crushers said:
Yep, same head I drove to California and back with, having cooling problems all the way. All after I clogged the rad with mud and the fan clutch gave up and broke the head.
The motor still runs fine BTW
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Yep, same head I drove to California and back with, having cooling problems all the way. All after I clogged the rad with mud and the fan clutch gave up and broke the head.
The motor still runs fine BTW
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crushers said:
Over heating in diesels occurs due to three things:
First, basic principles.
Diesel engines work on compression rather than combustion. As the chamber is PERMANENTLY alight, the heat generated is far more than a petrol engine. Add the basically standard turbo to this and you see where i'm coming from.
One: Turbo strapped to the side of your diesel generates upto 800 degrees CELCIUS through the turbine housing that if not properly shielded adds to the ambient heat of your engine bay.
Two: Diesel/Petrol cooling systems are the same, ideally the diesel should have a four core radiator or better fan setup.
Three: If you flatten your foot in a diesel as I'm sure you are doing, the glowplugs go from "mild" to "WHITE HOT". This in turn increases the temperature of the combustion in the chamber and MARKEDLY increases cooling requirements. Diesels were never made to go fast. Lose a gear and pull the foot up a bit.
so i am sitting here in my flu induced, drug induced early morning state , trying to understand why you are pointing towards a difference.Greg_B said:
IF the clutch fan is working as it should i.e. activating when the need to cool is there (the engine is running hot) no matter what the circumstances that fan should kick in. the heat generated by the "pluged rad", " faullty water passeges in the block","over fueling" etc as long as the actual passages outside the core tubes are not plugged with mud, that fan should work exactly the same as the fixed unit. it is the heat that activates the fan, correct? no matter what creates the overheating that fan should be able to do it's job, pulling air through the rad.
i do not think a fixed fan "masks" problems other than the problem of a "auto fan" design that is not working properly. that clutch fan is not doing it's job which now has me wondering wether or not other overheating problems that occure might not be the fault of the clutch fan not engaging as it should. e.g. towing a trailer with the autos (3F, 12HT). if the clutch fan is doing a marginal job then this might explain why perfectly good 3F auto blew it's tranny pulling a tent trailer through BC on a hot day at normal highway speeds(one case example $6500 repair). that also might explain why the 12HT autos keep loosing their OD due to overheating (personally i have seen 4 cases of this). none of these trucks had shown any signs of off-road usage, no plugged cores stopping the airflow to the fan that should have kept the system cool...
now if the fix fan can "mask" problems then why not the clutch fan? it is supposed to work when the engine is overheating which in my personal case it did not. that example should be enough to cause doubt on the ability of a clutch fan design. comparing fixed fan with "auto fan", they should be exactly the same in their final results. they should be moving exactly the same amount of air, once the clutch fan is engaged the blade area is moving the identical amount of air as the fixed fan correct? (since the same plastic fan is used in both cases)(and the engine speed hence rotation of the fan will be the same) then the results "should" be the same should the engien be heating up or over heating. that is the whole purpose of the fan is to improve air flow through the rad...
hummm....
Quote: Over heating in diesels occurs due to three things:
First, basic principles.
Diesel engines work on compression rather than combustion. As the chamber is PERMANENTLY alight, the heat generated is far more than a petrol engine. Add the basically standard turbo to this and you see where i'm coming from.
---hummm, this is contrary to what i have been taught and told, a diesel runs cooler than a gasser.
One: Turbo strapped to the side of your diesel generates upto 800 degrees CELCIUS through the turbine housing that if not properly shielded adds to the ambient heat of your engine bay.
---vast amounts of airspace around this turbo setup, this isn't a diesel surf engine bay.
Two: Diesel/Petrol cooling systems are the same, ideally the diesel should have a four core radiator or better fan setup.
---factory rad setup for the diesel HZJ75
Three: If you flatten your foot in a diesel as I'm sure you are doing, the glowplugs go from "mild" to "WHITE HOT". This in turn increases the temperature of the combustion in the chamber and MARKEDLY increases cooling requirements. Diesels were never made to go fast. Lose a gear and pull the foot up a bit.
