A Cummins winter front is a cover that fits over the grille of a Ram 2500 or 3500 diesel and cuts down the bitter air crossing the radiator and the charge air cooler, so the engine can hold its temperature and the cab gets heat. Below 0°C, Ram's answer is yes: the 2026 Ram 2500 and 3500 owner's manual (Canadian edition) says a winter front or cold weather cover is to be used in that cold, especially during extended idling. If you want one before the deep cold, our parts department can order a Cummins winter front for you.
The same manual says the cover's four flaps should be left fully open so air still reaches the charge air cooler and the automatic transmission oil cooler, and that all four need to be closed once the temperature drops below minus 17°C. Our advice for any cover is to watch the temperature gauge. If the needle climbs above where it normally sits, open the flaps or take the cover off, and if it still reads high, book a cooling system check with our service team.
Key Takeaways
- Ram's manual answers the question. The 2026 Ram 2500 and 3500 owner's manual (Canadian edition) says a winter front or cold weather cover is to be used below 0°C, especially during extended idling.
- Flaps open until minus 17°C. The manual keeps all four flaps fully open in ordinary cold and has them closed below minus 17°C.
- It earns its place on short trips, long idles and an empty highway at minus 30, where a lightly loaded diesel struggles to make and keep heat.
- Our advice: open it up or take it off for a thaw above 0°C, before towing a heavy load, and any time the gauge reads higher than normal.
- A gas Ram 1500 owner goes by the Ram 1500 owner's manual. The winter front instructions quoted here are written for the Cummins.
- Our parts department can order one, so ask about timing before the cold settles in.
What a Cummins Winter Front Does
Behind the grille of a Ram heavy duty diesel sit the parts that shed heat into the air: the radiator, the charge air cooler that cools the air coming off the turbocharger, and the automatic transmission oil cooler. Ram's manual names the last two in its winter front instructions. At minus 30, air pushing through that stack at highway speed can pull heat away faster than a lightly loaded diesel makes it.
A winter front closes off part or all of that opening. With less frigid air crossing the radiator, the coolant can reach and hold its normal temperature, and there is heat left over for the cab and the defroster.
Ram's 2026 manual also warns that long periods of idling can damage the engine, because combustion chamber temperatures can drop low enough that the fuel is not completely burned.
What Ram's 2026 Owner's Manual Says
The instructions sit in the cold weather pages of the 2026 Ram 2500 and 3500 owner's manual (Canadian edition). In plain terms, the manual says:
- a winter front or cold weather cover is to be used when the outside temperature is below 0°C, especially during extended idling;
- the cover has four flaps for managing how much of the grille is open as the temperature changes;
- when a cover is used, the flaps should be left in the full open position so air reaches the charge air cooler and the automatic transmission oil cooler;
- when the temperature drops below minus 17°C, the four flaps need to be closed;
- a suitable cold weather cover is available from your Mopar dealer.
Those are Ram's temperatures, not ours. For an earlier model year, check the cold weather section of your own owner's manual.
When a Winter Front Earns Its Place
Short trips. A few kilometres to town and back at minus 25 rarely gives a diesel time to warm up, and with the grille wide open the needle can barely move before you park. If the heater still blows lukewarm with a cover on and the gauge at its normal spot, the cause may be elsewhere; our post on a truck heater not blowing hot walks through the four usual suspects.
Long idles. Sitting beside an ice fishing shack on Lake Manitoba or at a winter job site with the engine running is the case Ram's manual singles out. The manual also tells owners to avoid prolonged idling, so shut down when you can. Our post on whether to warm up a diesel engine in the cold covers how long to idle before you drive.
The empty highway at minus 30. Picture a lightly loaded truck at 100 km/h on the Trans-Canada Highway between Portage la Prairie and Brandon in ice fog at minus 30, with wind forcing through the grille the whole way. That is where a cover's flaps do their work, set open or closed by the manual's temperatures.
Open the Flaps or Take It Off
Ram's numbers say when to run a cover. Our advice on when to back it off comes down to the temperature gauge.
When the weather turns. The manual's line is 0°C. A thaw above that takes away the reason the manual gives for a cover, so take it off for the warm spell and put it back when the cold returns.
Before towing heavy. The manual keeps the flaps open so air reaches the charge air cooler and the transmission oil cooler, and a loaded stock trailer or a gooseneck full of bales makes both work harder. Open the flaps or remove the cover before you hook up, and keep an eye on the gauge into a prairie headwind.
