0w vs 10w starting properties.

[The_Nuke]

Originally Posted by JavierH19
Hello everyone, I have an old 05 GMC Sierra 6.0 as a work truck and it has 323k from when I bought it new and it has never had an engine or transmission component replaced other than the alternator. The internals are all original. The engine has developed a small tick about 4 months ago that does goes away when at operating temp.

Would it be a good idea to switch from 5w-30 what I've always used to 10w-30 or 15w-40 universal?. I don't think 20w-50 is necessary but if any of you recommend it I'll try it.

Would the thicker oil at cold temps provide better protection and help the small tick since the coldest it was this year was around 35f. Now it's around 50-70f in jan-feb but the extra thickness couldn't harm could it? and is it possible that too thin oil is bad when it isn't needed? I always thought the thinner the cold oil the better but now I'm not sure since it's not even that cold to begin with.


Given the facts at hand, I think it would be a fool's errand to switch horses mid-stream. I say stick with what you're using now for engine oil.

Personally, I've always thought it was a good idea to dance with the one that brung you, which seams especially applicable in this scenario.

And if none of that is persuasive, I do seem to remember some old philosopher from way back saying something along the lines of, "If it ain't fixed, don't broke it!" (I believe his name was Nuke-fucious, and he lived somewhere down in Texas the best anyone has been able to ascertain.)

 

[OVERKILL]

Originally Posted by 1JZ_E46
Originally Posted by OVERKILL
Originally Posted by 1JZ_E46
I see what you were getting at now. Be curious to know the KV of 0/5/10/15W-xx oils at 0C temp.


You can use a visc calc, they work down to around 0C, but lose accuracy significantly when you get below that.


Even with the amount of VII in 0/5W oils? I thought the operational viscosity calculator only really worked well for monogrades to any real accuracy.


Nope, they behave in a pretty linear fashion until you get below 0C, then things go sideways.

 

[1JZ_E46]

Originally Posted by OVERKILL
Even with the amount of VII in 0/5W oils? I thought the operational viscosity calculator only really worked well for monogrades to any real accuracy.


Nope, they behave in a pretty linear fashion until you get below 0C, then things go sideways. [/quote]

Good to know.

 

[y_p_w]

Originally Posted by OVERKILL
There are folks out there that think a 0w-xx is "like water" when cold and thickens up as the temperature increases. That was the potential impression I got from the OP, and what I was trying to clarify as per his perception as to how this worked. Hope that clears that up.

Does anyone really think that oil gets thicker with higher temperatures?

And again - SAE viscosity is definitely a blunt tool since there's so much in between the two extremes. Also, there are so many different variables, including thinning and thickening with use.

 

[OVERKILL]

Originally Posted by y_p_w
Originally Posted by OVERKILL
There are folks out there that think a 0w-xx is "like water" when cold and thickens up as the temperature increases. That was the potential impression I got from the OP, and what I was trying to clarify as per his perception as to how this worked. Hope that clears that up.

Does anyone really think that oil gets thicker with higher temperatures?

And again - SAE viscosity is definitely a blunt tool since there's so much in between the two extremes. Also, there are so many different variables, including thinning and thickening with use.


Yes, there are people that have thought that way. I've had to reply to that thought process a few times on here.

 

[PPWarrior]

try a 20w50 if you are worried about ticking

 

[Oro_O]

Originally Posted by 1JZ_E46
I see what you were getting at now. Be curious to know the KV of 0/5/10/15W-xx oils at 0C temp.


This does not show exactly what you want, and it's a little tricky to read because the y-axis is logarithmic. But this is 0w-30 vs 10w-30 exmples of unspecified "major brand" oils from and SAE paper discussed here a while back.

The idea that a 5w-xx or 0w-xx flows appreciably better when "cold" where "cold" means the engine has sat overnight (but the ambient temp is above freezing) is just wrong. Also, this is virgin oil, so the VIIs that keep the 0w-xx from thinning as much at 100C have not been sheared down yet. The 10w-30 would compare even better if it were a UOA. The 0w won't retain those characteristics as well over time.

So if the OP is in Texas and it's not way below freezing often in locale, by all means run the 10w-30 all the time.

As to ticking, I don't know that engine at all. A little listening will let you differentiate between header noise from lifter tick. If lifter tick, try a quality synthetic; I cured my truck of it with a four-hour interstate drive on a fresh fill of Mobil 1 10w-30 HM. Had run HDEO for years, then switched to that and the tick it had for five years was gone in a day.

 

[JLTD]

Originally Posted by MParr
It's a GM V-8, it's going to tick. It's what they do. 10W30 won't hurt a thing.


Especially in TX!

 

[kschachn]

Plus the dude lives in Texas. Unless it is below freezing there isn't going to be a meaningful difference between an 0W, 5W or 10W oil at startup.

 

[WyrTwister]

I drive a work truck . 2007 Silverado , V-8 , with 240,000 miles on the clock . If the temp is ~ 30F or lower , when I start up in the morning , it ticks . Last oil change I had the oil change place put in thicker oil . Can not tell any difference .