---EGTs will tell if you are driving the engine too hard, if the EGTs are sitting at 1000F then you are still well with in the safe fueling range. Diesels were never meant to lug, they have vast amounts of low end torque but the amount of heat generated by lugging a diesel far out does the heat generated at higher RPMs where the exhaust gasses can move freely. don't beleive me then take a steep hill in 5th at 2100 rpm (the engine is working hard, i.e. lugging) and then do the same hill again in 4th at higher rpms and watch the results on the pyro gauge. i do agree though that diesels shoudln't be pushed hard either...
;^)
cheers
First, basic principles.
Diesel engines work on compression rather than combustion. As the chamber is PERMANENTLY alight, the heat generated is far more than a petrol engine. Add the basically standard turbo to this and you see where i'm coming from.
---hummm, this is contrary to what i have been taught and told, a diesel runs cooler than a gasser.
One: Turbo strapped to the side of your diesel generates upto 800 degrees CELCIUS through the turbine housing that if not properly shielded adds to the ambient heat of your engine bay.
---vast amounts of airspace around this turbo setup, this isn't a diesel surf engine bay.
Two: Diesel/Petrol cooling systems are the same, ideally the diesel should have a four core radiator or better fan setup.
---factory rad setup for the diesel HZJ75
Three: If you flatten your foot in a diesel as I'm sure you are doing, the glowplugs go from "mild" to "WHITE HOT". This in turn increases the temperature of the combustion in the chamber and MARKEDLY increases cooling requirements. Diesels were never made to go fast. Lose a gear and pull the foot up a bit.
---EGTs will tell if you are driving the engine too hard, if the EGTs are sitting at 1000F then you are still well with in the safe fueling range. Diesels were never meant to lug, they have vast amounts of low end torque but the amount of heat generated by lugging a diesel far out does the heat generated at higher RPMs where the exhaust gasses can move freely. don't beleive me then take a steep hill in 5th at 2100 rpm (the engine is working hard, i.e. lugging) and then do the same hill again in 4th at higher rpms and watch the results on the pyro gauge. i do agree though that diesels shoudln't be pushed hard either...
;^)
cheers
crushers said:
It is true a diesel runs cooler than a gasser but the diesel heat is more localised.
I once had a infra red pic of a diesel and gasser of similar cc side by side and the diesel had "black" hotspots around the combustion chambers whereas the gasser was a more even shade of grey all over at operating temp.
This is why diesels are best kept warm or warmed more fully before driving.
Still,having said that the 1HZ radiator probably has a least 20% more volume over the 3F radiator
crushers said:
And perhaps with the combustion starting "in" the head with the IDI motors. The heat stress inside the head must be considerably more then DI engines. OF course, as Lowenbrau points out, the 3B head is very robust, in the sense it keeps on going, unlike the the 2LT in many situations. The 1HZ "seems" to be in the same class as the 3B afaict.
hth's
gb
Good morning Wayne.
Because saying you have exceeded the stock parameters and need to make adjustments (either design or driving style) is totally different then creating blanket statements that something is designed or engineered wrong because it is not working for you. There is a huge difference in those two perspectives, and can mis-inform the masses.
Yes, the clutch fan could as well in fact mask a cooling system fault. It can engage more then would be required if the cooling system is marginal and/or impaired for some reason.
I think if both your old HZJ75 and Goldboys BJ74 both have fully functional coolant systems, (each component is operating correctly to spec) and you are both hitting the redline…then you are loading/or have tweaked the engines output past the design point of the stock cooling system. There is nothing wrong with that if that is the load you choose to place on it, and good that both of you are adjusting components of the cooling system to cope with the increased load.
Or, as mentioned by an earlier poster…you could take your foot out of it.
I find conversations like this interesting, and try to resist digging my heels in, but rather adopt a questioning and curious mind, open to new information. Give me something to work with. At the end of the day, it is the knowledge that is important. To that end I have been doing some research to either confirm, or refute my earlier post. It has been an interesting and educational read. In no way can a few hours research by me be construed as by myself “becoming an expert”, so with that in mind…If anyone can add, expand or correct the information presented in a meaningful way, please do.
I hope others find this interesting too.
