Yeah, I was talking temperatures.

I've owned it for 15 years. I used to live in the Mojave desert and now live near the rockies. It'* seen years of both temperature extremes (and actually have started it cold at 30 below a couple of times). It'* also been down to sea level and over 11,000 feet above sea level.

. . . and yeah I haven't found the governor yet. The speedometer only goes to 100MPH. I have come to know that on a closed course with a professional driver it'* happy to do this all day long. Do not try this at home. Yada yada.

They are definitely better at fast straight than fast turns.

Thanks for letting us know how it came out!

I run 5w20 in my 96 all day long, thinner oil moves through the engine quicker at startup and creates less drag while running , oil pressure means the oil has resistance to flow, you want flow, yes you need a certain amount of pressure but higher isnt always better, oils nowadays are way better than when these cars where made, also I would hope you are not planning on taking turns at 110mph..the only time you would have body roll isn't a factor until a turn, .

I've heard some good ones before, and everyone is entitled to their opinion, but recommending 5W20 for any production 3800 will cause long-term issues. Much of the engine was designed in the 1960'* and revised from there.

Thinner oil bleeds out of lifters and bearings more quickly. The engineers didn't ever design around 5W20 on the 3800, even in cold conditions. Is there something you know that they don't?

So at that rate we could all run 0W20 and get better flow???

Have you measured the gains you get from thin oil?

Does 5W20 cost less?

To that point, I am unaware of a GM engine that GM recommends running a thinner viscosity than 5W30 at least up to 2010ish, even with all the struggle for more power and fuel economy. Maybe on some of the little 2011+ world engines or something that I don't pay much attention to . . . ?

Yes, but I want adequate pressure even more than I want flow. This isn't air or fuel flow we're talking about. It'* the resistance to flow that creates pressure that suspends metal parts with tight clearances from touching other metal (and sometimes plastic) parts with tight clearances.

Your car may appear to run fine on 5W20 today. I'd like to see how the same engine is doing in 100,000 miles of this.

This is certainly true, since "higher" could mean any number up to infinity. Based on this, most numbers would be too high of a pressure measurement for a GM 3800 so that makes your statement factually correct. Within the context of the GM 3800, I've never heard of one running at too high of an oil pressure even with a high-flow oil pump. Advising someone to run thinner oil based on this thinking would be unsound advice. Then there'* the question of "What gain is had by doing this?"

That doesn't mean that a given engine is engineered for thinner oils no matter how good oil is nowadays. Viscosity is the base measurement for engine oil regardless of how modern it is. Oil needs to stay in bad situations long enough to do its job. GM learned a lesson about this recently with timing chains on their 3.6VVT engine. Even with "thick" 5W30 in a modern engine, extending the oil changes a little too much (within GM'* specifications) costed them millions in recall repairs.

Depends on the bank angle.

Body roll is also an issue on uneven road surfaces, in gusty crosswinds, and as a result of turbulence from moving in and out of a draft.

first off gm engineers where not basing the series II 3800 or even the series I off a 60s design, this is a totally different engine than the 60s and 70s 3.8 , they where having to do with making these engine much more fuel efficient, Thinner oil means less drag, there isn't a damn thing wrong with thinner oils nowadays either, they provide more protection now than 10w30 or 40 did back in the 80s and early 90s, second, you obviously dont understand how oil works , the first number is the cold viscosity, and second is the viscosity at operating temp, after a few min of running the 5w30 is the same thickness as a 10w30 it just flows better when cold, and going from 10w30 to a 5w20 and even a 0w20 will not hurt these engines, I have a 2014 f150 with a 360hp 5.0 with almost 200k on it and It has always gotten 0w20 and I have run the dog **** out of it loaded to the max towing **** halfway across texas and the country and its still running like a champ, now back to 5w20, at operating temp its gonna run like a 20 weight oil, which isnt to far below the 30 weight of the 10w30 , it the lifters had a problem they would clatter and I wouldn't have any oil pressure, and my 3800 has 160 k on it and the inside the the heads are clean as the day they where cast and I have 40 psi at idle hot, These engine do not have such excessive clearance that they have to run 10 weight or even 20 weight oil cold. unless your **** is already worn slap out, you have 0 reason to have to run a 10 or even 20w@ cold viscosity. . this is a qoute right from engine builder Magazine ".Reducing the oil clearance between the rod and main bearings and the crankshaft has a number of advantages. A smaller gap spreads the load over a wider area of the bearing surface and distributes pressure more uniformly across the bearing. That’* good, provided the bearing is strong enough to handle it. A smaller gap also decreases the volume of oil that has to flow into the bearing to maintain the oil film between the bearing and shaft.


