Runs nice and dies in 20 min UPDATE UPDATE

   / Runs nice and dies in 20 min UPDATE UPDATE #131  
I spent some years as a mold maker for the injection molding biz. My molding room manager had a trick for increasing the cooling rate and shortening the time to cycle a mold. He'd turn the outlet valve down, closing the flow some forcing the water to say in the mold longer & cooling the mold more effectively. This (he contended) let the water (a phase change material) absorb more heat energy faster, because as he said water being a phase change material has a variable ability to take up energy. this ability changes dramatically as it takes on energy andchanged temperature. There are thermal regiems during which it takes up energy slowly and others where it does so rapidly. His contention was that if he kept the water in the mod just a wee skosh (pardon the highly technical terms) longer, it'd take up a lot more thermal energy and cool the mold more rapidly.
He was correct. the molds cooled faster and that let him run faster cycle times.

SOOOOOOOOOOO Logically allowing the coolant to stay in the heat exchanger a little longer will cause an uptick in energy transfer, improving cooling capacity for the benefit of the engine.
One of the challenges of Physics is to explain observed events while maintaining strict avoidance of fantasy entering the science. To do this it is counterproductive/confusing to introduce variables out of turn. Sure water is a phase change substance - most things are but is it changing phase here? Lets bypass this a minute. -- Heat transfer is a function of delta T. However a hot surface in contact with tap water can form bubbles even below the point of actually boiling. These are dissolved gases leaving the water. These bubbles, starting as an infinitismal discontinuity, act as nucleation sites for evaporation of water. So the bubbles are mostly gaseous water in the long run, having been started by a spec "impurity" of O2, N2, Cl, etc escaping from solution. These "specs" themselves have formed at surface discontinuities in the vessel containing the water. Everyone sees this happen as they bring tap water to a boil. The issue is that these micro and growing bubbles forming in the mold "vessel" get in the way of water touching the walls of the flowpath thru the mold. The gas layer is an insulator. Now consider the effect of turning down the outlet valve. The water, now under pressure does not form any, or as much, gaseous H20 layer adjacent to the heat source.

SOOO The "logic" of [allowing the coolant to stay in the heat exchanger a little longer will cause an uptick in energy transfer] is not logic but happenstance based not on time but on pressure.

As for a t stat improving cooling capacity it does not. The undeniable benefit the t stat offers is keeping the engine at a relatively constant temp regardless of the workload and the ambient temperature. It does this by sensing coolant temperature and adjusting flow restriction to warm it quickly to the design temp and then constantly react to hold it there. It opens further and further, increasing flowrate, as the cooling needs increase. This works beautifully while the system is working nominally to its design, usually a long time. But finally things degrade to where overheating occurs. Maybe the t-stat is bad and will no longer open to its full extent. Maybe the radiator is cruddy inside or out. Maybe the fan belt is slipping. Maybe the head gasket is allowing a little combustion gas into the coolant jacket. Maybe a whole combination of things; its an old system variously maintained and, now, has been overheated.

If the t stat is bad and you change it it will act normal again, overcoming all the other problems of degradation; either a fix or a "fix". If the tstat is good and you remove it you will get a "fix" with problems lurking, either above, at, or below the horizon. Problems will not be because the fluid is dwelling anywhere too briefly to transfer heat - transferring half as much heat 3 times as often is the kind of thing that would actually happen.
- What could upset this physical truth?; *)An already slipping fan belt exacerbated by the water pump requiring more power to pump more fluid, *)an internally restricted radiator core causing much of the fluid to cross the top tank to feed the core channels that most directly flow to feed the increased suction from the bottom exit hose to the pump, *)bubbles/microboiling in the violently flowing heated fluid as it traverses the suction hose and impeller and then onward into the engine they act as nucleation sites growing and insulating from optimum heat transfer, *) Etc.

It would take chapters in an appropriate textbook from authors much more knowledgeable and lucid than myself to skirt simplisms that so easily creep into things that seem simple. The best of them can do it like a Carl Sagan story. IVE talked to maybe a couple people like that in a lifetime. Its the easiest way to learn ... and learning is progress.

Im going to get on back to the thread. Have we solved Danicas engine fade yet?
 
