Ok - Couple of questions for you long time diesel users here. I just traded up to a diesel - Cummins engine.I am uniformed and need some help before temps drop and winter arrives!1. Coach comes with an engine heater. How cold before I should plug it in? (Can't do when bookdocking!)2. Do you ever add an additive to keep diesel from gelling in cold weather? How cold does it have to get before it is a problem? I have been doing some reading but see no definitive answer - some say winter blends work and need nothing else. Some say below 25 add an additive. Makes me nervous - what do you do? (Note I will be wintering in AZ boondocking on the desert and not running much. Some nights do drop below freezing..............I want to be proactive!Heading from Florida through Texas and New Mexico in mid-November and know weather can get cold through there.) HELP!Seeking wisdom from you folks. Thanks in advance for your thoughts.

I turn the block heater on when it is around 30 degrees or starting to freeze. I did not turn it on one time when I was in Pecos, N.M and I had a slight problem starting the engine. Since then I turn the block heater on all the time and it fires up right away.

I use stabil diesel treatment in the winter, if my DP will be sitting all the time, in Chicago where the winters often include daily highs in the teens for weeks at a time.In Arizona, I don't think it would be a worry.I've never plugged in my engine heater in 5 years. We don't travel much in the winter, and again, we'd be talking lows below zero and highs below the twenty's before I'd use it. Our cummins always fires right up, tho when it's cold it takes 30 to 40 second for the wait to start light to go out.

Use up all of your Florida diesel before getting to colder temps. Truck brought in some product for our plant in the middle of winter. Had BIG saddle tanks with lots of Florida diesel, came up to Ontario with a load and his fuel gelled. We helped him by taking him to get some additive and adding that and putting heaters around the truck. Eventually a wrecker took the truck to a repair place , drained all the gelled fuel and sold him some nice new "northern " fuel. Several hundred dollars and more than a day later he off loaded and went on his way.All of this before I had a diesel truck. For what it is worth, the block heater cord on my 2006 was still curled up when I traded it in and I don't even know where the block heater cord is on the new truck! Always started fine in the cold.

I don't think you will have to worry much in Arizona. I would be surprised if they even sell winter (#1 or even 50/50 #1 #2 blend) in Arizona except for maybe in or around Flagstaff. With that being said I would carry some additive in the coach just incase a freak cold spell. I would not fill your diesel tank full of #1 just to be safe. I think it's a waste of money (costs more) and produces less energy resulting in a loss of MPG. Get the additive and only put in the tank if you're going to be in an area with sustained temps below 30 degrees or so. http://en.wikipedia.org/wiki/Winter_diesel_fuel

My Cummins doesn't much like anything below 40, so I just add stuff that the truckers use. Available at most any truck stop.

Winter and deisel use | Good Sam Community

19 Replies

roundown8366
Explorer
Sep 20, 2014
My cummins manual for an ISL400 shows around 10°f and lower an oil and coolant heater is suggested. Below -10°f is required.

Cold weather starting: the manual: follow normal starting procedures. The wait-to-start lamp will stay on longer.

This is straight from owners manual for ISC, ISC, ISL.

I have started my 400 with the sliverleaf reading 6° with no problem, oil pressure up within 3 to 4 seconds.
mrkoje
Explorer
Sep 20, 2014
Golden_HVAC wrote:

Usually the engines will start at 20F without the block plugged in, and will run normally after about 30 second warm up. At 0F or -10, then the block heater is more required, however winter blend has a bunch of unleaded gas in it, so it runs fairly well - even at 0F.

Fred.

Pretty sure winter diesel doesn't have gasoline mixed in. I know it has kerosene mixed in.
catkins
Explorer II
Sep 19, 2014
You guys are the best! Thanks for the info and the great article. Eases my mind a lot....... fear of what you do not know! Still lots to learn so I will likely be back with other questions.
RayChez
Explorer
Sep 19, 2014
DSDP Don wrote:
As I stated earlier, there was a temp that they recommend you should use your block heater to warm the engine. I did a search and found an article with some good info. It discusses temps, grid heaters and idling in the cold.

A question that often comes up is why does my volt meter drop to nothing and then come back several times when starting the engine. This article discusses the affects of the grid heater on battery voltage.

It's a good article for a newbie:

Cold Weather starting.

Great link Don. I agree completely with your article. Even the big puff of black smoke when it fired up. It happened to me in Pecos, N.M where the temperature had dropped to about zero. I did not plug in to shore power and let the coach just set for about a week at low temp. It wanted to start, but would run for a few seconds and then die. Until it fired up with a big puff of black smoke. I thought at first I had blown the engine up when it fired up. LOL! Since then I plug in when temperatures get that cold if there is shore power available. I have never added anything in the fuel tank, but your article about Karosene makes a lot of sense.
CA_Traveler
Explorer III
Sep 19, 2014
Doubtful you'll need to do anything in AZ snowbird areas vs the colder mountain areas.

I've never had a problem down to 20 degrees.
2oldman
Explorer II
Sep 19, 2014
DSDP Don wrote:
It's a good article for a newbie:Cold Weather starting.
That's a good read.

When my Cummins 8.3 battery voltage dropped to 11.3 before cranking the engine, I freaked. Then I learned about intake heaters, and how much she hates cold weather!
DSDP_Don
Explorer
Sep 19, 2014
As I stated earlier, there was a temp that they recommend you should use your block heater to warm the engine. I did a search and found an article with some good info. It discusses temps, grid heaters and idling in the cold.

A question that often comes up is why does my volt meter drop to nothing and then come back several times when starting the engine. This article discusses the affects of the grid heater on battery voltage.

It's a good article for a newbie:

Cold Weather starting.
charlie_good_ti
Explorer
Sep 19, 2014
I will add if a used rv you purchased make sure you have a new fuel filter installed.Old plugged filter with bacteria an other stuff will be more likely to be your problem if any on the trip you mentioned.Do carry a spare is a good idea too. If your Cummins has two filters i would let a experienced person change them for you.You dont want any dirt getting in none of them but especally the final one(one before the injection pump)
Ivylog
Explorer III
Sep 19, 2014
OP, it would help if you put this "FYI - my 2014 Tiffin Red" in your SIG. Your Cummins has a grid heater on the intake so once the "wait to start" light goes out it should start in any temp. Going E to W or W to E you do not need to add anything to your fuel. Going S to N and shutting it off could be a problem, but if you fill up with local winter fuel before shutting it off you will be fine.
Even when boondocking I can heat my engine off of my AquaHot, but unless it's below freezing I do not. You are worrying about this too much when in southern states.
TucsonJim
Explorer II
Sep 19, 2014
I'm from AZ, and my diesel truck doesn't have a block heater. Due to an ill relative last year, I had to head north in January and was exposed to the arctic vortex. Temperatures plunged to 15 below a couple nights. I added some diesel fuel anti gel that I picked up in a local parts store. I never had any problem starting or running the diesel engine after it had sat in the cold weather for 10-12 hours.

The additive I used is listed in this link, and it is supposed to work down to -40 when used IAW directions.

Diesel Fuel Supplement

In Arizona, I often see temps in the 20s and don't have any issue getting it started. I don't normally use additive in Arizona.

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Winter and deisel use

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