Do some motors like thicker oil?

Status
Not open for further replies.
Not exactly, but I do review them myself from time to time. After seeing your post, I took another look, searching just the term "vq" in only the UOA Gas sub-forum. We are now into the 4th page of results (a few are from other vehicles in which the VQ came up during discussion of the other vehicle). My current summary would be: all examples of GC use (about eight or so cases) produced what we here would call outstanding results. The xw-30 oils other than GC are all over the map. There are a few solid performances, and a significant number of real stinkers, and a surprising number of these are with Mobil 1 (Amsoil TSO 0w30 also did not show well). The one documented case of use of a 40 wt oil produced good results (with Fe at 11, but that's not bad for this engine). It, btw, was not the spec-ed 10w-40, but instead was Chev Delo 400 15w40.
 
ekpolk, I really have no more than a passing interest since I don't own one of these engines, but the few used oil analysis I looked at that weren't outstanding always had some kind of extenuating circumstance that made them less than useful to judge what is favorable to this engine. For example, a single UOA, after switching brand/viscosity of oil, I consider pretty much useless, especially if there's a substantial change in the basestocks.

GC does well in many engines, and also given the analysis given by Terry, this indicates to me this has more to do with the basestocks and formulation, than the viscosity.

Additional, seems to me that the VQ line is large, and includes displacements from 2.0L to 4.0L so I don't know how identical these various incarnations are.

Presently, I'm not sold on anything other than GC seems works well in this engine, and that may only be a reflection of the care the engine receives from a BITOG GC user.
 
427Z06: Thanks for the Steve Bergin article. It helps to explain the awesome used oil analysis that we keep seeing from 5w20 oils (in engines that are spec'd for them). I'm really starting to believe that these car company engineers might actually know more than we do about what is best for 'their' vehicles.
wink.gif
 
Goldenrod said: I'm so old, I can remember when 10w30s first came out and hearing guys say "that oil is too thin for my motor."
-----------------------

I too remember when 10w30 was introduced. SAE-30 was the common oil (at least in temperate climates) at the time, with SAE-40 going into engines with known wear. When 10W-40 came along, I decided to try it, then switched to 20W-50 all the way up through my 1986 Olds 3.8L which had 260,000 miles on the engine when the car got totaled in a minor fender bender (a 260,000 mile car ain't worth much).

My next car was a 1994 Olds 3.1L which got 10W-40 (in year 1999 when I bought it with 8K miles on it). My wife totaled that one.

My next and current car was a 3-yr old 1998 3.1L Grand Prix which got 10w30 (even though 5w30 is listed on the oil cap). For the last couple years I've been running SAE-30 in it from May thru Oct, and 10w30 from Nov thru April. Pennzoil. Two oil changes per year, approximately 7000 miles between changes. The car now has 120,000 miles on it. With the 10w30 it'll use 1 quart between oil changes (7000 miles). With the SAE-30 in it in the summer, oil consumption is about 1/4 quart. Car does a lot of local driving and frequent 15-20 mile freeway runs at 75+ mph.

I still like thick oil. Keeps moving parts from touching together.

Regards, Gary in Sandy Eggo
 
quote:

Originally posted by Gary in Sandy Eggo:
(snip)
I still like thick oil. Keeps moving parts from touching together.

Regards, Gary in Sandy Eggo


Ahh Gary, but here's the rub (ooops, that's a pun, isn't it...): it only keeps them from touching after it has "arrived on the scene." And as our used oil analysis seem to show, in most cases involving passenger cars, once it gets there, it really doesn't seem to do any better keeping the moving parts from touching than its thinner relatives.
 
427:

I'll join pbm in thanking you for the article. This time, I've saved it. I was actually thinking of it yesterday as I was performing my little mixing experiment. I agree with the premise, within the wide bounds of reason (which I suspect the author meant, but didn't feel the need to say, given the context). But that straight SAE 60 pours amazingly slowly, even at room temp. I can't imagine that any good could come of using it in an engine meant to use 20 or 30 wt oils.

I agree that a good number of those VQ used oil analysis would need to be tossed from any rigid attempt to draw conclusions, for the reasons you stated. First use used oil analysis = nearly meaningless, except for gross physical damage issues.

It may be that the GC brewmeisters handiwork is largely responsible for the oil's good showing. There is another related clue, though. When the first VQ appeared as a 3.0L (is your 2.0L figure a typo, or is there an exotic "tiny VQ" that I've missed?), it spec-ed only the 5w and 10w30 oils. With the appearance of the 3.5L version, they added 10w-40 to the list. Given the apparent meta-shift toward lighter oils that's taking place in the industry, I think that the appearance of 10w-40 is a strong suggestion that the designers believe that slightly thicker is better for this engine. Thick-ish GC's good showing could be related to whatever physical reality is driving the engineers to spec heavier oil (then again, maybe it's not...). It certainly is a tantalizing question.