   / Runs nice and dies in 20 min UPDATE UPDATE #132  
Just found this: TC29D stalling when hot

SOLUTION -
Drained fuel from tank. No water was seen in fuel in tank. Filled tank with 2 gallons of Methanol attached a rag to a stainless piece of 2.5 foot by 1/8 piece TIG wire and scrubbed the tank. There was a considerable amount of varnish and debris in the tank. This explains why the system would prime but when a suction was put on the tank it would suck the larger pieces of varnish into the 90 deg elbow on the bottom of the tank and clog it up.

Tractor is now running non stop.
 
   / Runs nice and dies in 20 min UPDATE UPDATE #133  
Danica,
It sounds exactly like a pleated element fuel filter closing up from the differential pressure across it caused by fuel flow. I know youve changed the filter but is it the only one. Will the fadeout manifest quickly if you run the engine under high load? Can you start it cool at the bottom of a good hill and use a gear that forces the engine to work hard for a minute or so all the way up? ... Or maybe use a small bushog to stir pondwater? ;)
 
   / Runs nice and dies in 20 min UPDATE UPDATE #134  
One of the challenges of Physics is to explain observed events while maintaining strict avoidance of fantasy entering the science. To do this it is counterproductive/confusing to introduce variables out of turn. Sure water is a phase change substance - most things are but is it changing phase here? Lets bypass this a minute. -- Heat transfer is a function of delta T. However a hot surface in contact with tap water can form bubbles even below the point of actually boiling. These are dissolved gases leaving the water. These bubbles, starting as an infinitismal discontinuity, act as nucleation sites for evaporation of water. So the bubbles are mostly gaseous water in the long run, having been started by a spec "impurity" of O2, N2, Cl, etc escaping from solution. These "specs" themselves have formed at surface discontinuities in the vessel containing the water. Everyone sees this happen as they bring tap water to a boil. The issue is that these micro and growing bubbles forming in the mold "vessel" get in the way of water touching the walls of the flowpath thru the mold. The gas layer is an insulator. Now consider the effect of turning down the outlet valve. The water, now under pressure does not form any, or as much, gaseous H20 layer adjacent to the heat source.

SOOO The "logic" of [allowing the coolant to stay in the heat exchanger a little longer will cause an uptick in energy transfer] is not logic but happenstance based not on time but on pressure.

As for a t stat improving cooling capacity it does not. The undeniable benefit the t stat offers is keeping the engine at a relatively constant temp regardless of the workload and the ambient temperature. It does this by sensing coolant temperature and adjusting flow restriction to warm it quickly to the design temp and then constantly react to hold it there. It opens further and further, increasing flowrate, as the cooling needs increase. This works beautifully while the system is working nominally to its design, usually a long time. But finally things degrade to where overheating occurs. Maybe the t-stat is bad and will no longer open to its full extent. Maybe the radiator is cruddy inside or out. Maybe the fan belt is slipping. Maybe the head gasket is allowing a little combustion gas into the coolant jacket. Maybe a whole combination of things; its an old system variously maintained and, now, has been overheated.

If the t stat is bad and you change it it will act normal again, overcoming all the other problems of degradation; either a fix or a "fix". If the tstat is good and you remove it you will get a "fix" with problems lurking, either above, at, or below the horizon. Problems will not be because the fluid is dwelling anywhere too briefly to transfer heat - transferring half as much heat 3 times as often is the kind of thing that would actually happen.
- What could upset this physical truth?; *)An already slipping fan belt exacerbated by the water pump requiring more power to pump more fluid, *)an internally restricted radiator core causing much of the fluid to cross the top tank to feed the core channels that most directly flow to feed the increased suction from the bottom exit hose to the pump, *)bubbles/microboiling in the violently flowing heated fluid as it traverses the suction hose and impeller and then onward into the engine they act as nucleation sites growing and insulating from optimum heat transfer, *) Etc.

It would take chapters in an appropriate textbook from authors much more knowledgeable and lucid than myself to skirt simplisms that so easily creep into things that seem simple. The best of them can do it like a Carl Sagan story. IVE talked to maybe a couple people like that in a lifetime. Its the easiest way to learn ... and learning is progress.

Im going to get on back to the thread. Have we solved Danicas engine fade yet?
Largely (possibly completely) correct the succinct version: no thermostat does not cause overheat.

Please all that have taken interest please remember, OP had taken a pretty good shot at the fuel system. And had noticed the machine ran until hitting normal range on the gauge (this is generally the opening of the thermostat), light usage was 20 minutes, under load was less.

