1994 Chevy 6.5 diesel

[renegade_987]

This is my cousins truck (I ask for alot of recommendations for them, they have alot of cars and never change oil). Anyways, AMSOIL says it takes 7 qts of 15w40, but since winters are so cold, would a 5w40 be better to use? Im guessing it's a Detroit diesel. TIA

 

[DrDusty86]

For the 6.5L 5w40 is fine. I would make sure the GP relay/controller and GPs are all good. Also in the winter if it has a cord plugging er' in will make it a lot smoother in the mornings

 

[Lead Shoes]

In Iowa I would go with Rotella t6 5w40 because its going to get cold, and 5w will make for an easier cold start up.

 

[dnewton3]

The new T5 in 10w30 has the same cold cranking rating as does the T6, for a lot less cost.

 

[renegade_987]

Is 10w30 OK for a 15w40 application?

 

[bullwinkle]

The 6.5 actually specs a 10W30 for colder/winter conditions, I run SAE 30 conventional year-round in my '93 6.2 diesel GMC pickup-but it gets a LOT colder in central Iowa than SW Ohio!

 

[renegade_987]

Originally Posted By: bullwinkle
The 6.5 actually specs a 10W30 for colder/winter conditions, I run SAE 30 conventional year-round in my '93 6.2 diesel GMC pickup-but it gets a LOT colder in central Iowa than SW Ohio!


You got that right! AHe needs something that will work in sub-zero temps. Would a straight 30 be to thin for this application? (Rotella T straight grade, for example)

 

[roadrunner1]

Select a 10w30 HDEO and call it a day.

 

[bullwinkle]

My 2 6.2 owner's manuals (the '93 and my now-scrapped '85 Sub) both recommended straight 30 for continuous operation, and I still have some of the AZ Delo 400 closeout 99cents/gallon stash left that I run in the 6.2 and an '89 7.3 IDI non-turbo F-450. The straight 30 should only be used in over 30F weather, so I use a magnetic oil pan heater for a few hours if I need to use them in cold weather.