Heavier oil

[Smitty1021]

That's one hell of a lot of info but thanks. I realize that the initial smoke show at start up is the valve stem seals but my plan is to hopefully have a new motor within the next year so I was looking for a slight improvement or temporary somewhat solution to my issue rather than tearing everything apart. Thanks for all the help and info

 

[biga1987]

Definitely run a heavier oil than stock especially if your summers are killer like here in Texas. But if your running heavy oil also think of putting in a 180 thermostat. the engine will be working a little harder with the heavier oil.

 

[df2x4]

I've never run anything besides the recommended 5W-30 conventional, and I've never had any consumption issues in either of my trucks. Sounds to me like you guys have some internals that are getting tired.

 

[michael hurd]

Definitely run a heavier oil than stock especially if your summers are killer like here in Texas. But if your running heavy oil also think of putting in a 180 thermostat. the engine will be working a little harder with the heavier oil.

Fact: with the engine oil cooler in place, operating as normal, the average mean engine oil temperature will be within a few degrees of what the coolant temperature is. At very high friction surfaces like the cam lobes, the engine oil temperature will be much hotter than the average oil temperature.

Thin oil flows better, has less pumping losses.

Unless you have tuned the computer to make use of the 180 degree thermostat, I would recommend sticking to the factory thermostat.

A hot engine is an efficient engine, the lubricant has thinned to it's intended viscosity at operating temperature.

I don't understand the reasoning behind the use and recommendation of a 'thick' oil. Automatic transmissions create a lot of heat, and they use very thin oils, compared to an engine. Does anyone use a 'thick' oil in their automatic transmission? Would an automatic transmission benefit from using an oil as thick as 85w140 gear oil?

If it did, you would bet your bottom dollar that manufacturers would start using them.

 

[df2x4]

Unless you have tuned the computer to make use of the 180 degree thermostat, I would recommend sticking to the factory thermostat.

Agree with this 100%. I actually asked Justin at Black Bear Performance if there was any benefit to running a lower temp thermostat on these trucks, and he told me not to. Said that the Vortec motors like the factory thermostats the best. Needless to say I stuck with a factory thermostat in my tune.

EDIT - Also, very good points about the oil. Well said, Michael.

 

[biga1987]

Fact: with the engine oil cooler in place, operating as normal, the average mean engine oil temperature will be within a few degrees of what the coolant temperature is. At very high friction surfaces like the cam lobes, the engine oil temperature will be much hotter than the average oil temperature.

Thin oil flows better, has less pumping losses.

Unless you have tuned the computer to make use of the 180 degree thermostat, I would recommend sticking to the factory thermostat.

A hot engine is an efficient engine, the lubricant has thinned to it's intended viscosity at operating temperature.

I don't understand the reasoning behind the use and recommendation of a 'thick' oil. Automatic transmissions create a lot of heat, and they use very thin oils, compared to an engine. Does anyone use a 'thick' oil in their automatic transmission? Would an automatic transmission benefit from using an oil as thick as 85w140 gear oil?

If it did, you would bet your bottom dollar that manufacturers would start using them.

And if you do not have an oil cooler?

Transmissions are hydraulic. That's why it's a thinner fluid.

 

[Smitty1021]

Funny you guys mention the 180 thermostat. I actually just pulled my 180 out to replace it back to the 195 that was originally in there. Why is it that the 305's require 5w-30 and the 350's require 10w-30?

 

[Dr.Zoom]

From my owner's manual which only talks about 5.7 and 7.4:

As shown in the chart, SAE 5W-30 is best for your
vehicle. However, you can use SAE IOW-30 if it’s going
to be 0°F (- 18°C) or above. These numbers on an oil
container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 2OW-SO.

And my cap has 5w-30 on it.

Where did you get that info?

 

[df2x4]

From my owner's manual which only talks about 5.7 and 7.4:


And my cap has 5w-30 on it.

Where did you get that info?

You are correct, I was thinking of a conversation about a different vehicle's oil earlier in the day. Same for the 4.3L as well. Brain blip! Edited the original post to avoid confusion.

 

[superdave]

Valve seals would be an afternoon job and a better solution than monkeying with oil. I don't think going to 10w30 is going to make much of a difference.