Your assumption that a clutch fan should work the same as a fixed fan and move the same volume of air is not correct. The clutch fan will not totally lock up; therefore, assuming the same blades on each...it will not move the same rate as a fixed fan. The entire engine thermal management system is designed with this slippage in mind, by people much more learned then I...usually with a pile of letters behind their last name. As a rule, high speed travel brings air through the radiator and engine bay already, and in many instances the fan simply is not needed, where as slow speed…stop and go…high load…hot days…etc can require more air flow and the fan will engage to draw the air through the radiator and engine bay (remember…this is general)
The entire cooling system (pressure system, closed reservoir system, coolant properties, pressure cap, thermostat, radiator, water pump, fan) is designed to maintain as optimum a temperature range as possible for the given engine and “normal” use, over a wide range of operating climates. Adjustments are made for given markets and climates, but the principles are the same. Again, all components of the cooling system, in stock tune, and fully functional are designed to work together. If one component is not functioning correctly then the systems effectiveness is compromised. This may not be noticed till the system is stressed. Also, when you go way past stock trim, or workload the system beyond design, you can exceed the systems designed capabilities.
Too large a cooling capacity can adversely affect engine life and performance. Engine oil, the lifeblood, needs to be at its correct temperature to protect the best (apparently above 190F). The quicker a system can get up to operating temperature, the better it is for the engine. Anything that interferes with this is not good. Thus; closed systems, a thermostat that stays closed allowing a quicker warm up, and some sort of fan system that is designed to create limited air movement when it is not needed…and create more air movement when it is needed.
I wonder if a solid fan, in the middle of winter, would create too much air movement through the engine bay, not allowing an engine to get to “optimum” operating temperature, this increasing engine wear and tear, and aging the oil quicker.
Clutch fans are designed to come on when more air movement is needed, and the closed coolant system can not keep up. When the air passing the clutch fan heats up enough, it does its magic and increases resistance…thus increases air flow. The reverse, as the air passing the clutch fan cools down. The amount of airflow the fane will create, and what is requried are engineered.
The clutch fan is part of the entire cooling system, and therefore needs regular maintenance/checking as well. This is something I have been negligent on, and will be changing.
Don’t misconstrue and assume I am singing praise of the clutch fan, however it has its place and has seemed to work well for many...for many years. It makes sense that fixed, electric and clutch types all have pros and cons, and applications.
Sorry if this seems basic, however it is good primer for me, and lays some foundation for discussion.
That is too funny Wayne. Maybe it is not working properly because the stock systems ability to manage the thermal load is being exceeded? Again, let me say…if the stock system (read each component in good repair) is working as it should, and the system is overheating…then there is too much load being placed on the system. The load must be reduced…or the system changed to cope with the load. Is there some other way I can word this for understanding?
Are you really making the statement that transmission failures are the result of an engineering decision to using functioning clutch fans? I know so very little about the magic inside auto transmissions, however talking about auto transmission failures and blaming them on the clutch fan system seems unreal. Give me your science and educate me...please. If I am wrong, it is an opportunity for me to learn…and I have been wrong many times before
Was the 3F that blew its transmission being driven beyond a stock system in good repairs ability to cool? What was the engine coolant temperature at the time? And what was the ATF temperature? Did the light come on and was missed? Had the transmission ever been overheated in its entire life and not serviced? What was maintenance like? Was the screen blocked? What about those A440’s behind those 12HT’s. Were they driven around the city in 4th, and the lockup placed at that point where it does not know what to do? Again, what is the driving and maintenance history? Are they losing their OD (torque converter lockup) due to this driving style, or is it a transmission lockup pressure fault? I don’t know, and I suggest there is a host of other issues to look at before such a broad and damning statement is made. Go to the 3FE list and search to your hearts content. There is lots of information on the A440, as well as Toyota’s other auto transmissions. Seems the best thing you can do for your auto transmission is add an external cooler like a tru-cooler, and a temperature gauge. It’s like a pyrometer for your diesel, and we all know how much you love singing a pyrometers praise. Drive to the pyrometer and your auto transmission temperature. Rodney’s Extreme Valvebody seems to have done well for Petra’s A440 so far too.
Again, I say:
Recognize if you are going to be on the outer edge of "normal designed parameters from the factory", and make the changes needed to keep the engine thermally efficient...
