0W-40 in 1970 Cadillac Eldorado

You might get away with it, but I would never do it. The only engines the call for 0w40 have micro polished crank journals. Using 0w40 could cause rapid wear, and it would be a crying shame to wipe the bearings on such a rare engine. The Rotella is *great* stuff but would probably show no benefit on such a low mileage engine. I use it exclusively on both my hi mileage vehicles. HTH Ben

So then you'd recommend a conventional 10W-40?

do you really want to take mechanical advice from a guy who purchased his education online?

do you really want to take mechanical advice from a guy who purchased his education online?

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do you really want to take mechanical advice from a guy who purchased his education online?

do you really want to take mechanical advice from a guy who purchased his education online?

To sell OIL?

D> So then you'd recommend a conventional 10W-40?

I suggested Havoline 5 w 40 in the winter, cheaper and does as good a job with your engine is oil costing 10 times as much. This all depends on how much you drive the car and many other factors. Is it garaged? With an engine of that vintage you just won't get anything out of synthetics that make it worthwhile. Just stay away from Pennsylvania oils. Anything paraphin based. A good grade major oil company oil, Texaco, Shell, Union 76, Phillips are ALL good. You can get that stuff dirt cheap in most parts store or Wal Mart. Just NEVER buy a house brand. Any MAJOR oil company's good grade oils. Frankly a 10 weight in winter and 30 weight in summer is even better.

The Rotella isn't like a conventional 10W-40... it's made with petroleum base stock, but it has a lot more ZDDP in it than a modern conventional oil does. This is a big deal for the cam arrangements in many older engines.

--scott

Yes I would. And 20/50 for the summer. HTH, Ben

Actually, the 1970 500 has virtually no smog equipment beyond the pcv, which doesnt hurt a thing.

400 HP and 515 ft/lbs with a perfectly smooth 700 rpm idle and 15 mpg is crazy good. I've swapped them into a 84 camero and a 71 chevy truck. Even better is a smogger 500 from 73-75 with closed chamber heads from a 60's 425. 13.5-1 compression with good flow, 450 hp. Cant run pump gas though... 71 500 had 400 hp, 72 500 had less than 300. To comply with federal smog laws (not nader...) the compression went from 11-1 to 8-1 and rthe cam was changed drastically. But I digress... HTH, Ben

Actually, the 1970 500 has virtually no smog equipment beyond the pcv, which doesnt hurt a thing.

400 HP and 515 ft/lbs with a perfectly smooth 700 rpm idle and 15 mpg is crazy good. I've swapped them into a 84 camero and a 71 chevy truck. Even better is a smogger 500 from 73-75 with closed chamber heads from a 60's 425. 13.5-1 compression with good flow, 450 hp. Cant run pump gas though... =================

I am fairly sure it had a smog pump on it, and a bunch of other stuff. My

74 sure did.

So my decision at the moment is to change to a regular, nothing-special-about-it, 10W-40 motor oil in the Spring. I'll use a K&N oil filter, though I've never found them any better or worse than any other oil filters. Mobil-1 doesn't make the filter for this car anymore.

Any suggestions for a good oil filter for this car while we're at it? Anyone disagree with my ultimate conclusion about oil grade?

Someone suggested 20W-50 for the Summer. Dealership told me that'd be a bit on the thick side. Moving to South Florida later in the year, so is that an even better incentive to go to 20W-50?

Take a look at the Purolator ONE filter. You won't need 20 w 50 unless you plan on either racing the Eldo or doing LOTS of highway driving. Conventional oil, Texaco Havoline is about as good as it gets. Shell isn't bad. Havoline is dirt cheap in most auto parts stores, Wal Mart etc. You won't find any conventional oil that's better. There are several just as good. Shell, Union etc. The fact is you can get Havoline anywhere.

only way to really answer is to watch your oil pressure gauge. if it's in spec don't worry about it. Purolator, Wix, Luber-Finer all make good filters. If you want to "drive it forever" check out the Canton Mecca replaceable element filters. Not cheap but supposedly the best full flow filters you can buy. Just use a good quality oil with a decent amount of ZDDP.

nate

How old is "old" oil? I have an unused/unopened quart bottle of Mobil Drive Clean 10W-30 that I'd like to find a use for. They haven't made Drive Clean in a few years. Generally how long is a bottle of conventional oil good for? I understand synthetic is good for quite a few years.

One quart isn't going to do for your engine. Use it in a lubricating can for bicycle chains chain saws etc. Never MIX oils in a good engine. Or give it to a friend who has an oil burner.

Yes I know. The car takes 5 quarts.

But lets say I have some oil from, e.g., 2003 still hanging around in unsealed bottles. (Mobil Drive Clean). Should I recycle it or is it still fresh enough to use in a car that requires that grade (10W-30 in this case)?

Motorcraft makes a nice 5W-50 full synthetic. Anyone have any thoughts on that for the '70 Eldorado with the 500 CI motor?