Any rise on the gauge. If the needle climbs above its normal spot, open the flaps or take the cover off as soon as you can safely stop. If it keeps reading high with the grille open, the cover was not the cause and the cooling system needs a look. Our service department does cooling system service and repair, and diagnosis; book a temperature gauge diagnosis and tell our team the outside temperature, the load and whether the cover was on.
Mopar Cover or an Aftermarket One
Ram's manual describes a cover with four flaps and says a suitable cold weather cover is available from your Mopar dealer. Aftermarket covers can differ in how they attach and in how much of the grille they let you open. Whichever you buy, our advice is to choose one you can manage the way the manual describes, with flaps that open fully for ordinary winter driving and close completely below minus 17°C, used the way your vehicle's manufacturer directs.
Cummins winter fronts can be ordered through our parts department. It is an order item rather than a shelf item, so ask our parts team about timing and have your truck's model year ready when you call.
Does a Gas Ram 1500 Need One?
The winter front instructions quoted here sit in the diesel engine pages of the 2026 Ram 2500 and 3500 owner's manual (Canadian edition), so they are not a Ram 1500 instruction, or one for a gas Ram 2500 or 3500. If you drive a gas half ton, go by the cold weather section of your Ram 1500 owner's manual before covering the grille, and ask our parts department what is offered for your truck. Whatever the engine, if the gauge climbs with a cover on, open it up.
Plug In Before You Cover Up
A winter front helps a running engine hold its heat; it is not a cold start tool. For that, the 2026 Ram 2500 and 3500 owner's manual (Canadian edition) describes the Cummins engine block heater, a resistance heater in the engine's water jacket that plugs into a 110 to 115 volt AC outlet with a grounded three wire extension cord. The manual notes the cord is a factory installed option and is available from a Mopar dealer if your truck does not have one.
Plug in before a cold start, the way your vehicle's manufacturer directs; our block heater guide for Manitoba covers how long to plug in. Our service department installs block heaters.
Winter Fronts and Cooling Checks in Manitoba
At Dunn Ram Trucks in Portage la Prairie, the parts department orders the cover and the service department handles cooling system work and block heater installs. If your diesel needs more than a cover this winter and you are weighing a newer truck, you can see what your current truck is worth and apply for financing online. Any approval, rate or term is on approved credit.
FAQs
Does a Ram Cummins need a winter front?
Below 0°C, Ram says yes. The 2026 Ram 2500 and 3500 owner's manual (Canadian edition) says a winter front or cold weather cover is to be used when the outside temperature is below 0°C, especially during extended idling, with the cover's four flaps left fully open until it drops below minus 17°C.
When do I close the flaps on a winter front?
Below minus 17°C. The 2026 Ram 2500 and 3500 owner's manual (Canadian edition) says the four flaps need to be closed when the outside temperature drops below minus 17°C, and that above that they should be left fully open so air reaches the charge air cooler and the automatic transmission oil cooler.
When should I take a winter front off?
Take it off once the weather is back above 0°C, the point below which the 2026 Ram 2500 and 3500 owner's manual (Canadian edition) calls for one. Our advice is also to open the flaps or remove the cover before towing a heavy load, and any time the temperature gauge reads higher than normal.
What if the temperature gauge climbs with the winter front on?
Open the flaps or take the cover off as soon as you can safely stop. If the gauge still reads higher than normal with the grille open, have the cooling system checked; our service department does cooling system service and repair, and diagnosis.
Does a gas Ram 1500 need a winter front?
Ram's winter front instructions in this article are for the Cummins, from the diesel engine pages of the 2026 Ram 2500 and 3500 owner's manual (Canadian edition), not for the Ram 1500. A gas Ram 1500 owner should go by the Ram 1500 owner's manual before covering the grille, and can ask our parts department what is offered for that truck.
Can I get a Cummins winter front through Dunn Ram Trucks?
Our parts department can order a Cummins winter front for you. It is an order item, so ask our parts team about timing and have your truck's model year ready when you call.
The Bottom Line
A Cummins winter front is Ram's own answer for a diesel below 0°C, especially one that idles: flaps open in ordinary cold, all four closed below minus 17°C. Take it off for a thaw, open it up before a heavy tow, and let the temperature gauge have the final say.
If you want a cover on the truck before the deep cold, ask our parts department to order a Cummins winter front and have your model year handy.
Tyler Dunn, Dunn Ram Trucks, Portage la Prairie
