Do you let your TV warm up before towing?
Reason I ask, left campground last Sat. around 11:30 am. Outside temps were about mid 50's. I didn't wait for the truck to warm up. When you leave the campground you turn on a two lane hwy. No way to ...
Forum Discussion
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I haven't had a diesel very long, only about 1 1/2 years, so I have some to learn yet. I do have some diesel experience with locomotives.
My diesel runs ok when cold but does seem a bit sluggish at increased idle. I'm not sure because I will never willingly work a cold motor hard, either gas or diesel. The sluggishness may come from poor cold burning and a resultant half dead turbo, since the turbo needs very hot expanding gas to operate. Otherwise the diesels may be sensitive to cold noise in particular because (I'm just guessing) they probably use forged pistons. Forged pistons expand a lot when hot, compared to cast, so they are always, always fitted loosely and this accounts for some of the excess noise (and blowby) until warm-up. And, thick, heavy pistons take a long time to warm up. Also consider that diesels have larger diameter bearing journals, so a large cold shaft shrinks up looser than the small diameter crank journals of gassers. They can't be fitted too tight, so cold clearances are greater until warm-up.
That said, I did have to start my 2000 7.3L Ford last winter, but I picked a reasonable day at about +10°F. Since I didn't plan on starting it in the winter, I had 15W40 oil in it yet and no 110v engine pre-heater. It took off after about the third try, using no ether, and apparently ran on about 4 cylinders for about 10-15 seconds. THAT was noisy. I did leave it idle for about 2-3 minutes before driving it. It turns out the oil cooler orings leak when it is that cold, and the sob leaked in my driveway. Initially the leak appeared to come from the oil filter, but no, the cooler is directly above that and the oil seems to follow the tilted filter gasket and run down the side of the filter. I found out that type 7.3 leak is common in this cold country. During warmer weather the oil cooler is just fine (for the moment).
I don't believe there is any problem in driving a cold motor, just not hard for a bit. I think some of the old wives tale about diesel warm up comes from the military, where reckless young operators like to gun the engines. There the preference is to indoctrinate them with a false sense of diesels "need to be idled"(warmed), as it is less harmful to idle excessively than overspeed a cold motor. There is logical truth in the saying, "the right way, the wrong way and the army way".
I consider allowing a long warm-up as intrinsically bad for any motor, especially carburated gas, because of overly rich idle mixes, and early diesels because of essentially the same thing which causes "wet-stacking", a load-up of unburned fuel. In both cases the unburned fuel ends up in the crankcase or out the tailpipe, both bad. Newer injected engines have much better combustion chambers and fine, high-pressure spray, fuel control systems and run cleaner, hot or cold.
There is another reason, besides the stink of cold warm-up, that begs no cold idle time and that is the reason I had to winter-start my diesel to begin with... to tow my dead gasser. I also have a gas V-10 Excursion just for foul winter driving. Last winter it was left locked and idling after I drove a few blocks to price a new start motor for same. When I came out of NAPA, the Ex was warmer and smoothly idling without oil pressure. Whoa! More noise (lifters) than a diesel!
I ended up with a new engine because, after running with no lube, I couldn't trust the old OHC engine out of town anymore. After making a decision to re-power it, I started it in case it regained oil pressure to make delivery to the Ford dealer easier. It DID have cold oil pressure and sounded as good as it did before it failed. I did not warm it up, but drove it immediately about 8 blocks to the Ford dealer, so I don't know if the oil pressure would have again dropped to zilch when warm, but it no longer mattered.
I have no idea why the idling V-10 engine failed, but here is my theory. When cold, the oil pressure by-pass (pop-off) limit valve likely opens (like all of them) to keep line pressure around 30#'s because of sluggish, thick oil. Either there was some debris in the oil pan that lodged in this valve (the oil pump is pre-filter), or the valve stuck wide open for some other reason when the oil warmed and thinned to normal. This could happen to any cold, running, unattended gas engine at any time. It's best to be driving where one can shut down if necessary. With the old 7.3L Ford diesel, I presume the engine would shut itself down when oil failed to feed the high pressure oil pump. No oil, no fuel. Newer diesels may not fair as well unless they have built-in safeguards.
Someone mentioned not shutting a hot diesel down immediately and I will bet this is still true of any old or modern turbo'd truck engine. The reasoning is that the turbo may be red hot and this heat will be conducted to the bearing shaft. Since the main reason the oil is pressure fed to this shaft is because its main job is cooling, no oil flow means that the oil will be cooked onto the bearing surfaces. It's called coking because the solid residue is much like coked coal which is used like charcoal in steel blast furnaces. This was not a major problem in old locomotives because an electric oil pump is left running for a timed period after shut-down... unless the operator is too IQ challenged to avoid this well-marked electrical breaker. Newer locomotives have automatic fool-proof controls because some people are that IQ challenged. Pick-ups, and many commercial trucks, do not have any provision for oil circulation after shutdown, just the operators IQ about shutting off super-hot engines.
