CNG/LNG oil question

[JDenholm]

I'm doing some reasearch on motor oil used in compressed natural gas vehicles such as the trucks delivery companies operate. Someone has told me that the motor oil undergoes a chemical reaction when used in a CNG vehicle. Is there any truth to this or is the used oil generated chemically identical to what you'd drain out of a conventional gas or diesel engine?

Thanks for your input!

 

[Dualie]

There are special oils developed for Big CNG engines in stationary applications but after talking to the local power company's fleet mechanic that works on all of their CNG vehicles from their Westport Innovations 14L (Converted Cummins ISX) in their Kenworth Day Cab to their F-150's that run on CNG they use HDEO 15W-40 in the big bores and the same oil the Engine manufacturer specified when it was running on pump gas

 

[StevieC]

From what I understand the oil becomes more acid more quickly and needs to be changed more often or else you need to use an oil formulated for this purpose which has more additives that keep it neutral longer.

You can use any motor oil, just not as long...

 

[Shannow]

Depends on the source on the NG.

If it's mains supplied natural gas, then it will do next to nothing deleterious to the oil.

If it's landfill gas, the oil needs to be very robust to put up with the contaminants.

 

[Silk]

I still see oils in our market with a double diamond CNG/LPG logo meaning it's good for gas.I think they are low ash.

From my experience over 20 years ago when we had a lot of gas powered vehicles on the road,the problems came from extended oil change intervals,and low quality bearings.Because the oil stays visibly clean for 20,000km,30,000km or more,people were leaving the oil in for a long time....until it became ''dirty.'' This caused a build up of acid,which leached the lead from copper/lead bearing shells.You would pull an engine down,and the bearing shells were almost pure copper,with no lead on them.This was mainly an Australian engine problem....they were a prime candidate for conversion to gas,and used cheaper bearings.Changing to higher quality bearings,and staying with the recommended oil change intervals solved the problem.But the stigma still remains - you'll still hear people saying how CNG will ruin the bearings.

 

[Steve S]

Originally Posted By: Dualie
There are special oils developed for Big CNG engines in stationary applications but after talking to the local power company's fleet mechanic that works on all of their CNG vehicles from their Westport Innovations 14L (Converted Cummins ISX) in their Kenworth Day Cab to their F-150's that run on CNG they use HDEO 15W-40 in the big bores and the same oil the Engine manufacturer specified when it was running on pump gas

+1

 

[hogpops]

Growing up on a farm in the Texas Panhandle, we had natural gas fueled 292 Chevy inline 6 engines pumping irrigation water. They would be fired up for the growing season and would run 6-8 weeks at around 2500 rpms, around the clock, with no services. Some of the engines had glass sight tubes attached to the oil pan to gauge the amount of oil in the pan when running and we would add when necessary. No shutting down and servicing. That would be 1680 miles a day, if it was going 70 mph. 11760 miles per week. 70560 miles in 6 weeks. We used oil out of a 55 gal drum and transferred it to an easier carried container to add oil to the engines.

 

[GMGuy]

We don't do anything special with our fleet at work. Change the oil when the OLM indicates and carry on.

Alex.