I was only trying to eliminate a variable while she waited on fuel lines. Information is good if it is easy and low risk to get. It has been interesting to hear peoples opinions and the way things become "facts" to folks sometimes.

Best,

ed
 
   / Runs nice and dies in 20 min UPDATE UPDATE
  • Thread Starter
#135  
You can't even run long enough to get the temperature up so why worry about over temping at this point? Did you have an overheating problem before you had this issue? If you didn't, then I would focus on getting your machine running longer than 20 minutes.

I agree and am changing all fuel hoses this weekend. Already finished the returns and tested but no luck…
 
   / Runs nice and dies in 20 min UPDATE UPDATE #136  
If it hasn't been mentioned before, I would check your fuel for "diesel bugs". It's conceivable that corrosion in the injection pumps and injectors caused by these microbes could cause a temperature related shutdown.

 
   / Runs nice and dies in 20 min UPDATE UPDATE
  • Thread Starter
#137  
If it hasn't been mentioned before, I would check your fuel for "diesel bugs". It's conceivable that corrosion in the injection pumps and injectors caused by these microbes could cause a temperature

Wow, I hadn’t heard of this stuff but since I just replaced 4 fuel hoses, the fuel and air filters, blew lines with compressed air, cleaned rad screen and more. Fuel flow always fine like when it is dying down the stream out of filter is fine.

Any sense in just buying their other product which ‘cures’ this infestation without even checking would be cheaper and couldn’t hurt but now I’m resigned to sending tractor to dealer.
 
   / Runs nice and dies in 20 min UPDATE UPDATE
  • Thread Starter
#138  
Largely (possibly completely) correct the succinct version: no thermostat does not cause overheat.

Please all that have taken interest please remember, OP had taken a pretty good shot at the fuel system. And had noticed the machine ran until hitting normal range on the gauge (this is generally the opening of the thermostat), light usage was 20 minutes, under load was less.

I was only trying to eliminate a variable while she waited on fuel lines. Information is good if it is easy and low risk to get. It has been interesting to hear peoples opinions and the way things become "facts" to folks sometimes.

Best,

ed

Thanks Ed, I just changed the last of the four fuel lines (not from tank to sediment bowl because I cannot get to it) and no go. Same thing every time. I’ve burned thru 4 gallons of diesel doing these tests and am now at the end of the road. However, tomorrow I will flush radiator and add new coolant/water 50/50 mix to see what happens. That will be Sunday. If that doesn’t work I’m going to pay the dealer fee to come get it and fix it then return it. The way I’m going replacing things I will have a new tractor in a few months! :)

Btw, has anyone ever had a regular old diesel mechanic (e.g., works on trucks) diagnose and fix their tractor?? I mean, I have an auto repair shop 2 miles away and they can get OEM parts as easily as I. Or are tractor diesels the sole domain of tractor repair (dealers) places? Just curious.
 
   / Runs nice and dies in 20 min UPDATE UPDATE
  • Thread Starter
#139  
I agree and am changing all fuel hoses this weekend. Already finished the returns and tested but no luck…

All hoses replaced and same issue. I never mentioned this because it seems so unrelated but I did put a new battery in tractor right when this started. Got the new battery in after it sat half full of fuel for 3 weeks with dead battery, installed new one and whammo—my problem began. Like I said I never mentioned it cuz it seems so irrelevant and the fact the tractor sat outside in 90 degree humid weather for 3 weeks seemed like a much more likely source of my problem. Note though I always use additives designed to avoid stale/bad fuel. I dunno.
 
   / Runs nice and dies in 20 min UPDATE UPDATE #140  
Wow, I hadn’t heard of this stuff but since I just replaced 4 fuel hoses, the fuel and air filters, blew lines with compressed air, cleaned rad screen and more. Fuel flow always fine like when it is dying down the stream out of filter is fine.

Any sense in just buying their other product which ‘cures’ this infestation without even checking would be cheaper and couldn’t hurt but now I’m resigned to sending tractor to dealer.

If you just dose your fuel with a biocide that will only kill the microbes, it will not remove the remaining algae, which will propagate new growth. Your fuel tank must be thoroughly cleaned, and then dosed with a biocide for at least three tankfuls. And never ever leave your tank less than 3/4 full ESPECIALLY during humid weather. If you have a bulk storage tank I recommend a vacuum/pressure cap - they are never freely open to the atmosphere. I recommend testing first.

We centrifuge all of our fuel. This is the centrifuge sludge tank full of dead bugs.

 

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