Wes
...
I haven't had a diesel very long, only about 1 1/2 years, so I have some to learn yet. I do have some diesel experience with locomotives.
My diesel runs ok when cold but does seem a bit sluggish at increased idle. I'm not sure because I will never willingly work a cold motor hard, either gas or diesel. The sluggishness may come from poor cold burning and a resultant half dead turbo, since the turbo needs very hot expanding gas to operate. Otherwise the diesels may be sensitive to cold noise in particular because (I'm just guessing) they probably use forged pistons. Forged pistons expand a lot when hot, compared to cast, so they are always, always fitted loosely and this accounts for some of the excess noise (and blowby) until warm-up. And, thick, heavy pistons take a long time to warm up. Also consider that diesels have larger diameter bearing journals, so a large cold shaft shrinks up looser than the small diameter crank journals of gassers. They can't be fitted too tight, so cold clearances are greater until warm-up.
That said, I did have to start my 2000 7.3L Ford last winter, but I picked a reasonable day at about +10°F. Since I didn't plan on starting it in the winter, I had 15W40 oil in it yet and no 110v engine pre-heater. It took off after about the third try, using no ether, and apparently ran on about 4 cylinders for about 10-15 seconds. THAT was noisy. I did leave it idle for about 2-3 minutes before driving it. It turns out the oil cooler orings leak when it is that cold, and the sob leaked in my driveway. Initially the leak appeared to come from the oil filter, but no, the cooler is directly above that and the oil seems to follow the tilted filter gasket and run down the side of the filter. I found out that type 7.3 leak is common in this cold country. During warmer weather the oil cooler is just fine (for the moment).
I don't believe there is any problem in driving a cold motor, just not hard for a bit. I think some of the old wives tale about diesel warm up comes from the military, where reckless young operators like to gun the engines. There the preference is to indoctrinate them with a false sense of diesels "need to be idled"(warmed), as it is less harmful to idle excessively than overspeed a cold motor. There is logical truth in the saying, "the right way, the wrong way and the army way".
I consider allowing a long warm-up as intrinsically bad for any motor, especially carburated gas, because of overly rich idle mixes, and early diesels because of essentially the same thing which causes "wet-stacking", a load-up of unburned fuel. In both cases the unburned fuel ends up in the crankcase or out the tailpipe, both bad. Newer injected engines have much better combustion chambers and fine, high-pressure spray, fuel control systems and run cleaner, hot or cold.
There is another reason, besides the stink of cold warm-up, that begs no cold idle time and that is the reason I had to winter-start my diesel to begin with... to tow my dead gasser. I also have a gas V-10 Excursion just for foul winter driving. Last winter it was left locked and idling after I drove a few blocks to price a new start motor for same. When I came out of NAPA, the Ex was warmer and smoothly idling without oil pressure. Whoa! More noise (lifters) than a diesel!
I ended up with a new engine because, after running with no lube, I couldn't trust the old OHC engine out of town anymore. After making a decision to re-power it, I started it in case it regained oil pressure to make delivery to the Ford dealer easier. It DID have cold oil pressure and sounded as good as it did before it failed. I did not warm it up, but drove it immediately about 8 blocks to the Ford dealer, so I don't know if the oil pressure would have again dropped to zilch when warm, but it no longer mattered.
I have no idea why the idling V-10 engine failed, but here is my theory. When cold, the oil pressure by-pass (pop-off) limit valve likely opens (like all of them) to keep line pressure around 30#'s because of sluggish, thick oil. Either there was some debris in the oil pan that lodged in this valve (the oil pump is pre-filter), or the valve stuck wide open for some other reason when the oil warmed and thinned to normal. This could happen to any cold, running, unattended gas engine at any time. It's best to be driving where one can shut down if necessary. With the old 7.3L Ford diesel, I presume the engine would shut itself down when oil failed to feed the high pressure oil pump. No oil, no fuel. Newer diesels may not fair as well unless they have built-in safeguards.
Someone mentioned not shutting a hot diesel down immediately and I will bet this is still true of any old or modern turbo'd truck engine. The reasoning is that the turbo may be red hot and this heat will be conducted to the bearing shaft. Since the main reason the oil is pressure fed to this shaft is because its main job is cooling, no oil flow means that the oil will be cooked onto the bearing surfaces. It's called coking because the solid residue is much like coked coal which is used like charcoal in steel blast furnaces. This was not a major problem in old locomotives because an electric oil pump is left running for a timed period after shut-down... unless the operator is too IQ challenged to avoid this well-marked electrical breaker. Newer locomotives have automatic fool-proof controls because some people are that IQ challenged. Pick-ups, and many commercial trucks, do not have any provision for oil circulation after shutdown, just the operators IQ about shutting off super-hot engines.
Wes
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