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Messages posted by: Dave
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For anyone who believes the old wive's tale that idling is good for your diesel engine, please hear me out. Idling is the worst condition for any engine, but especially for a diesel. Not only does it waste fuel, it acceleraters wear, comparable and maybe even worse than WOT! Would you let your Jeep sit out in the parking lot at WOT while you go inside to fetch a Coke?

I am third generation trucker in Michigan. Our family owns and operates a fleet of trucks (154,000 lb. gvw). My Granddad told me stories of lore where he carried tarps and a charcoal grill during winter months in case he got shut down in cold temps. Old mechanically fuel injection and poor fuel made in nearly impossible to start those beasts in sub-zero weather. It was common in dire situations to drape a tarp over the engine to create a tent, slide the charcoal grill (after it flamed out) under the oil pan to heat the engine, and with ether (breath of death) and hopefully still good batteries, the truck would start, so long as the fuel wasn't gelled. Ohya, he also carried extra fuel filters because once gelled, it was wax, couldn't be thawed and the filters were trash.

That was yesteryear. It was better to idle a truck during the winter because ones' livelyhood depended on it. Things have changed. Much higher injection pressures, electronic injection, better attention to winter fuel blends, etc. Now, starting a diesel in winter is much less a problem.

So how is idling harmfull?

Our fleet was a test bed for Detriot Diesel (we ran Series 60) while they did tests on fuel filtration. I had a chance to get to know Craig Morris (DDC Engineer). There had been numerous articles out in the trade magazines preaching the evils of idling. I asked him why. He explained that diesels are compression ignition. Diesel fuel combusts more efficiently at higher heat and pressures. At idle, there is little to no boost. Less compression, less heat, incomplete combustion. Incomplete combustion causes soot. Soot is abrasive. High idle engines typically show upper cylinder wear. Worst posible location, since that is where compression is highest. I have also talked to Cat Engineers who say the same. All that was before EGR. I don't have a clue how much more relevent this topic is to our EGR engines.

Bottom line. If you are concerned about longevity, shut it down rather than let it idle, even if for a minute. Unless, of course, you're not sure you can get it restarted.

I have been following the thermostat project on the L.O.S.T. forum. I wish I could reply there. It made me think that I owe this forum an update to my homemade inline 195* tstat. I have been running it for a few months now without any problems. At the same time, I removed the mech. fan and shroud, so I don't know how much of my gain to assign to either mod. My mileage is up between 2 and 3 mpg. Under ideal conditions and cruising around 60 mph, the gain is more than 3 mpg. Also, and this has to just be my imagination, but I swear the torque converter locks earlier (56-57 mph) and the trans holds gears better at low rpm and light pedal. It must be due to something else because I can't see where engine temp would have any affect on the trans. I do know that when up to temp the engine is quieter. We had some days here in Michigan where the temperature was in the high 80's. I got real nervous on one of those days while caught in stop and go traffic. The gauge never made to the straight up mark. So far so good.

Member but can't post due to failed ecm. Truly L.O.S.T. indeed, but faring well.
Doesn't the overdrive button do exactly that?
Now I'm having your dream. Is this healthy?
Or better yet, use the gear shifter button for dual shifting programs, one for normal cruising and engaged for trailering. Oh, the sun is shining and I'm drowsey in dream land.
At 60 mph I think we are in 5th gear and waiting for the TC to lock. I wonder why the TC can't lock at, say 20 mph? Is the auto trans unable to shift with the TC locked? I would love to convert the OD buton on the gear shifter to a TC lock/unlock switch. And of course to be able to reprogram shift/downshift points. I would desire that even more than the engine tune.
Thanks for the link. I would like to post on that forum, but I'm outside, looking in. I forgot my user name and password and can't create a new one because my email address is "already in use". And, I can't get any response from the moderator...oh well.

Ultimately, I think the OEM tstat mod would be the best way to go. My $30 mod seems to be working, and I'm sure I'm getting a significant mpg increase. I don't know how much yet due to little travel and too many variables. I will be taking a trip to my cottage (300 mile round trip) next week, which will be good for data.

Thanks again.
I think you are right. The t-stat fits pretty tight in the housing but is not sealed. I reinstalled, with just one 3/32 inch hole. The tempererature gauge is back to reading normal. When I work the engine, I can get the gauge to the half way mark. My goal was for a tick or two past half way. I am going to run it for a while and see what happens in warmer weather. Obviously the T-stat didn't need any holes, and maybe a tighter seal.
Thanks GDE,

I picked up another stat and will try drilling just one 1/8" hole, and install it tomorrow.

Once I get my mods done, I'll give you a call to set up an appointment for the flash. Does the no limit Ecotune offer any efficiency advantage over the regular Ecotune? I haven't decided if I want to change out the TC.


Does the ECU do anything to limit peak combustion temperature, say for instance, vary BOI or boost? I wonder if I am just beating my head against the wall.

Thanks for the help.
Ryan, thanks for the pics. It's hard to tell, but possibly there may be two thermostats inside the housing? The main and a smaller one for cabin etc. I still would like to get my hands on one and break it apart.

So get this, I installed the inline 195* t-stat in the upper radiator hose; and the temperature gauge went DOWN! It always ran one mark less than 12 o'clock, now it is 1 and 1/2 mark below. Everything seems to operate OK, but I got a decrease instead of an increase in temp. I can only think that I drilled too many holes in the t-stat flange. I drilled four 1/8 inch holes to allow some by-pass and to feed hot coolant to the t-stat. But if it was by-passing too much coolant, then the 195* stat should be ineffective, but why the lower temp? Maybe the pressure is over coming the spring, but why the lower temp? Is it because coolant is in the radiator longer due to decreased flow?

Also, I pulled the mechanical fan. BTW, once the shroud is lifted high enough to remove the fan, the shroud will come out; at least on my 05 model it did.

So now I am befuddled. I want a higher engine operating temperature, but don't know where to go from here.
I my area Flying J uses Marathon and blend #1 heavily. I prefer Sunoco and always opt for the premium (additional 2 or 3 cents). I also like Torco and Shell. Next on my list is Citgo and Crystal Flash although I get mixed results. I can't speak for your area, but the point is; I find it worth experimenting.
With the fan removed, does the shroud need to be reinsalled, other than to hold the AC and coolant line?

I am going to give the inline tstat a try. I will be using two diecast straight neck sb chevy tsat housings back to back (clam shell) for a low cost (+/- $30) unit. I'll have to machine a land into one of them to accept the 195* tstat. I'm trying to figure a way to introduce a small pressure gauge between the two stats to read pressure in the hose when temp is between 175* and 195*.
Has anyone had trouble with the provent icing up like my home made unit did? The other half of my considering the elephant hose, is it leaves an available port for propane injection???
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