Duramax, warm up time

ktmrfs wrote:


I'll agree in general with the no more than 30 seconds warmup. Under reasonable weather. However at least some of the newer diesels WILL warm up when cold with a short idle time. My 2015 duramax with temps near 10F will start nice hot air to the cabin in 5 minutes from a cold start while idling. How?? well, one they bump the idle speed to around 1000rpm, second they run the turbo vanes to maximum backpressure. now the engine isn't just a air pump, it is actually needing to do some work. So, normally get in start and drive. when below about 20F I hit the remote start, let it run the 5 minutes or so it will do with the remote start, then get in and go. Oh, BTW GM is nice enough to also have the heated seats on while it is under remote start.

Wonderfull.

You'll get nice warm air in 5 minutes if you take off after starting also. Probably sooner since the load under way with moderate acceleration is still likely far more than the jury rig system the manufacturer uses to force the engine temps up... plus you are actually making headway towards your destination.

valhalla360 wrote:

wowens79 wrote:
OP here, The DPF is my concern, but I do pull the boat to the lake, or take the camper out at least once a month, and we run to ATL, or Birmingham regularly, so I do get on the highway.

About how often do they want to Regen? I've read it's determined by soot particles, but does that equate to 500-600 miles? 2000 miles?

I drive about 15000 miles a year.

No engine (gas or diesel) likes short runs but as long as it gets an occasional run long enough to get to full operating temp, it's not a big issue.

If you are taking the camper out once a month and doing a couple runs per month to Atlanta/Birmingham, that will satisfy the need to get it up to temp and regen.

As far as warm up when you start, anything more than 30 seconds is a waste. Diesel engines take so little fuel to idle that they will never warm up in the driveway. Best to get on the road and not stomp on the throttle for the first 5 minutes of driving. FYI: This is what the manufacturers recommend).

I'll agree in general with the no more than 30 seconds warmup. Under reasonable weather. However at least some of the newer diesels WILL warm up when cold with a short idle time. My 2015 duramax with temps near 10F will start nice hot air to the cabin in 5 minutes from a cold start while idling. How?? well, one they bump the idle speed to around 1000rpm, second they run the turbo vanes to maximum backpressure. now the engine isn't just a air pump, it is actually needing to do some work. So, normally get in start and drive. when below about 20F I hit the remote start, let it run the 5 minutes or so it will do with the remote start, then get in and go. Oh, BTW GM is nice enough to also have the heated seats on while it is under remote start.

Wonderfull.

wowens79 wrote:
OP here, The DPF is my concern, but I do pull the boat to the lake, or take the camper out at least once a month, and we run to ATL, or Birmingham regularly, so I do get on the highway.

About how often do they want to Regen? I've read it's determined by soot particles, but does that equate to 500-600 miles? 2000 miles?

I drive about 15000 miles a year.

No engine (gas or diesel) likes short runs but as long as it gets an occasional run long enough to get to full operating temp, it's not a big issue.

If you are taking the camper out once a month and doing a couple runs per month to Atlanta/Birmingham, that will satisfy the need to get it up to temp and regen.

As far as warm up when you start, anything more than 30 seconds is a waste. Diesel engines take so little fuel to idle that they will never warm up in the driveway. Best to get on the road and not stomp on the throttle for the first 5 minutes of driving. FYI: This is what the manufacturers recommend).

Short drives are hard on any vehicle, gas or diesel. But probably harder on a diesel. The only vehicles really well suited for short daily commutes are electric.

My 2012 DMAX was used daily for the long 1 1/2 mile trip to the office & back. I found that I was always going somewhere else most days so put some 20/30 mile trips on it at hwy speeds. I used my remote start most days to either cool or heat when needed.
Retired now.

wowens79 wrote:
I'm considering a 2015 Duramax that a friend is selling that is pristine and well maintained. He drives a lot, it already has 115,000 miles on it.

I on the other hand have a short commute only 6 miles each way. I keep reading that short runs are rough on the new diesels because they don't get up to temp. Would my short commute be to short to warm it up good?