But don't blame it on the clutch fan...
Get better Wayne. Sick is not fun.
gb
crushers said:
Because saying you have exceeded the stock parameters and need to make adjustments (either design or driving style) is totally different then creating blanket statements that something is designed or engineered wrong because it is not working for you. There is a huge difference in those two perspectives, and can mis-inform the masses.
crushers said:
Yes, the clutch fan could as well in fact mask a cooling system fault. It can engage more then would be required if the cooling system is marginal and/or impaired for some reason.
I think if both your old HZJ75 and Goldboys BJ74 both have fully functional coolant systems, (each component is operating correctly to spec) and you are both hitting the redline…then you are loading/or have tweaked the engines output past the design point of the stock cooling system. There is nothing wrong with that if that is the load you choose to place on it, and good that both of you are adjusting components of the cooling system to cope with the increased load.
Or, as mentioned by an earlier poster…you could take your foot out of it.
I find conversations like this interesting, and try to resist digging my heels in, but rather adopt a questioning and curious mind, open to new information. Give me something to work with. At the end of the day, it is the knowledge that is important. To that end I have been doing some research to either confirm, or refute my earlier post. It has been an interesting and educational read. In no way can a few hours research by me be construed as by myself “becoming an expert”, so with that in mind…If anyone can add, expand or correct the information presented in a meaningful way, please do.
I hope others find this interesting too.
Your assumption that a clutch fan should work the same as a fixed fan and move the same volume of air is not correct. The clutch fan will not totally lock up; therefore, assuming the same blades on each...it will not move the same rate as a fixed fan. The entire engine thermal management system is designed with this slippage in mind, by people much more learned then I...usually with a pile of letters behind their last name. As a rule, high speed travel brings air through the radiator and engine bay already, and in many instances the fan simply is not needed, where as slow speed…stop and go…high load…hot days…etc can require more air flow and the fan will engage to draw the air through the radiator and engine bay (remember…this is general)
The entire cooling system (pressure system, closed reservoir system, coolant properties, pressure cap, thermostat, radiator, water pump, fan) is designed to maintain as optimum a temperature range as possible for the given engine and “normal” use, over a wide range of operating climates. Adjustments are made for given markets and climates, but the principles are the same. Again, all components of the cooling system, in stock tune, and fully functional are designed to work together. If one component is not functioning correctly then the systems effectiveness is compromised. This may not be noticed till the system is stressed. Also, when you go way past stock trim, or workload the system beyond design, you can exceed the systems designed capabilities.
Too large a cooling capacity can adversely affect engine life and performance. Engine oil, the lifeblood, needs to be at its correct temperature to protect the best (apparently above 190F). The quicker a system can get up to operating temperature, the better it is for the engine. Anything that interferes with this is not good. Thus; closed systems, a thermostat that stays closed allowing a quicker warm up, and some sort of fan system that is designed to create limited air movement when it is not needed…and create more air movement when it is needed.
I wonder if a solid fan, in the middle of winter, would create too much air movement through the engine bay, not allowing an engine to get to “optimum” operating temperature, this increasing engine wear and tear, and aging the oil quicker.
Clutch fans are designed to come on when more air movement is needed, and the closed coolant system can not keep up. When the air passing the clutch fan heats up enough, it does its magic and increases resistance…thus increases air flow. The reverse, as the air passing the clutch fan cools down. The amount of airflow the fane will create, and what is requried are engineered.
The clutch fan is part of the entire cooling system, and therefore needs regular maintenance/checking as well. This is something I have been negligent on, and will be changing.
Don’t misconstrue and assume I am singing praise of the clutch fan, however it has its place and has seemed to work well for many...for many years. It makes sense that fixed, electric and clutch types all have pros and cons, and applications.
