Jus wondering how cold does it have to get for diesel to start geling up? reason im asking is the lows are getting into the 30's.I need to know what I need to do to my truck for cold weather.It has a block heater on it so ive been plugging it in at night fore I go to bed. Thanks

 

I'd also like some cold weather tips, still a noobie here in the diesel world!

 

A lot has to do with where you live. Northern climates will have #1 fuel mixed in with the #2 at the pump to lower the gel point in the diesel. You should be fine in the 30's, regardless of which fuel you have.

If you want to be on the safe side, there are several fuel additives out there that help reduce the gel point even further. Diesel Kleen in the white bottle, Howes, etc.

Something else you may consider. Invest in a timer for your extension cord. Set it to come on 2 - 3 hours before you plan to leave. No need to waste electricity all night.

 

This was stolen from another thread at another site but I copied it because this question comes up every year about this time. (Thanks to Cool_Canuck - TDS)



Cycling the glow plugs. This does nothing except help wear out your GPR. Your glow plugs will stay on well after the “Wait to Start” light goes out.

The batteries need to be good. If the batteries are older than 4 years, they are near the end of their useful life. Even if the truck seems to turn over good, poor batteries will not have enough power to keep the glow plugs hot and supply the power to operate the injectors.

The glow plug system needs to be in good operating condition. There are plenty of threads that address this.

Fuel needs to be a winter blend. Buying fuel for the slip tank in Texas and trying to run on it in Saskatchewan in January won't get you out of the driveway. If it gets unusually cold, some anti-gel additive will add some insurance. Winter fuel will give you about 20 percent less energy so you mileage will suffer big time in the winter around here.

Oil needs to be as or better than recommended in the diesel supplement chart. The recommend 10W30 dino will work most for most areas. That chart is base on dino oils and you may prefer a synthetic with a larger viscosity spread. Just ensure that it meets or exceeds the specifications. A lot of folks have gone to 5W40 Rotella for year round use.

A 1,000 watt block heater is standard equipment on 99-04 7.3s. If you haven't found the cord, it's tied up under the by the left tow hook. I do not get concerned with plugging in the block heater until the temperature starts dropping to -20C (0F). Ford says that three hours of operation is sufficient and some folks use a timer as not to waste energy. However, if it is -30C and the wind is howling, three hours won't do much.

The transmission is also temperature sensitive and plugging in the block heater isn't going to help it. It will not shift out of second gear until it is damn good and ready. It will not lockup either. In fact, mine, once it does lockup will unlock once the thermo valve opens the cooler line and that slug of cold oil hits the transmission. At least, I think that is what is happening.

What's that noise? One of two things and probably both. If it's coming from under the hood, it's the engine cooling fan. The engine fan's thermo coupling is suffering from “morning sickness” (Ford's term, not mine) and is more noticeable in cold weather. This will quieten down in a few minutes as the silicates or what ever they are, get back to where ever they belong.

If it's coming from the tail pipe and sounds like someone has stuffed a potato up there, it's the Exhaust Back Pressure Valve (EBV). This valve closes in a cold engine to create a load which will help the engine warm up a little quicker.

RPM increases. In the cold weather and the vehicle believes it has been parked for 90 seconds to 2 minutes the computer will increase the engine rpm. I understand the standard transmission equipped need the park brake set for this to kick in. How much increase depends on the ambient temperature and barometric pressure. My truck will idle up from 700 to 1300 rpm. You will notice that engine temperature has no bearing. The reason for the rpm increase is to prevent a condition called “wet stacking”. A diesel engine produces little heat while idling. Sucking in cold air doesn't help matters. The combustion chambers don't get hot enough and a sticky deposit remains on valves, valve stems and guides eventually causing engine damage. At least that's the story. I doubt you will find case of it actually happening to a 7.3 on this forum. Maybe it works.

Blue smoke happens. My truck will start with the blue smoke just above freezing temps and get worse as the temperature plummets. Down around -30C the neighbors' houses start to disappear. If you let the vehicle idle, it will last a long time and if you drive off it will clear up quickly.

This is the way I do it in the cold (see cold above).
This truck is my daily drive and it's parked exposed in the driveway.

I turn the key on and wait 15 - 30 seconds or so. The colder it is, the longer I'll wait. The wait to start light is just another computer generated idiot light. The glow plugs stay powered up well after that lite goes out. Up to 2 minutes. If it has been plugged in, I will use that time to unplug the truck and do what ever with the extension cord.

The truck usually starts right up. May rock, roll and rattle a bit, but it starts. If yours get the romps, change oil. My truck will start cold soaked at -30C unaided with 10W30 dino oil. Done that on more than one occasion. And why not? Ford's manual says it will.

I don't let it idle any longer than it takes me to clean the ice and snow off the windows. Won't be going anywhere fast. The drive train is stiff as all get out and it going to take some power to move it. Letting it sit and idle in the driveway isn't going to help that. If it is really cold and stiff, I plan my route down residential streets so I can keep the rpm down to around 1,700 until I see the temp gage coming up and then keep it under 2,000 rpm until it is up in the operating range. With the engine working somewhat hard, it doesn't take very long. A mile or so.

This diesel has been better in the cold than any gasser I have owned. Starts better and warms up quicker.

Just a reminder – If you do a lot of stop and go driving and the engine doesn't get up to and stay at operating temperatures for a good length of time, it is considered severe service duty. You need to change oil more frequently.