The wide variety of uses of this engine, and sizes do also make the analysis difficult. The 3.5 is presently installed in everything from Quest vans (making "only" 240 hp), all the way to high line M35s and 350Z sports cars (where it makes around 300 hp). Differing modes of use, intakes, valve timing schemes, and so forth, may all be confusing the picture. I think we'd all expect to see different results from a soccer mom in a Quest vs. a guy with a 350Z track car.

And yes, GC use may be an indicator of that n-th degree of car care excess, but on the other hand, doesn't that same idea apply to most people who join this forum and take the time to do a used oil analysis? I'll certainly agree that no unqualified conclusions can be drawn as to this engine's tastes, but there are nevertheless some strong indicators. I'll keep watching, and since I DO own a VQ, I'll pass the word if any info surfaces which sharpens the focus in either direction.
cheers.gif
 
Good analysis, ekpolk. I especially like the point made that this engine is used in a "wide variety" of applications. Maybe the engineers(?) went for a strategy of covering all the bases in a general sense, since I think we(?) tend to emphasize viscosity over an equally likely and/or the more important base oil and formula contributions. In short, many GC users are obsessing over the right product for the wrong reason.

Here's the reference for the 2.0L comment:
http://en.wikipedia.org/wiki/Nissan_VQ_engine

Increasing engine size and/or power levels without a redesign of other components could require a increase in viscosity. But that's generally not the preferred way of dealing with it if it's a high volume production engine.

If you do run across any clear cut UOA evidence of this engine's preferences, please keep us informed.
cheers.gif
 
Very interesting. Wiki of all places. . . I'd heard there were other VQ versions overseas, but not that they were smaller displacement. I guess it's true -- learn something new every day. Still, growing up and driving in the 'States, somehow the the concept of a 2.0L V-6 just seems wrong. I guess I'm just a big ugly American.
wink.gif
cheers.gif
 
I've thought about putting a heavier oil in my 2002 Cavalier 2.2 OHV engine as well. I have 5w30 in it and it is really shaky and noisy when cold, and only gets smooth when it gets warm. I know engines get smoother as they warm up, but the less noise (piston slap), and just HOW smooth it is when warm makes me think that this slightly loose engine would benefit from a thicker oil.

The Wal-Mart near my house stocks XD-3 0W-40; I'm thinking of trying that when I can run it on an extended drain. I'd also like to try GC....so many oils, so little time....
 
quote:

Originally posted by GoldenRod:
You guys are tempting me to try GC in my little GM 3.8L V6. But the price is so much steeper than I have ever payed for on an oil, that I would be expecting a HUGE difference. That little motor is a good running motor, but I'm still on a never ending search for quietness and smoothness.

LOL, Supertech makes 20W50! Wow, you think the 3.8 is little.....that's old school.
grin.gif
I've been driving little cars so long I wouldn't know a v-6 if it feel on me.
grin.gif


I don't think there's much that can be done to quiet a GM 3.8l. It's a loud stacatto sounding engine. I can tell a 3.8 coming from a mile off. I have to admit that the 3.9 w/ vvt or whatever interests me, though.

I think you'd be fine. That's a relatively stout engine.
 
Liking thicker is not gospel with any engine ID.

Pretty-much need to try it & see what occurs. But, there's no sense in going there if your engine has no issues. Consumption, engine sound/cleanliness & used oil analysis should decide that.
 
I don't think that a heavier oil will hurt MPG that bad, will it? I mean, people claim 5mpg loss when going from Mobil 1 to GC but there isn't much of a difference in cst.

Maybe 5mpg loss going from 5w30 to 20w50? Has to be harder on the oil pump too?
 
5MPG! No way, there isn't that much parasitic loss between pumping a 30wt vs 50wt oil.

BTW, GoldenRod, I still use 10W40 and even SAE30.
cool.gif
 
quote:

"Journal bearing damage and failure are caused by the thermal overload that occurs when the oil supply is cut off. Mechanical overload does not cause journal bearing failure -- except in the isolated case where extreme mechanical thrust overload can cause attached flanges to fail, regardless of oil viscosity."

Seems like a good reason to run Redline Oil. If your pump fails an you don't notice right away, the Redline probably will see you through without damage as it won't likely suffer thermal overload.
 
Status
Not open for further replies.
Back
Top Bottom