That’* also good, provided the oil is thin enough (low viscosity) to flow well into the bearing. This also reduces the amount of oil pressure the engine needs, so some extra horsepower is gained by reducing the load on the oil pump."

these engines are not sloppy buildt 60 and 70s or even eraly 80s engines, gm have closed the main and rod bearing clearances up on everything since they started the newer style engines in the late 80s . mainly to run thinner oils to maximize fuel economy and engine longevity. notice even the most clapped out 3800 can run almost the 200k, the reason for that is tighter tolerances , better machine work and better oilds than we had back in the day, I to used to be an idiot they thought higher viscosity was better, I ran 20w50 castrol in everything, but then I learned , and started understanding how oil and engines really work and pushed all that old 70'* hotrodder bullshit out of my head. head over to bob is the oil guy forums and see all the engineers and people who run thinner oil and send it out for testing like a religion and they almost always have their samples come back with good results. get out of the old ways of thinking about oil and educate yourself on the way these engines are build, tighers bearing clearances, roller cams, thinner rings, no need for heavy oils anymore.

BTW this is my oil pressure after driving 45min on the interstate and then being stuck in a traffic jam.. 40 psi at a hot operating temp with 5w20 with about 600 miles on the current oil change.

Well, good for you. I was unknowingly running 5w20 for years and was met with higher oil consumption, lifter noise at hot idle, and insane preignition on hot days.

I didn't realize what was going on until the place I used actually put the oil weight on the paperwork when they changed computer systems. I started providing my own oil, the above problems either went away completely or vastly improved.

Then again, Series 1 could be a different animal in this regard.

I have 0 oil consumption issues. stays full for 4000 miles. just changed the plugs today and they where clean as a pin and really didnt need changed. no preignition issues, sounds like you need a rebuild, probably from using to thick of an oil. best of luck.

The 3800 was an evolutionary design over a long period of time. It did start life as a 3.2 liter relative of the Buick Aluminum V8 .

The GM 3.6 is a totally different different, as is the 3.4 . The 3800 Series I/II/III is an evolution of the 60'* Buick 198 V6. Just like the 2003 Vortec 5700 being an evolution of the 1955 Chevrolet 265 small block.

I agree with this within the context of using it in an engine designed for it.

I beg to differ.

Yes, knew this and agree with it.

What information are you are basing this declaration on . . . ?

If this ie true, why does your manual specifically say "If neither SAE 5W-30 nor SAE 10W-30 grade oils are available, SAE 30 grade may be used at temperatures above 40 degrees F (4 degrees C).Do not use SAE 10W-40, SAE 20W-50 or any other grade oil not recommended"

. . . ? If anythingW20 was safe to use in a 3800 series I/II/III why would GM specifically say "Do not use . . . or any other grade oil not recommended" ?

Yes, the Coyote is designed for 0W20 . Totally makes sense to me. There is currently a fleet of F650'* getting the snot beat out of them for UHaul and others that have 6.8 liter V10'* that run 0W20 and those are all fine too because they are designed for it.

Isn't far below 30W . . . and yet nobody professional will recommend it for 3800 series I/II/III .

This is incorrect. It'* not like you go below 30W and then suddenly it can't build any oil pressure at all. The regulator will bypass less though. Still doesn't mean parts are as well protected as 30W.

How much of that 160K is yours?

Thinner oil certainly wouldn't sludge easier. Not sure where you're going here.

Yes, the pressure regulator is bypassing less in order to achieve this result.

Except for the statements in the manual, and those of all of the major oil manufacturers in the United States.

You didn't tell me you custom built your 3800. Did you? If so, this would have saved all of us time. For a factory 3800 I'll go by what the factory recommends.

I agree on the reduced sloppiness . . . and yet they still recommend 5W30 and 10W30 in them.

I noticed. I have one with 228,000 right now.

I agree all of these help. The cars also got a lot lighter and more aerodynamic, and the fuels got a lot cleaner.

Ummm . . . If I were looking for trouble I might assume you are trying to group me in as an "idiot they thought higher viscosity was better". Glad to hear you came around though.

Ouch that'* terrible, unless the manual called for it.

Again I'll say: "everyone is entitled to their opinion". You are still talking public forums with no ability to verify the veracity of anyone'* claims. I get that you agree with the statements of these unverified individuals in these public forums. At the same time this doesn't make the "old 70'* hotrodder" BS incorrect for the `70'* technology, nor does it make the factory reccommendations for 1990'* engines "old 70'* hotrodder" BS.

Again, your sources of knowledge haven't convinced me. Your opinion appears to be that I need to educate myself. I have done so with manuals from those that designed and built my engine.

I'm still curious: