5-20 oil

All the major makers.

But this is the present!

Is 5-20w now the recommended oil for the 3.3/3.8? My 1993 3.3 calls for

5-30.

-Kirk Matheson

If you live in a hot location 5W-30 might be a good choice. Mobil 1 comes in both a 5W-20 and 5W-30 selection. That's what I use and I change at the recommended extended change schedule of 7,500 miles or so.

Richard.

Somethin' in the air today that's causing confusion amongst "past", "present" and "future"?

5w20 is being recommended by lots of automakers in their North American-market vehicles for fuel economy certification reasons. The same engines in the same cars often call for 5w30 in other markets. This does not mean older vehicles should be switched to 5w20.

That is what I was trying to determine. From what I gather, 5w20 is now being recommended for newer versions of the 3.3 and 3.8, depending on the market. I will stay with 5w30 synthetic for my 1993 3.3.

Do new 3.3 and 3.8's have tighter clearances than their predecessors, or is is the 5w20 recommended only for the purpose of improving fuel economy?

-Kirk Matheson

No. Engine internal clearances haven't changed significantly in the last four decades.

Correct.

And I would also be concerned with longevity - it seems to me there's a fundamental tradeoff operating here. You can get best lubricating longevity or best fuel economy, but not both. Seems like good old 10W-30 was the recommended fill for most of those last four decades.

Ted

How much difference in mileage are we talking about?

Thicker isn't always better. Lot's of good info on 5W-20's in the forums at bobistheoilguy.com. The used oil analyses for dino 5w-20's are just as good as for synth. Better resistance to shear over 5w-30, too. I can find 5w-20 locally at Wally World, AutoZone, or O'Reilly's.

Bob

I'm about to do the first oil change for my new 300C, should I do standard or synthetic? I've used Mobil 1 for the past 30 years, does it make sense to continue using it or are modern 5W-20 oils as good or better then Mobil

1?

They aren't as good as Mobil 1.

Matt

The UOAs for SL/SM IL-4 dino 5w-20s are just as good as for synth. The owners manual says you can use synth, but you have to change it at the Sched A or B intervals to maintain your warranty, so no real savings in terms of fewer changes. Your call...

bob

This sounds reasonable. But I would say it is not working. My T&C with a 3.8 engine gets horrible mileage in city driving, under 15mpg. On the highway it does ok, about 24mpg. This is my biggest dissappointment with the T&C. Otherwise it is an excellent mini-van

----------- Alex

Not the point -- the point is to squeak another fraction of an MPG in on the Federal fuel economy and emission certification tests, NOT to offer the consumer measurably better on-road fuel mileage.

My reasons for using Mobil 1 has always been for it's cold weather starting characteristics, not for it's extended life. Mobil 1 flows at very low temperatures, it was developed to work at -30 or -40F as I recall. At -10F, which is about as cold as it gets in New England, how do modern oils behave as compared to Mobil 1? Back when Mobil 1 was developed conventional oils were sludge at those temperatures, but that was 30 years ago.

That is also the main reason I use it. However, it also is more stable at very high temperatures and this is important in many locales as well. Minivans seem to me to run very hot compared to other vehicles I own and have owned. The temp gauge has no absolute temperature numbers so I'm not sure how hot it really is, but I know when I open the hood on a hot day I can't even touch the prop rod to hold the hood open.

Matt

And way secondary to the squeezing of another fraction of an MPG is improving engine life. Not that it will necessarily lead to catastrophic failure or gross reduction in useful life, but there is bound to be incremental cost in engine life. IOW, will they do put value on engine life, when they get an opportunity to trade off a miniscule gain in MPG for slight or moderate loss in engine life, they will take it. Compare that the manufacturer's recommendations in countries with similar ambient temperatures that don't have CAFE rules are for thicker oils(we're talking similar vehicle/identical engine.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

check the threads

bob