GC, Amsoil, M1, or Rotella T Syn????

blsnelling · Apr 14, 2004

That is the question. I've got an Olds Aurora 4.0L V8 Northstar that recommends 10w-30 but can use 5w-30 below 20F. Oil pressure is quite low in this engine at idle, about 11psi. At 1000RPMs it's well over 20psi. The spec goes down to 5psi at idle as well as some reading at a set higher RPM, both of which I well surpass. This car is mostly highway driven about 20K miles/year. I use Wix oil filters. What oil would you recommend in this car? My options are:
1. Amsoil 10w-30
2. Amsoil 10w-40
3. M1 0w-40
4. Rotella T Synthetic 5w-40
5. GC 0w-30 (is this too thin since 5w-30 only
below 20F in owner's manual?)
6. M1 T&SUV (if it ever comes out here!)

blsnelling · Apr 14, 2004

BTW, this is a 250 HP, 4 OHC engine.

SSDude · Apr 14, 2004

GC is almost a 40weight oil and it will not shear. It is not thin at all.

Jeff in Western WA · Apr 14, 2004

M1 0W-40: readily available, will provide cold winter start protection, "should" give you the 30 wt requirement that GM wants (meets their "long life spec too" if that's worth anything?..)so you could just change twice a year...maybe the 40 wt designation will help the "hot" idle/op too..

BTW Advance Auto has coupon books in the store for $1 off per qt of any grade M1....makes it under $4...but, I'm a newbie here, so maybe you can never go wrong w/ M1 10W-30 and cruise other forums instead..

of reading about oil can labels...

..

[ April 14, 2004, 07:47 PM: Message edited by: Jeff in Western WA ]

Jeffrey Behr · Apr 14, 2004

bls, it's my ESTIMATE/educated guess that M1 0W-40 will have the most Viscosity-Index Improver in it, followed by the 5W-40s, with the 10W-30 having the least. GENERALLY*, VIIs are to be avoided if reasonably possible*. With your relatively low oil pressures, I'd go with the 10W-40. The Zeros would be my last choice.

I like Red Line oils, but Amsoil too makes great stuff.

* I don't mean they're to be avoided at all costs, just that if you can do without them, your engine's better off.

blsnelling · Apr 14, 2004

I appreciate the responses. Keep them comin'!

Amkeer · Apr 14, 2004

Its not on the list but I would use M1 10w30 or GC 0w30. What year is the vehicle?

Daily Drives:
-2003 Toyota Tacoma PreRunner XtraCab, 2.7 Liter , Mobil1 Synthetic SS 5W-30.
ODO 8350 Miles.
-1995 Toyota 4-Runner 3.0 V6, Mobil1 Synthetic SS 10W-30.
ODO 84500 Miles.
http://community.webshots.com/user/amkeer

blsnelling · Apr 14, 2004

The Aurora is a '97. GC is #5 in my list.

Amkeer · Apr 14, 2004

Ya but the m1 10w30 isn't.

Whats the mileage? What have you been using for oil?

[ April 14, 2004, 10:55 PM: Message edited by: Amkeer ]

Pablo · Apr 14, 2004

I would AutoRx it and run the new Amsoil 5W-40. In the summer 15W-40 may be awful tempting.....

TOMBUCK · Apr 14, 2004

I would use Amsoil 5W-40 with their FILTER. Why, Because in my book their oil and filters work very well.

blsnelling · Apr 14, 2004

I just finished the AutoRx treatment about 5K miles ago and have had Amsoil 10w-40 in it since then. It used the Amsoil like it never did before on Castrol Blend 10w-30. It also now has the dreaded case halve seepage, which was never apparent before. I'm afraid I've cleaned out some stuff I wish I hadn't. Anyway, since this engine is a known oil consumer, I don't want to use M1 10w-30. It's too prone to burning off. I have been tempted to use either M1 or Amsoil 5w-40. That's also why I listed the Rotella. I was afraid there might be too many VIIs in them with the ring pack sticking problem on this engine. Now can you see why I'm in a quandry as to what oil to use?

ekpolk · Apr 14, 2004

quote:

Originally posted by blsnelling:
I just finished the AutoRx treatment about 5K miles ago and have had Amsoil 10w-40 in it since then. It used the Amsoil like it never did before on Castrol Blend 10w-30. It also now has the dreaded case halve seepage, which was never apparent before. I'm afraid I've cleaned out some stuff I wish I hadn't. Anyway, since this engine is a known oil consumer, I don't want to use M1 10w-30. It's too prone to burning off. I have been tempted to use either M1 or Amsoil 5w-40. That's also why I listed the Rotella. I was afraid there might be too many VIIs in them with the ring pack sticking problem on this engine. Now can you see why I'm in a quandry as to what oil to use?

