In speaking with a cummins diesel tech working for DC about winter fronts (while he was programming my high idle, 3cyl mod.) he mentioned something I hadn't thought about, winter fronts of any sort were not recommended by DC at all as they tend to put a lot of extra stress on the fan clutch and could cause early failure. This being the reason they don't offer any.

For some reason it actually made sense to me. I've held off for now, even though its been all negative temps here for quite a while I can still maintain 180*(ish) engine temps on long (50+ mile) hauls with no trouble. Takes a bit to warm up in the evenings after work, but in the morning with the block heater I have no issues.

Anyone got any thoughts on the clutch notion?

 

If your need is for more heat do not block off all the rad, but leave a hole about 12" in the center of your front that way it will take a load off your fan hub!

 

I think it should be pointed out that a winter front that blocks off the grille openings is a completely different animal that a sheet of (whatever material) placed between the intercooler and the radiator.

 

Many of us have good luck taking the fan off each fall, and replacing when temps start approaching 80 of so in the spring.

 

First of all I don't agree with the Cummins tech as his physics are backwards, when a propeller has nothing to grab there is less stress than when it has full access to air water etc. The hole in the center of the winter fronts was to allow cold air to access the temperature control for the fan to make it think there is no need to engage from the additional heat in the rad one is trying to keep in the engine. Removing the fan is a good option up to a certain point if the truck stays moving while running, unfortunately my truck and some others here experience high working idle times in extreme cold. What happens here is the engine would be drawing 0 air and might overheat in the case of what we calll a chinook (-40-+5 overnight), instead I prefer to keep the front totally covered and be able to drop it by opening the hood and tucking my canvas winter front into the front bumper. The second theory here is you can't have uneven air accessing the cooling fan, this has some validity however even in the summer the fan has unequal air access due to the bumper and molding structures in front of the rad. The highest stress time for a rad fan is when at high temperatures the fan goes from almost idling to full lockup pressure. The rivets holding the steel fan together per blade cannot tell when stress is equal as per the whole blade or just passing through a lower air density area. Large trucks went to high flow plastic/nylon fan blades years ago to reduce weight on the bearing in the temp controlled hubs and reduce clutch wear when engaging and disengaging. All aerodynamic class 8 trucks have radiators that are partially obscured by moldings and bumpers with limited catastrophic failures to fan blades over millions of miles. At -40 grill inserts are virtually useless as air available to the fan comes from underneath the bumper and engine, all our equipment including ones with air to air coolers are covered. The incoming air through the intake system is so cold it is impossible to overheat the engine by covering the cooler completely, the sacred EGT numbers will show you this. At any temperature down to 0 F grill inserts or fan removal will help nicely but there is a point where it just is not enough. I prefer to have 900-1000 F EGT's (covered rads) vs cold combustion temps (unburned fuel/blue smoke) washing down my cylinder walls. Has any body tried to put an 03-04 plastic fan on a 2nd gen yet? PK

 

Anybody know how many CFM the stock Cummins fan is rated at? I have a high CFM electric that I bought for my other truck, but there are clearance issues there. I thought about mounting the electric on the Dodge and then I could just turn it off in the winter.

 

DO NOT USE ELECTRIC FANS! On stuff that tows heavy or works a lot. If you havent noticed, how many working vehicles have you seen with electric fans? I cant think of any. And reason is they cant pull the air like a clutch fan. I dont see where a winter front on the grill would harm the clutch fan but I do see where it would cause it to run a lot since the clutch would see hotter temps. Althought I cant really say, thus the reason I havent gotten one. I wont get one unless I think my radiator is in danger (which would have to be seriously cool temps! Or my truck just wont run right, being to cold. Or someone proves why you need one at all. I also dont know why the clutch would be in any danger of wearing out by cycling since the clutch action is just a viscous fliud.

 

Lets apply a second scenario here, the thermostat is closed the engine is nominal operating temp (175F) and you are rolling down the highway at 60mph at -20 F. You then start pulling a small but never the less working grade and the engine now is building some good heat, the T stat opens and slightly pre-warmed coolant 0 to +30 F coolant is dumped into the one piece block. I suspect that there may be some contraction of the components (parent bored engine block), I don't see the difference between this and putting 70F water a into a hot (210F) over heated engine in the summer which is claimed to do damage. Drop that to -40 and metal starts to react like glass under certain circumstances, at these temps I wear 4 sweat shirts or sweaters and my Helly Hanson coveralls. Why- because my core temp needs to be protected and so does my Hummin Cummins, obviously not everybody is using the CTD under these extreme conditions. Proven fact mechanical components used and maintained at a fairly consistant operating temperature live longer, achieving this may take some creativity. If your truck is under warranty it does not matter the glove box bible says they will fix it unless they can prove abuse. The flathead at warranty central has no comprehension of these situations as when he leaves work in his Command Start gasser his boss and the "book" are always right. Want to scare yourself put a temp guage on the lower rad hose and monitor what comes back from the engine year round. I still maintain every body here is always right because I dont own your truck and pay for it- what I have written has worked for me best part of 30 diesel years. PK