It's been a while since I changed the coolent in my '92. What is the best stuff to use? I would like somethin non toxic like Sierra or the like. Any suggestions?

 

Sierra and Long-Life (Dex-Cool) are not recommended for the Cummins. Cummins also recomends coolant changes every 24,000 miles to prevent cavitation. I use Zerex 5/100 mile coolant - the green stuff - and change it every 24,000 miles. Cummins has its own brand both in premixed and full strength. Zerex is made by Valvoline - as I believe - Cummins anti-freeze is. The premixed is a 50/50 mix with a freeze protection of -34 so if you want a stronger mixture you will need to mix it stronger. In addition I use distilled water for my &quot;mixer&quot; ;D ;D<br>Bob

 

Yeah, that's what I have in it now Zerex. I also use distilled water. I didn't know about the Serria but was thinkin about the ease of gettin rid of it. This stuff is pretty toxic. I live in southern Pa. It may get to -10 on a rare occation so the premix will work fine. Any suggestions as to filling so I don't get any air in the block?

 

I switched over to the Fleetguard ES Complete from Cummins (blue in color) it is the 50/50 pre mix and is supposed to be good up to 600k. Just be sure to flush the old green antifreeze out good before pouring it in, but a full radiator flush from a shop is not needed to convert, that is what Fleetguard told me anyway.