When did DEF become required ?

Most engine built after December 31 2009 require DEF BUT some manufactures bought extra 2009 engines so even a 2011 MH might have a 09 engine.

IIRC Jan. 2010

Mr. Dave, we bought the first year coach with the particulate filter on the 2007 chassis (2008 coach). We have had zero problems with it. DEF came out in 2010 if I'm not mistaken and our new coach will have it. I'm not concerned. The word on the street is the DEF units get a little better fuel mileage.

We have no smoke come out on heavy hill climbs. The regeneration cycle happens once about every 10,000 miles. There is a light on the dash to tell me the process is starting/happening.

If you want a totally emission-free diesel vehicle, go 2006 or earlier. It's funny, I remember when people were going crazy when the catalytic converters came out in 1975..... and fully implemented in '79-'80. Same happened with shoulder seat belts with the buzzers.

Go with the environmentally friendly units. Save a tree. LOL! (just kidding). Buy and drive what you like, this is America.

A side note: Before catalytic converters, the Los Angeles smog was horrendous. You couldn't see houses off the I-10 Freeway, especially, in San Bernardino, CA. There is still some smog but 95% better. Low emission vehicles are important for our health.
MM.

2006/2007 is the last model years for non-ULSD and non-DPF. The motors had to be made in 2006, but for some models (like my Fuso) they made all the 2007 model year motors in 2006. If you plan on going to Mexico or points further south, being able to take the non-ULSD becomes important.

Other than the ULSD issue in Mexico, the newer motors have some advantages. Dealing with DEF isn't really a big deal. Every so often you pour some in. It's fairly cheap, both in cost to purchase and in cost per mile. Heck, you already do that with windshield washer fluid.

I do not believe DEF was ever required. But, the engines had to meet the standards, and DEF is one of the ways it was done.

Just don't pour DEF in the fuel tank by accident like this guy did.

I was not in the market for my DP in 2007 until I went to an FMCA rally and attended a forum by the diesel manufacturers - Cummins, Detroit and Cat. As they said, at that time, they could not tell the long term effects of the new pollution-reduction requirements. So I took the plunge and bought my DP in May of 2007, but it had a 2006 Cummins engine. 2007 was the particulate filter requirements and 2010 came stricter requirements that were met by using DEF.

BurbMan wrote:
Just don't pour DEF in the fuel tank by accident like this guy did.

I just read all 10 pages of that thread (20 posts per page) and I will definitely be extra careful while putting DEF into the correct filler tube on our new coach. I know on the Prevost, they have moved the diesel and DEF fillers to the same opening so that both can be filled at the truck island. The DEF filler is just on the driver's side whereas the diesel filler is on both sides.

Mistakes can happen and it is apparently very expensive if you start the engine with DEF in the wrong tank. If not started (realizing a mistake was made), just removing the fuel, having the tank cleaned and refill with diesel will not damage the engine.

I have never noticed if the Diesel and DEF nozzles are different sizes to help against a brain burp. I know that the Diesel handles are green and the DEF's are blue.

MM.

Yes, but having a Prevost towed and the fuel tank drained, dropped, and cleaned, is not going to be cheap either....