DEF Hydrometer

[philc]

If I was to drain my DEF tank and refill it with fresh DEF is there anything I need to be concerned about such as getting air in the system. I would much rather discard any leftover DEF fluid before winter storage and fill it with some fresh fluid in the spring. The price of DEF fluid is minimal compared to trouble on the road.

Phil 

[wildebill308]

Phil, I can't afford a coach new enough to use DEF so I don't have any experience with the system. From the diagrams it looks fairly straightforward. I will bet it will turn out to be a best practice to drain the system before a long storage period. The only question is do you have a drain on the DEF tank? Can you install one?

Bill 

 

[philc]

Bill

I haven't checked for a drain but the tank is very accessible and the fill cap is right on top of the tank so I would just siphon it out.

Phil

[wildebill308]

59 minutes ago, Philc said:

Bill

I haven't checked for a drain but the tank is very accessible and the fill cap is right on top of the tank so I would just siphon it out.

Phil

Hopefully there is some way to drain it. When you are done siphoning it out you might try using a wet vac to suck the last bit so the tank is clean with no residue in it.  The good news you can wash out the wet vac when you are done in a well ventilated area.

Bill

[jleamont]

Phil, if it were me I would fill it before storing, when you start the season, drain it and refill it. That way no condensation forms in the tank and with DEF when it contacts air it crystalizes and you DONT want that in your tank. When I say "fill it" I mean to the recommended level, there needs to be room for expansion due to it freezing if you are in a cold climate. I would suggest purchasing a DEF hydrometer and test it in the spring, you might only have to drain half out and top it off, they are not expensive, just make sure you don't get any DEF on the paint and rinse the hydrometer after use.

here is one that is cost effective;

http://www.tooltopia.com/thexton-108.aspx?utm_source=google&utm_medium=cpc&utm_campaign=paid_search_google_pla&scid=scplpTHX108&sc_intid=THX108&gclid=CMC79ZmL-dICFQaBswodQxcOIg

[philc]

Jleamont I already purchased a hydrometer. In two weeks when I uncover the MH I'll test and evaluate the quality of the DEF. Your thoughts on winter storage makes sense to me,my tank is 3/4 full now so ill make sure I do the same at the end of the season.These engines are so sensitive that any little thing I can do to try and prevent a problem is worth it to me.

Phil

[hermanmullins]

Wouldn't it be easier to take a reading when putting the coach to sleep for the winter and when awakening in the spring. If it doesn't meet the requirements then change it. If it does meet the specs then add fresh and crank it up. What harm might be done if all the DEF is drained and there is a bit of residue left? Wouldn't the fresh dilute the small amount without any problems? 

Just a thought from a guy with a non DEF engine. (400 ISL)

Herman 

[jleamont]

Herman, that would be an option to test before and after storage. The other part of storing it low or empty is a dangerous gamble, here is why I wouldn't do it; if the DEF is low the tank will condensate and what remaining DEF will Crystalize and dry up, there is a DEF tank filter in the bottom of the tank that requires maintenance (we change them annually, in a coach every other year would be a good practice) these are cheap from the dealer and simple to change if you can access the top of the tank. DEF is like concrete when it dries, not to say more on top wouldn't break it down but not worth the risk for $15.00 in DEF. here is what it looks like in 36 hours.

 

[philc]

I'm learning something everyday. I had no idea there is a filter on the DEF tank. I'll have to call Cummins and get a part number and keep one on hand. Thanks to everyone for your input.

Phil

[jleamont]

Philc, what chassis do you have? Often the DEF tank is supplied by the chassis manufacture. If Freightliner call them for the part number.

[philc]

Jleamont it's a Freightliner chassis. I have to stop at the Freightliner dealer to pick up all the other filters I'll have them look it up. 

[hermanmullins]

Joe,

So if I read you right, it would be best to top off your DEF tank before storing and testing it afterwords. God I'm thankful for my 400 ISL.

Herman

[jleamont]

14 minutes ago, hermanmullins said:

Joe,

So if I read you right, it would be best to top off your DEF tank before storing and testing it afterwords. God I'm thankful for my 400 ISL.

Herman

Correct, that is how I would do it based off what we have experienced at work. I'm with you SO glad I don't have it....

[jrock]

Seams like the wizards of tree hugging that designed these systems didn't consider seasonal use vehicles that sometimes sit for mounts at a time. Maybe caterpillar was on to something with the system that didn't use Def if they only found a way to prefect it.

[jleamont]

John, you are correct, they also don't consider vehicles that don't run the highways often enough to build heat i.e. Emergency Vehicles and Utility vehicles, that will tend to be sitting at an elevated idle for a portion of the day, making a mess of the new emissions systems. Those tend to breakdown more frequently.

They (all diesels) started without DEF, then the Govt stepped up the game in the next tier of requirements. I will say the engines with it run better than the ones without it (Pre DEF years, not pre emissions years). Makes you wonder where the future is headed.