The question of piston slam has been asked on another thread . I do not know .

 

[1JZ_E46]

Originally Posted by kschachn
Plus the dude lives in Texas. Unless it is below freezing there isn't going to be a meaningful difference between an 0W, 5W or 10W oil at startup.


Exactly. I ran a few numbers in an operational viscosity calculator and at 0C and above, the W rating doesn't mean much. At 0C the viscosity mainly depends on the KV40 viscosity.

 

[WyrTwister]

In our part of Texas , I can remember a VERY few times it hit -10F to -15F . Our GM vehicles indicate 5W-30 , so that is what I use .

Texas is big enough , where in Texas makes a lot of difference in climate .

My understanding is , the multi viscosity oil behaves like a single viscosity oil of the same ( second number ) at about 200F ? So a 5-W-30 behaves like a 30 single viscosity at " normal " engine operating temperature ?

 

[Triple_Se7en]

Originally Posted by 1JZ_E46
Originally Posted by kschachn
Plus the dude lives in Texas. Unless it is below freezing there isn't going to be a meaningful difference between an 0W, 5W or 10W oil at startup.


Exactly. I ran a few numbers in an operational viscosity calculator and at 0C and above, the W rating doesn't mean much. At 0C the viscosity mainly depends on the KV40 viscosity.


OP states in his opening post that the ticking stays until operating temps occur. So this tick is way beyond startup.

 

[kschachn]

Originally Posted by WyrTwister
In our part of Texas , I can remember a VERY few times it hit -10F to -15F . Our GM vehicles indicate 5W-30 , so that is what I use .

Texas is big enough , where in Texas makes a lot of difference in climate .

My understanding is , the multi viscosity oil behaves like a single viscosity oil of the same ( second number ) at about 200F ? So a 5-W-30 behaves like a 30 single viscosity at " normal " engine operating temperature ?

Even at -10F to -15F there still isn't much of a difference between the 0W and the 5W oils. It's just not cold enough, not until you are well below 0F does it matter. At -35F you start to see a bigger deviation.

A 0W-30, a 5W-30 and a 10W-30 are all 30 grade oils. That is how they are defined and tested.

 

[y_p_w]

Originally Posted by WyrTwister
In our part of Texas , I can remember a VERY few times it hit -10F to -15F . Our GM vehicles indicate 5W-30 , so that is what I use .

Texas is big enough , where in Texas makes a lot of difference in climate .

My understanding is , the multi viscosity oil behaves like a single viscosity oil of the same ( second number ) at about 200F ? So a 5-W-30 behaves like a 30 single viscosity at " normal " engine operating temperature ?

The exact temperature for evaluation is 100ºC (212ºF). The oil temperature should be more or less regulated by the coolant/thermostat, but oil temps are always going to be higher than coolant temps. and might even go higher with higher ambient temps, track use, towing, etc.

There are a lot of ways the oil is supposed to cool. I believe airflow over the oil pan will cool it a bit. An oil to coolant heat exchanger is more effective. My current car has one, where the oil filter mounts on the oil cooler. I can see the coolant hoses going in/out. The are other types too. So even though the "30" is a range of viscosity at 100ºC, the oil is probably going to be operating at higher temperatures than that. I think turbos also tend to subject oil to higher temps, even though most are water cooled these days.

 

[JohnnyJohnson]

Originally Posted by WyrTwister
In our part of Texas , I can remember a VERY few times it hit -10F to -15F . Our GM vehicles indicate 5W-30 , so that is what I use .

Texas is big enough , where in Texas makes a lot of difference in climate .

My understanding is , the multi viscosity oil behaves like a single viscosity oil of the same ( second number ) at about 200F ? So a 5-W-30 behaves like a 30 single viscosity at " normal " engine operating temperature ?


Even Pennzoil 10W-40 has a pour point of -39.

 

[kschachn]

Originally Posted by JohnnyJohnson
Even Pennzoil 10W-40 has a pour point of -39.

And likewise Mobil 10W-40 HM is -42C, goes to show why pour point wasn't necessarily a good marker for pumpability.

 

[DriveHard]

Put this together for a little comparison...

 

[OVERKILL]

Originally Posted by DriveHard
Put this together for a little comparison...



Keep in mind that below 0C (32F) the accuracy falls off a cliff.

 

[Patman]

Originally Posted by 1JZ_E46
Originally Posted by OVERKILL
I get the impression you think that the number in front of the W is a viscosity number and that a 5W-xx is "5 thin" when cold and a 10W-xx is "10 thin" when cold. Is this correct? Because if so, that's not how it works.


Very true. Having said that, I'm sure there is a linear correlation between the "W" rating and an oil's thickness at a particular cold temp. It's probably just less exaggerated than the OP expects.


That is something that confuses a lot of people, I see it all the time on other car forums (and sometimes on here too). People will say things like "a 5w30 oil behaves like a 5 weight oil when cold and a 30 weight oil when hot" and they actually believe that the oil starts out thinner and gets thicker as it warms up.