Much better oil pressure after oil change.

[Larryjb]

It does reduce longevity especially when they are running higher temperatures too. Grumpy Bear over on the GM-Trucks forum has been studying and posting about this for years with the K2s. I'm sure Blackstone-Labs has plenty of data too.

Already there is an error here. My 2002 Tahoe runs at about 95C (200F), which is pretty much the same that my 92 Grand Marquis ran at. This was the same temperature that my 81 Lemans ran at. The water jackets surrounding the cylinders cannot be that much different from the block. The only variable I can see affecting the oil is that the oil may absorb more block heat than in the past, but I can't see that being an issue.

What I see as being a bigger issue is the design of the engine with tighter clearances. I found this article, which I would believe over a pseudo experiment "published" on a forum: https://www.lsxmag.com/tech-stories...rication-should-you-run-higher-viscosity-oil/

It is stated that a thicker oil will cause more wear than the lighter oil, because 70% of engine wear occurs on cold startup. You want the oil flowing to critical parts as fast as you can get it there.

 

[swathdiver]

It is stated that a thicker oil will cause more wear than the lighter oil, because 70% of engine wear occurs on cold startup. You want the oil flowing to critical parts as fast as you can get it there.

This is true. What's not mentioned is the thicker oils higher resistance to shear. A lower viscosity oil has less resistance to shear at higher temperatures then higher viscosity oils. If you can lower the temperatures, then you can reap the benefits of running the lighter weight oil. The engineers keep the temperatures up for emissions compliance, not performance or longevity.

PS> Just read the article and it is helpful but fails to mention temperature as the cause for shear falling off due to high rpms and horsepower. Heat makes horsepower, rpms generate friction and therefore heat.

 

[OneofFew]

IM kinda old school and live in the south. I just don't think 5w30 is the right choice for me in a climate that sees 100 degree heat and even in the deepest winter does not see temps below the teens. In the summer I run 10w30 in gas engines. All of my vehicles without cats run 15w40 HD diesel oil in summer. In over 2m miles run, I have never blown an engine.

I do still think that CAFE standards have influenced manufacturer's recommendations in viscosity and running a lower viscosity oil can effect longevity. Do I have proof? no. Is it possible that advances in oil technology warrants a change in viscosity recommendations? Yes.

 

[Rocket Man]

IM kinda old school and live in the south. I just don't think 5w30 is the right choice for me in a climate that sees 100 degree heat and even in the deepest winter does not see temps below the teens. In the summer I run 10w30 in gas engines. All of my vehicles without cats run 15w40 HD diesel oil in summer. In over 2m miles run, I have never blown an engine.

I do still think that CAFE standards have influenced manufacturer's recommendations in viscosity and running a lower viscosity oil can effect longevity. Do I have proof? no. Is it possible that advances in oil technology warrants a change in viscosity recommendations? Yes.

Does your engine run hotter in that environment than the rest of us? Or does the thermostat and cooling system maintain it, because in that case the outside temp doesn’t matter, correct? Or am I missing something?

 

[Larryjb]

I remember reading somewhere that the lifters are designed with smaller oil ports than previous engines, and this is part of the reason a lower viscosity oil is required. I do notice that my engine ticking on a cold start settles down quicker with 5W30 than 10W30.

 

[brasil]

in the late 90th i owned a 300SL Mercedes. With a six cylinder engine. The engine made a lot of noise ( lifters ) at start up in the morning. I asked a Mercedes engineer here in the town where I live- if he could give me a good advise. He gave me a very good one. He told me to switch from 10-40 over to. 0W 40. ...yes 0 w 40 ! followed his advise. Noise from the went away..after the first start up and the oil pressure even with hot oil....was still good.

The secret is the "0 "..this oil is very thin when cold...so the lifters are filled faster as with a 5 W or 10 w oil. While hot the 40 is the same as the 10w40 or 5w40...

Greetings Juergen

 

[iamdub]

Does your engine run hotter in that environment than the rest of us? Or does the thermostat and cooling system maintain it, because in that case the outside temp doesn’t matter, correct? Or am I missing something?

Of course. Our 100-degree heat is different than your 100-degree heat.

It's not the heat, it's the stupidity.

 

[BG1988]

That's a pretty generous claim that a recommendation of lighter oils causes reduced engine longevity. I trust you have data or some sort of study we can reference?

The correct answer is, when covered by a film of liquid sufficient to reduce the coefficient of static friction between the engine block and the piston/lifters etc... to essentially zero, but not so deep as to introduce a new source of friction.

 

[OneofFew]

Does your engine run hotter in that environment than the rest of us? Or does the thermostat and cooling system maintain it, because in that case the outside temp doesn’t matter, correct? Or am I missing something?

The reason colder climate oil recommendations are different is because of start up temperatures or do you disagree with that too?
Also, there is no means for regulating oil temperature on these. The colder the environment, the colder the engine oil.

 

[OneofFew]

Update: Oil analysis shows lead (15) from bearings and sodium(161) and potassium(47) from coolant. I have not been loosing any noticeable amount of coolant. I do have a lifter tap on cold start that gets louder when I raise the idle (at least I think it's a lifter tap) and get a 'low oil pressure' light when stopping to back into my driveway from the hill.
So my theory is that bottom end bearings are worn from coolant, lifters worn from age, etc, possibly an oil pickup tube O ring issue and an intake gasket leak resulting in cold engine stumble and a slight crack in the head or head gasket (not surprising given it's history of neglect)

Blackstone labs recommended increasing my oil change interval to 2k miles to reduce coolant accumulation.
I will try 10w30 dino oil and add some Lucas oil. If the bottom end is the issue, this should quiet that, if the lifters are an issue, this will exasperate that. No good solutions IMO, I think the engine is about done.