Just a thought about the seepage. I'd say don't do anything hasty about it. If it is a sludge-washed-off-dried-seals problem, give the fresh oil a reasonable time to "retreat" the seals.

Concerning the VIIs: Yeah, they're present in wide range syns, but in much smaller quantities than in a multi-vis dino, just because of the inherent nature of syn base stock.

Last, although it may be an engine-particular thing, I've never had a burnoff problem with either 5w-30 or 10w-30 M-1. I've used M-1 since the mid-80s and none of the formulations over those years have misbehaved on me, and I drive in typically very hot climates. I would, of course, look to Northstar users for more precise info on how that engine interacts with its oil.

blsnelling · Apr 14, 2004

My experience with M1 has been the opposite. The vehicle either began using oil where it had used none before, and in another case doubled it's consumption. I used the M1 for many thousands of miles with the same results.

haley10 · Apr 14, 2004

We have a 95 Cadillac STS with the Northstar. It seems they all leaked early on, because of the slit-block design. Our GM dealer does a lot of these repairs. They seem to leak with any oil.

I don't run syn in this one for this reason. It also consumes oil.

Whatever you chose, I wouldn't blame the oil for leaks and maybe not on some moderate consumption.

Sounds like a typical Northstar type leak, not anything you actually caused.

blsnelling · Apr 14, 2004

What oil are you using? What synthetic would you recommend? I'm only seeping at this point and consupmtion is still not that high that I won't use synthetic.

VeeDubb · Apr 15, 2004

I dunno about GC. My wife's volvo is consuming it at such a high rate, I may not need to change the oil anymore because it gets fresh top off oil every week! Okay, slight exaggeration.

Seriously, it was consuming 1 qt every 5k with Mobil 1 0w-40 and GC has already exceeded that at 4k miles. With Valvoline Synpower 10w-30, it was only consuming 1/2 quart every 5k. I'd give it a shot.

ekpolk · Apr 15, 2004

quote:

Originally posted by blsnelling:
My experience with M1 has been the opposite. The vehicle either began using oil where it had used none before, and in another case doubled it's consumption. I used the M1 for many thousands of miles with the same results.

Well, there's a pretty strong indicator that different engines will do very different things with the same oil. Since 1985 or so, I've used Mobil-1 in a Dodge Aries (I hesitate to admit owning one, and probably wouldn't except it was a temp beater, had the 2.2L), a 1988 Honda Civic LX Sedan, a 1990 Mercury Sable (wife's car, with the 3.0L pushrod V-6) a 1998 Buick Regal GS (supercharged 3.8L), a 2001 Highlander (3.0L V-6), a 2001 Sequoia (wife's car, 4.7 V-8), a 2002 Camry (4 cyl, destroyed in wreck), and a 2003 V-6 Camry.

I'm no maniac, but I do push engines pretty hard and I live in a hot climate (gulf coast area), so I've been very happy with M-1. In what types of engines have you experienced the M-1 consumption?

leinad35 · Apr 15, 2004

How about the new Valvoline Max Life Synthetic? I have seen it at Advance Auto (but I didn't look at it closely).

Ð

haley10 · Apr 15, 2004

quote:

Originally posted by blsnelling:
What oil are you using? What synthetic would you recommend? I'm only seeping at this point and consupmtion is still not that high that I won't use synthetic.

Just using dino in this one (wife's car/low mileage).

The Rotella is cheap, but I'm afraid you'll see consumption here too.

I'd probably just stick with a great blend in 10W-30, but if you must.....

I'd give the GC a shot. Maybe on sale at Autozone now. It's 0W-30 and a thick 30wt.

GC, Amsoil, M1, or Rotella T Syn????

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