5W40 or 15W40 in 6.7 CTD?
So the owner's manual in my 2015 Ram says to use 15W40 oil in the 6.7 Cummins diesel, unless the temp is going to routinely be below 0*, in which case you should use 5W40. Here on Long Island, the ...
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Let me preface this by saying this is NOT a recommendation.
I recently retired from UPS in the Automotive department, 9 years as a diesel mechanic and the rest of my career managing the shops.
UPS has the largest privately owned fleet of vehicles in the world so cost is a huge factor, I am going to tell you something you will not believe but trust me, it's true.
Around 20010, in an effort to reduce costs and after discussions with the various suppliers, UPS decided to use 10w30 exclusively in all delivery vehicles. Cummins was one of our suppliers who signed off on this decision.
We have been running 10w30 in all 5.9 and 6.7L Cummins, with a 15,000 oil drain interval since that time with no ill effects. Read that again. Most 6.7L engines exceed 500K miles with only water pump, turbo, injector, EGR valve and maybe EGR cooler replacement. I know of one in particular with over 600k miles that still only consumes 2 qts of 10w30 between those 15,000 mile oil changes.
The primary cause of CTD failure is injector failure, stripping the cylinder walls of lubricant. If it starts missing or smoking SHUT IT OFF until the cause is corrected.
Again this is not a recommendation, just interesting results of a huge real world reality.
I recently retired from UPS in the Automotive department, 9 years as a diesel mechanic and the rest of my career managing the shops.
UPS has the largest privately owned fleet of vehicles in the world so cost is a huge factor, I am going to tell you something you will not believe but trust me, it's true.
Around 20010, in an effort to reduce costs and after discussions with the various suppliers, UPS decided to use 10w30 exclusively in all delivery vehicles. Cummins was one of our suppliers who signed off on this decision.
We have been running 10w30 in all 5.9 and 6.7L Cummins, with a 15,000 oil drain interval since that time with no ill effects. Read that again. Most 6.7L engines exceed 500K miles with only water pump, turbo, injector, EGR valve and maybe EGR cooler replacement. I know of one in particular with over 600k miles that still only consumes 2 qts of 10w30 between those 15,000 mile oil changes.
The primary cause of CTD failure is injector failure, stripping the cylinder walls of lubricant. If it starts missing or smoking SHUT IT OFF until the cause is corrected.
Again this is not a recommendation, just interesting results of a huge real world reality.
