Death of an Excursion
... I think my gasser 2000 Excursion may be done for, at about 115k on the odometer. Today I stopped at NAPA to check on cost and immediate availability of a new (not rebuilt) starter. For the f...
Forum Discussion
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Thanks, guys.
To clear up cam chain failure discussion here, cam chain tensioner failure on the two-valve will also make a racket from chain slap. My Ford installer told me that situation has even caused a hole in the front aluminum cover on occasion. (Cam phasers are an additional hydraulic control item on newer engines.)
The lost-tension slap, in turn, can slap against the firmly mounted upper guide and severely wear or break it. This would cause the nylon guide to be chewed up, the plastic bits being capable of temporarily plugging the oil sump suction until the next engine start where oil would again flow until re-plugging. It's like a vacuum cleaner plugging with a sock until it is shut off (the sock falls) and restarted, then likely re-plugging later again. This can happen because the split rear thrust washer (front piece) can fall off the crank after severe wear and cause lower oil pressure fed to the passenger side cam, which in turn, drops oil pressure on the hydraulic cam tensioner, allowing chain slap. I believe some of the videos I linked to earlier in this thread explain it better.
My guess as to my cause of the temporary total loss of oil pressure would be plastic debris plugging the sump, or most likely a piece of debris getting stuck in the oil pressure bypass valve (which was probably open after the cold start), possibly a piece of debris from a defective oil filter or nylon guide. Stuck debris (holding it open) in a pressure bypass valve (when cold) would leak pressure off horribly when the oil warmed up. On the other hand, I did run into several descriptions where Triton engines lost pressure at speed and quickly seized up as simple junk before the truck came to a stop. Maybe a failed oil pump, or total plug. Not something I would want, especially out of town.
Several techs mentioned that 125k was an average lifespan for this engine. The young dealer/installer stated that he has replaced several engines in this mileage catagory. Now that may be taken with a grain of salt since they may have been trying to downplay my bad luck. There is one thing that I have not resolved yet, and that is the actual possibilty of some minimal coolant getting into the crankcase. I've heard that Ethylene Glycol is deadly to bearings, but I'm not sure at what concentration. A small amount might be too much, perhaps on the order of sugar in gasoline.
If the Triton intake, or some other joint, can leak coolant into the crankcase, this may severely shorten the life of an engine. This means that periodic coolant changes need to be made on schedule to prevent internal corrosion and leaks. Ethylene Glycol should be changed, or at least tested for ph, every 3 years. By the work-order, I see an oring gasket was replaced on my water pump, but I assume the leak was external and very minor (not visible to me) at this point. Remember, the tech said there was coolant in the crankcase, but he did not blame any particular reason for it upon my questioning.
Since debris (the only reasonable explanation in this erratic on/off case IMO) is known to occasionally plug some oil galleries further down the line in these engines, it would certainly not be safe to drive until the engine is removed and entirely disassembled. In my case, a disassembled 100k+ engine would at least merit refreshing with new bearings etc. The outright cost of the new engine is $4373.33, and the possibly slightly lower cost(?) of "refreshing" has to be weighed against the cost of a pristine new engine assembly. Because of the preceeding logic and odds, the need for a replacement engine became a no-brainer before I even knew the cause of failure.
If a man did his own work, all this would be different, since labor accounted for nearly half this extensive repair bill. And, no, it wasn't easy to part with the cash. This made an unexpected severe dent in our moderate savings, but it was still cheaper to repair than replace, so we bit the bullet.
Because the engine still ran smooth right before removal, it is possible that someone in the service department could have swapped a different toasted block for the $900 core. While I doubt anyone would resell it as is, I do believe our V-10 engine was repairable since it still ran so great after the initial oil pressure failure at idle. In a way, I hope somebody did do this, as it seemed a waste to wantonly discard this particular old V-10 to the core pile.
EDIT 3/16/14
A recent conversation, with a mechanic with whom I went to high school, brought up a possibility of which I was unaware. He claims that the newer low zinc oils do not show up as milky with coolant in them. He refers to many GM vehicles that he had worked on where there was known coolant in the oil pan, but coolant was only evident upon draining them. There may be some merit to this as he is very experienced, perhaps 40 years in a shop. I find it hard to believe because an emulsion is an emulsion, and emulsions are always cloudy (milky) in my experience. Maybe I am wrong.
