10W-30 to 5W-40

Not open for further replies.
Nov 28, 2005
North Vancouver BC
For all you Oil Whizzes out there.I have a 03 2500HD with a 6.0 that is due for an oil change soon. I was planning on changing from a 10W-30 Synthetic to a Redline 5W-40 Synthetic as I really like the HT/HS numbers of the Redline Oil. I have read a lot of good stuff about the Redline so I thought I would give it a try. The outside temp ranges from about -1F to around +90F. Would I notice a difference in mileage with the 5W-40 as opposed to the 10W-30? Also, would there be a better high temp protection factor with the 5W-40. What would you folks recommend I use? Any info and opinions will be greatly appreciated.
Why do you want to change from 10W-30 to 5W-30? For typical gasoline vehicle according to manual, the 10W-30 is the universal lube. Better check with your car manufactor before make the switch.
Red Line 5W-30 gives you the HTHS of several 40 wt. oils yet has the benefits of better start up and around town performance and increased MPG. aehaas
AEHaas The Redline 5W-30 has a HT/HS of 3.8 whereas the 5W-40 has a HT/HS of 4.6 which is almost 1 point higher. This would mean to me that the 5W-40 would offer better shear protection. Also the 5W-40 has a higher viscosity index as well. Do you think the 3.8 is adequate or is it better to move up to the 5W-40 with the 4.6 HT/HS.
Maxima: I want to change to the 5W-40 from the 10W-30 because of the higher HT/HS number and having the extra protection of the 40W. I pull a 6000lb trailer through the mountains in the summer and my GCWR is around 15,000 lbs. That kind of weight builds up a lot of heat and engine stress and I don't want to have to change the oil in the summer, I would rather use the same grade all year round. BTW,GM recommends the 5W30.
Not quite sure why the huge worry about shearing in GM V8. Seems to me some dinos with HTHS around 3 do really fine in these engines. Shopping by HTHS only is very one dimensional and misleading, IMHO. Redline 5W-40 is a fine oil as is the 5W-30 - but they should be evaluated by matching viscosity with GM requirement, OCI expectations, price, previous UOA performance (in like vehicles, in like driving conditions, etc) with HTHS thought of as theoretical number (kind of is) that may or not be important for comparison to an engine manufacturers requirement as a pass gate.
If your vehicle calls for a 30 wt oil then looking over most of the dino 30 wt. oils shows an average of 2.9 - 3.1 range for the HTHS. The Red Line being at 3.8 is already in the range of many of the dino 40 wt. oils. It is a mistake to think that thicker and thicker is better. What is best is what the engine was designed to use tailored to your driving situation. If you drive mostly around town then thinner oils are better but if you are pulling loads up long mountains at high speeds and for long distances than a thicker oil may be better. I would use the Red Line 5W-30 in your situation and run a UOA after 1,000 miles when under load and see what happens. aehaas
Not open for further replies.