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Discussion Starter #1
Hey everybody,
2021 Chevrolet 6.6L Duramax
Looking to buy some parts to keep in the truck for working on it if anything happens and for oil change... Need the following info
Oil Filter Wrench size
Oil Drain plug size
Lug nut size
Fuel Filter Wrench size

Also where do you drain the water from the separator on these? Im coming from three 5.9 Cummins so i'm new to the Duramax and working on it.
Thanks in advance!
 

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So for the oil filter, I use the 'big range' Lislie strap wrench (with a 1/2 drive ratchet) I got one of these when I had my Cummins for the (horrible to change) oil filter.

I believe the oil drain plug is 15 MM but I could be mistaken, if you plan on doing your own oil changes, definitely look at the Fumoto valve. I used this one, comes with the little clip to make sure the valve doesnt somehow open on it's own...

The fuel filter is now a 'cartridge' type element, so you have to unscrew the plastic housing to change the filter. I think the housing uses either a 32 or 36 MM socket, but I will need to go outside and check... You also drain the water from the bottom of that plastic housing, there is a small thumbscrew at the bottom of the housing to drain the water.

When you change the fuel filter, you have to prime the system, which is really tricky on these pushbutton start trucks. Basically you have to push the start button but not let the truck start. Make sure all the gauges do their full sweep, wait a few seconds, then push the button again to turn power off to everything. After the second or third time doing this you will hear the fuel hissing through the lines and the filter head.

To be safe I did the above procedure about 15 times until it didn't sound like too much air was going through the lines, and the truck started after about 5 seconds of cranking.
filter.JPG
 

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Discussion Starter #3
Thanks for the info, lol i'm going to get some tools together and the sizes you mentioned and get under there and start testing. Every time I think about it i'm in a hardware store or Home Depot and want to get all the tools I will need, then I come back out and forget all about it.
That oil drain plug is bad ass, and no trouble with it opening ever or vibrating loose and dumping oil?
And I went on the site and looked at all the different ones, any word why so many of the same style and thread?
 

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Since the filters are installed at the factory by a large angry gorilla and won’t break loose by hand, I used a large pair of channel lock pliers that worked well.

A filter cutter is handy to check for contaminates in the filter pleats and won’t further contaminate the filter like a grinder or hacksaw might. After draining, cut out the pleats and stretch them out. Every engine seems to produce small amounts of tiny glitter but something failing will make lots of metal. If a chunk with part numbers on it falls out and smashes your toe, you might have a serious concern...

After doing the first oil change and seeing how long it takes to drain the oil even when hot, I figured I wouldn’t have the patience waiting for it to drain from an even smaller hole in the Fumoto valve. It sure is a cool idea though. I’ll probably try it if I ever get tired of wiping oil off my shop floor.
 
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