Sorry if this seems basic, however it is good primer for me, and lays some foundation for discussion.
crushers said:
That is too funny Wayne. Maybe it is not working properly because the stock systems ability to manage the thermal load is being exceeded? Again, let me say…if the stock system (read each component in good repair) is working as it should, and the system is overheating…then there is too much load being placed on the system. The load must be reduced…or the system changed to cope with the load. Is there some other way I can word this for understanding?
crushers said:
Are you really making the statement that transmission failures are the result of an engineering decision to using functioning clutch fans? I know so very little about the magic inside auto transmissions, however talking about auto transmission failures and blaming them on the clutch fan system seems unreal. Give me your science and educate me...please. If I am wrong, it is an opportunity for me to learn…and I have been wrong many times before
Was the 3F that blew its transmission being driven beyond a stock system in good repairs ability to cool? What was the engine coolant temperature at the time? And what was the ATF temperature? Did the light come on and was missed? Had the transmission ever been overheated in its entire life and not serviced? What was maintenance like? Was the screen blocked? What about those A440’s behind those 12HT’s. Were they driven around the city in 4th, and the lockup placed at that point where it does not know what to do? Again, what is the driving and maintenance history? Are they losing their OD (torque converter lockup) due to this driving style, or is it a transmission lockup pressure fault? I don’t know, and I suggest there is a host of other issues to look at before such a broad and damning statement is made. Go to the 3FE list and search to your hearts content. There is lots of information on the A440, as well as Toyota’s other auto transmissions. Seems the best thing you can do for your auto transmission is add an external cooler like a tru-cooler, and a temperature gauge. It’s like a pyrometer for your diesel, and we all know how much you love singing a pyrometers praise. Drive to the pyrometer and your auto transmission temperature. Rodney’s Extreme Valvebody seems to have done well for Petra’s A440 so far too.
Again, I say:
Recognize if you are going to be on the outer edge of "normal designed parameters from the factory", and make the changes needed to keep the engine thermally efficient...
But don't blame it on the clutch fan...
Get better Wayne. Sick is not fun.
gb
so let me understand this, correct me if i am wrong but theroeticly you could disconnect your fan completely and drive at highway speeds?
if overheating is the enemy of the auto tranny then why is what i said so far fetched? if the fan is not drawing enough air through to cool the tranny fluid then that will lead to a melt down, no?
the 3FE in question was a bone stock unit of low milage and cared for by Stampede Toyota, the driver is a pussy footer on a vacation with his young family dragging a tent trailer behind them. it was not an overly hot day the tranny died outside of Canmore on his way back from BC.
i am sure i am missing something here. please enlighten me.
please do dig your heels in, sometimes this is the only way i can see the light...
yah, being sick sucks.
thanks
cheers
Wayne
if overheating is the enemy of the auto tranny then why is what i said so far fetched? if the fan is not drawing enough air through to cool the tranny fluid then that will lead to a melt down, no?
the 3FE in question was a bone stock unit of low milage and cared for by Stampede Toyota, the driver is a pussy footer on a vacation with his young family dragging a tent trailer behind them. it was not an overly hot day the tranny died outside of Canmore on his way back from BC.
i am sure i am missing something here. please enlighten me.
please do dig your heels in, sometimes this is the only way i can see the light...
yah, being sick sucks.
thanks
cheers
Wayne
actually i forgot to respond to this point, the HZJ75 always ran at the same temp winter or summer at any speed. it never showed any signs of not warming up to operating temp...Greg_B said:
afterall that is what the thermostate is there to do, open and close as the need arrises, the thermostate would have to be stuck open with the fan running to not reach operating temps... yes? no?
cheers
long thread . keeping apart the river crossng issue with no fanclutch .. on the highway at high speeds .. does not afect when you get more aire throught the rad that the engine ( fan ) speed . ?
keeping apart the river crossng issue with no fanclutch .. on the highway at high speeds .. does not afect when you get more aire throught the rad that the engine ( fan ) speed . ?
Greg B you have outdone yourself. I am in total agreeance with your long thread above.
The coolant system is designed to keep the engine at its optimum operating temperature rather than keeping it as cool as possible.
An engine's clearance tolerances between components is designed to be "right" at it operating temp.
Too hot and everything goes sloppy,too cool and everythings tight with increased wear.
I am also ccurious as to just how fast a fixed fan can suck air through.
Its theoretically possible but unlikely that at freeway speeds a fixed fan maybe an impediment to airflow.
For example if its in 5th gear and doing only 2200 rpm it maybe actually pulling air through slower than if the fan was free wheeling and rtelying on vehicle movement for airflow. Just a thought.