I live south of Atlanta, so in the winter, it's not like it will be really cold in the mornings. Not sure if that really matters.

I have a 2012 6.7 Power Stroke and have a ~8 mile commute. No fuel dilution problems, no emissions problems, no DEF problem. My truck has 128k miles and not a single issue to date.

Having said that these trucks do require some highway miles from time to time.

This from the Duramax owner's manual, Page 1-3:

Special DPF Driver Messages
If the vehicle is used for numerous short trips or extended slow-speed operation, the engine computer may not be able to adequately heat up the exhaust system to clean the DPF effectively. The engine computer has been designed to continuously monitor the condition of the DPF. When the engine computer detects that the DPF is nearly full of particulates and that the vehicle is not being operated in a manner that would allow effective automatic DPF cleaning, the Driver In Brief Information Center will display the message CLEANING EXHAUST FILTER KEEP DRIVING UNTIL MESSAGE IS CLEARED.If the vehicle continues to be driven in a manner that prevents effective DPF cleaning, the DPF will become plugged with particulates. If this occurs, the engine computer will turn on the service engine soon light in the instrument cluster and the DIC will display the message ENGINE POWER IS REDUCED.See Diesel Particulate Filter on page 9-11 and Engine Power Messages on page 5-11

https://www.manualslib.com/manual/801892/Chevrolet-Gmc-2014-Duramax.html?page=7#manual

This from the Duramax User's Manual Page 1-1:

Initial Drive Information Transmission Cold Operation
When temperatures are very cold,the transmission will prevent certain operations to protect against damage. The information below shows shift range availability based on transmission oil temperature:All shift ranges available at 25°C ( 13°F) or above.2 (Second) and 3 (Third) shift ranges only at 35°C ( 31°F) to 25°C ( 13°F).2 (Second) shift range only at 35°C ( 31°F) or lower.Torque converter clutch operation will also be prevented when air or transmission oil temperatures are below certain levels.In Brief For areas where ambient temperatures are below 40°C( 40°F), use synthetic transmission fluid approved to Allison®Transmission specification TES-295. See Recommended Fluids and Lubricants on page 11-10 and Automatic Transmission Fluid on page 10-10.

FYI, I very seldom "warm up" my duly. If I do, it's to warm the cab in the coldest of weather so I won't freeze to pieces driving.

I've never experienced any issues with DPF. Quite frankly, I absolutely cannot tell when the DPF is cleaning itself.

With the highway driving you describe added to the mix the DPF shouldn't be a problem for you. Regen frequency is totally dependent upon soot loading and your driving conditions will determine the miles between regens. People doing a large amount of stop and go driving, especially with fairly hard acceleration on starts, often report regen events between 200 and 250 miles while under optimal conditions (the sweet spot while towing where exhaust heat is high enough that some soot reduction will occur at times between regens) you can go over 700 miles.

If you think of the older diesels and the conditions that caused visible "smoke" that is what you want to avoid when possible because the DPF is now capturing what used to go out the exhaust and that is what loads it more quickly. Diesels are always producing some particulate matter but some conditions greatly increase the level and will result in more frequent regens.

Several European nations have been looking seriously at particulate matter from the current crop of direct injected gas engines which do produce and emit quite a bit of particulate matter. It is likely that a GPF (gas particulate filter) may be in the future of future gas engines unless the electric era arrives prior to more regulations. The chrome exhausts on my Cadillac and Corvette require regular cleaning to remove the particulate buildup, it isn't nearly at the level of older diesels but it is readily apparent.

OP, all trucks tend to regen at different intervals. On average once per tank but some are twice per tank. Again recommend picking up a Edge CTS monitor for newer diesels. They are very handy and can even read/clear codes, check injector balance rates and most importantly monitor regen cycles.

wq93 wrote:
Some of us "armchair automotive engineers" own and operate DPF equipped diesels so we have lived with their requirements.

Exactly... Spot on