count down mechanism is what I had in mind. If the owner wishes to perform maintenance at greater intervals, it is possible.

Which brings up another point. In the US, BMW and Mercedes-Benz advertise no-cost scheduled maintenance for the warranty period. I'm not sure how they handle oil changes given the flexible service periods; I would guess they will only change it when the computer says to. If the owner wants to be more conservative, I'm not sure if an arrangement can be made with a dealer to do every other oil change.

Which reminds me of a former poster who was a fuel and lube chemist at Exxon (Edward Kollin - are you still out there?). I read his bio, which said he headed Exxon's engine lab, as well as developed fuel and oil additives.

The one thing that stuck out was an assertion that in his experience, some of the better oils have become unsuitable in 1500 miles, while lower quality oils have gone strong at 10,000 miles. I guess it's mostly a matter of conditions.

I'm willing to bet his new Cavalier's owner's manual says to change at

7500 miles for normal and 3000 miles for severe service. Those are backwards. Severe service is what most of us drive and normal is for very few people. Then you have the oil change companies that say every 3000 miles. Then you have diesel semi truck engines that go 15,000 to 20,000 between drains. So somewhere in the middle there has to be a happy medium.

I drive 5000-6000 miles every month and work for a courier service, driving 200+ miles a day. I drive a 1995 Buick Century with the 2.2 engine and automatic. Same engine they put in 1991-2002 Cavaliers (as well as S-10 pickups and other cars) and it gets terrific mileage (25 in town, 32 highway, same as EPA estimates on window sticker). I now have 243,200 on it as of tonight. I fully expect this motor to see

300K and more with 5K changes. I let Wal-Mart do the dirty work once a month and spend $14 every time to have it done, with their cheapie filter and their bulk 10W-30 dino oil. Parents bought a new 2003 Century to replace the 1995, I'm driving it now (since 224K in November 2003).

So we've got suggestions of 1K, 3K, 5K, 7500 miles, and I haven't even covered synthetics. If you're going to use it, start now. Because later if you switch from dino to synthetic, you may find more oil leakage and such because synthetic is able to squeeze into places dino oil can't. It's a better lubricant, absolutely. But not a good idea to use in a normal to heavily worn engine. I'd guess 50,000 miles is the point of no return for synthetic IMO.

The 2.2L engine in the Cavaliers is the new Ecotec engine. I'm not sure how much different it is from the original 2.2, but if it's newer, it's probably better, and may not exhibit the head gasket problems the old 2.2 did. Mine's never been apart, never been hot, and I hope I never have that nightmare.

Alan Moore Dallas, TX

Notice - I do not respond to the above email address, change the ilema to crownvic to respond to this message outside of this thread.

The issue isn't so much the filtration ability, as the articles on the oil filters on the Internet all state that the Fram filters meet the spec on filtration.

The issue is more this: I go and buy a Purolator double filter and it costs $5.99, next to it is a Fram double filter that costs $5.99. Inside the Purolator is steel end caps and a good drainback valve. Inside the Fram is cardboard end caps and a cheap drainback valve.

Now maybe both filters will last 3K without disintegrating, but why should I buy the one that uses cheaper internal parts when I can get one with better internal parts for the same money?

Ted

"Jan Kalin" wrote >

The explanation must be that there is either an optical or electrical sensor monitoring oil condition which overrides the mileage and time counter either way to an extent. Either that or there is a chemical lab inside the engine with a technician who decides what needs to be done and when :-)

Huw

If the discussion is about oil filters: There aren't the rules & regs that apply to filters like there are with oil. In oil, you've got SAE, API and ACEA (Europe). Therefore it's interesting to see the testing machines that show how much most filters let through and how little they acutually hold before they are totally usless. On the topic of oil: the better the oil, the less work the filter has to do. If it's additives you want to use, these will load up the filter and then you've nothing, no filtering no lubrication.

In our '04 RAV we've just had it in at 6300 kms. for its first oil change we were recommended by the dealer's service guy to do it sooner than the Owner's Manual suggestion of 8,000 kms. The counter guy wants us to bring it in at 14,300 kms. but I'm thinking it will make it to

16,000 kms. no problem with Amsoil's XL-7500. I'm curious about what the "Serivice Required" indicator light will do as we approach the 14,300 or 16,000 mark.

Here's another thing to factor into this mix: 1.) Getting a filter that holds back finner contaminants and 2.) Holding 30% more contaminants. 3.) Lasting 30% longer. All three are possible without reducing flow and even if priced a few dollars more, would such a filter not be worth it, especially if it was used with superior engine oil? RH