Wes
...
* This post was edited 02/27/14 01:58pm by Wes Tausend *
Thanks, guys.
To clear up cam chain failure discussion here, cam chain tensioner failure on the two-valve will also make a racket from chain slap. My Ford installer told me that situation has even caused a hole in the front aluminum cover on occasion. (Cam phasers are an additional hydraulic control item on newer engines.)
The lost-tension slap, in turn, can slap against the firmly mounted upper guide and severely wear or break it. This would cause the nylon guide to be chewed up, the plastic bits being capable of temporarily plugging the oil sump suction until the next engine start where oil would again flow until re-plugging. It's like a vacuum cleaner plugging with a sock until it is shut off (the sock falls) and restarted, then likely re-plugging later again. This can happen because the split rear thrust washer (front piece) can fall off the crank after severe wear and cause lower oil pressure fed to the passenger side cam, which in turn, drops oil pressure on the hydraulic cam tensioner, allowing chain slap. I believe some of the videos I linked to earlier in this thread explain it better.
My guess as to my cause of the temporary total loss of oil pressure would be plastic debris plugging the sump, or most likely a piece of debris getting stuck in the oil pressure bypass valve (which was probably open after the cold start), possibly a piece of debris from a defective oil filter or nylon guide. Stuck debris (holding it open) in a pressure bypass valve (when cold) would leak pressure off horribly when the oil warmed up. On the other hand, I did run into several descriptions where Triton engines lost pressure at speed and quickly seized up as simple junk before the truck came to a stop. Maybe a failed oil pump, or total plug. Not something I would want, especially out of town.
Several techs mentioned that 125k was an average lifespan for this engine. The young dealer/installer stated that he has replaced several engines in this mileage catagory. Now that may be taken with a grain of salt since they may have been trying to downplay my bad luck. There is one thing that I have not resolved yet, and that is the actual possibilty of some minimal coolant getting into the crankcase. I've heard that Ethylene Glycol is deadly to bearings, but I'm not sure at what concentration. A small amount might be too much, perhaps on the order of sugar in gasoline.
If the Triton intake, or some other joint, can leak coolant into the crankcase, this may severely shorten the life of an engine. This means that periodic coolant changes need to be made on schedule to prevent internal corrosion and leaks. Ethylene Glycol should be changed, or at least tested for ph, every 3 years. By the work-order, I see an oring gasket was replaced on my water pump, but I assume the leak was external and very minor (not visible to me) at this point. Remember, the tech said there was coolant in the crankcase, but he did not blame any particular reason for it upon my questioning.
Since debris (the only reasonable explanation in this erratic on/off case IMO) is known to occasionally plug some oil galleries further down the line in these engines, it would certainly not be safe to drive until the engine is removed and entirely disassembled. In my case, a disassembled 100k+ engine would at least merit refreshing with new bearings etc. The outright cost of the new engine is $4373.33, and the possibly slightly lower cost(?) of "refreshing" has to be weighed against the cost of a pristine new engine assembly. Because of the preceeding logic and odds, the need for a replacement engine became a no-brainer before I even knew the cause of failure.
If a man did his own work, all this would be different, since labor accounted for nearly half this extensive repair bill. And, no, it wasn't easy to part with the cash. This made an unexpected severe dent in our moderate savings, but it was still cheaper to repair than replace, so we bit the bullet.
Because the engine still ran smooth right before removal, it is possible that someone in the service department could have swapped a different toasted block for the $900 core. While I doubt anyone would resell it as is, I do believe our V-10 engine was repairable since it still ran so great after the initial oil pressure failure at idle. In a way, I hope somebody did do this, as it seemed a waste to wantonly discard this particular old V-10 to the core pile.
EDIT 3/16/14
A recent conversation, with a mechanic with whom I went to high school, brought up a possibility of which I was unaware. He claims that the newer low zinc oils do not show up as milky with coolant in them. He refers to many GM vehicles that he had worked on where there was known coolant in the oil pan, but coolant was only evident upon draining them. There may be some merit to this as he is very experienced, perhaps 40 years in a shop. I find it hard to believe because an emulsion is an emulsion, and emulsions are always cloudy (milky) in my experience. Maybe I am wrong.
Wes
...
* This post was edited 02/27/14 01:58pm by Wes Tausend *