The coolant system is designed to keep the engine at its optimum operating temperature rather than keeping it as cool as possible.
An engine's clearance tolerances between components is designed to be "right" at it operating temp.
Too hot and everything goes sloppy,too cool and everythings tight with increased wear.
I am also ccurious as to just how fast a fixed fan can suck air through.
Its theoretically possible but unlikely that at freeway speeds a fixed fan maybe an impediment to airflow.
For example if its in 5th gear and doing only 2200 rpm it maybe actually pulling air through slower than if the fan was free wheeling and rtelying on vehicle movement for airflow. Just a thought.
hummm. first you and Greg say the fixed fan is masking a cooling problem and now you are saying it is possibly retarding the airflow at highway speeds. if the fan is retarding the airflow then how does it mask the problem?roscoFJ73 said:
it is the THERMOSTATE that keeps the engine at optimun temperature, the fan just helps the air flow. it amazes me that since the beginning of automotive history, the fixed fans on all different types of vehicles were able to help keep those engines alive for hundreds of thousands of miles...around the cities and on the highways .
to me it comes back to the KISS principle. oh and the fact i do not TRUST the clutch fan.
now there are a couple downsides to the fixed fan, one that was already mentioned, the noise. when you are def like me it makes no difference anyway. the other is the increased load on the engine at highway speeds, this load makes the engine have to work harder and this translates to an average increase of temperature of 100F at highways speeds according to the Pyro.
Wayne I was just musing that at some point the air flowing through the radiator from the vehicles speed may exceed the amount of air drawn through the fixed fan.crushers said:
Maybe this another reason the clutch fan switches off,as it cant supply cool air as fast as it is naturally draughted through,maybe, maybe not.
I guess it would depend on the pitch of the blades,rpm,ratio of fan speed to engine speeed ect ect.
In regard to the thermostat I was unaware that it keeps the engine at optimum temperature once its warmed up.
The coolant would have to be really cool exiting the radiator to close the thermo.
I also thought that most manufacturers have scrapped the fixed fan in favor of clutch or electrically operated jobs
I know you dont trust the clutch fan but you have only given me one antecdotal reason/excuse not to trust it
it is my understanding that the temp of the coolant will open or close the thermostate, a couple of degrees and the thermostate should be closing slightly thus reducing the flow from the rad...
i understand your question and i would love to know how much air is being moved by the fan at different speeds. you have a good point, if the fan actually does interfere with the air flow through the rad. in my mind, if it did slow the cooling ability of the rad then when the clutch fan was installed the air flow through the rad should have kept the temp down but the fixed fan kept the temp constant so this leads me to beleive it must be still assisting the air flow at highway speeds even in 5th.
sorry if i came across as an ass, i was just trying to understand your line of reasoning.
yes, i have only this one example to go by since this was the only time i tried to replace the fixed fan on the HZ on the suggestion by another cruiserhead in BC while i was there. otherwise i probably would have never seen the results of the test.
for me it was an eye opener, it would have been different if the results were not so blatant...
cheers and peace...
i understand your question and i would love to know how much air is being moved by the fan at different speeds. you have a good point, if the fan actually does interfere with the air flow through the rad. in my mind, if it did slow the cooling ability of the rad then when the clutch fan was installed the air flow through the rad should have kept the temp down but the fixed fan kept the temp constant so this leads me to beleive it must be still assisting the air flow at highway speeds even in 5th.
sorry if i came across as an ass, i was just trying to understand your line of reasoning.
yes, i have only this one example to go by since this was the only time i tried to replace the fixed fan on the HZ on the suggestion by another cruiserhead in BC while i was there. otherwise i probably would have never seen the results of the test.
for me it was an eye opener, it would have been different if the results were not so blatant...
cheers and peace...
crushers said:
Again, once more....
Perhaps you pushed that engine beyond the stock systems ability to deal with the heat load....extra fuel, propane, turbo...foot into it.
So, something had to change...
Either your foot out of it, or increase the cooling capacity.
It's got nothing to do with the clutch fan in the sense that it is designed inside a certain criteria.
However, with the fixed fan as you mentioned...there is an extra load on the entire system on the highway, flat driving...which translated into 100F more pyro temp. Interesting.
gb