Ditching the fan shroud....driven on the highway and all, don't seem to have any overheating issues....what are potential problems with not having one?
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Fan Shroud Q
- Thread starter PKP80
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semlin
curmudgeon
overheating?
- Thread starter
- #3
corrected....2.5 hr drive on the freeway...nothing out of the ordinary.
PKP80 said:what are potential problems with not having one?
Almost guaranteed overheating when idling for an extended period after a drive. For example, sitting in heavy city traffic or a drive-thru after a jaunt down the freeway. You, my friend, are playing with fire.
Why for you do this?
Curtis
- Thread starter
- #5
CJF said:
spacing issues with body lift...thought i'd give it a try
MoJ
Moderator
PKP80 said:Ditching the fan shroud....driven on the highway and all, don't seem to have any overheating issues....what are potential problems with not having one?
You are aware of the dead spot on the oem temp gauge right....
https://forum.ih8mud.com/showthread.php?t=64252
i.e. you could be running a hell of a lot hotter than you were before removing the shroud and not know it by looking at the gauge.
NorCalDoug
problems solved daily...
I considered doing this just a couple hours ago...when my damned fan shroud didn't want to slide into place. 
I got it to work, finally...but did consider ditching it for a few minutes.
I took a good look at how it's shaped and what it's supposed to do -- if you look closely you'll notice that it's designed to create sort of an airlock to help pull air through the radiator.
given all the heating issues that people have experienced and reported, I think it'd be better to have one than not.
just out of curiosity -- what issues could you have with the shroud? it basically connects to the radiator. whatever probs you might have with the shroud, you'd also have with the radiator...no?
I got it to work, finally...but did consider ditching it for a few minutes.
I took a good look at how it's shaped and what it's supposed to do -- if you look closely you'll notice that it's designed to create sort of an airlock to help pull air through the radiator.
given all the heating issues that people have experienced and reported, I think it'd be better to have one than not.
just out of curiosity -- what issues could you have with the shroud? it basically connects to the radiator. whatever probs you might have with the shroud, you'd also have with the radiator...no?
NorCalDoug said:I considered doing this just a couple hours ago...when my damned fan shroud didn't want to slide into place.
I got it to work, finally...but did consider ditching it for a few minutes.
I took a good look at how it's shaped and what it's supposed to do -- if you look closely you'll notice that it's designed to create sort of an airlock to help pull air through the radiator.
given all the heating issues that people have experienced and reported, I think it'd be better to have one than not.
just out of curiosity -- what issues could you have with the shroud? it basically connects to the radiator. whatever probs you might have with the shroud, you'd also have with the radiator...no?
My issues with it are fan/shroud interference with the supercharger installed. Since I haven't had the time to work with it in quite some time, I have run shroudless since February. IMO/E so far, I see no need for it. Over 45mph it becomes a barrier to free airflow thru the radiator anyhow.
I admit to completely ignoring the multiple warnings here of impending doom over my cut blade fan, multiple radiator core clip and welds, and missing shroud. After my last 4 months of towing experiences, I'm pretty convinced too that the 80 has a very good cooling system, and the shroud is most likely for increased A/C efficiency when driving at low speeds.
My question comes from a different perspective... Is it excessive/obsessive focus on sub 100C temps causing increased cylinder wall wear, causing increased fuel consumption, oil blowby and higher temps? I'm intrigued too, how popular these trucks are in hot climes (a lot of 80's get bought here and shipped to SA), and there doesn't seem to be a massive demand for more cooling.
Scott Justusson
Shroudless, Snipped, Supercharged
semlin
curmudgeon
they don't have the same head gasket issues in OZ. one theory is that the EGR system, which they don't have, increases engine temps in the 1fz.
the 80 is meant to run under 100 celsius or it would not have an 82 celsius t-stat. My 80 has no special cooling mods on it but will still run well under 100 celsius 8 months of the year and even in summer only goes that high in unusual conditions when I'm climbing hills, usually in conjunction with the AC on. The AC shut off is 108 celsius so I very much doubt they designed a vehicle with only 8 degrees of safe operating range.
the 80 is meant to run under 100 celsius or it would not have an 82 celsius t-stat. My 80 has no special cooling mods on it but will still run well under 100 celsius 8 months of the year and even in summer only goes that high in unusual conditions when I'm climbing hills, usually in conjunction with the AC on. The AC shut off is 108 celsius so I very much doubt they designed a vehicle with only 8 degrees of safe operating range.
semlin said:
The EGR system could be an issue, but there are a lot of trucks that are purchased in the US and sent abroad.
I'm not sure water temps is absolutely tied to optimal engine operating temps. It might be exactly the opposite in terms of sizing the thermostat to give the largest safe range. If you go to post #19 in the Consolidated Operating Temperature Thread, you can certainly see how 100C temps are optimal in terms of wear and fuel consumption. If you look at 180 temps (82C) the cylinder wear is almost twice what it is at 210.
However, you can also see that the difference between 180 and 212 isn't massively significant in absolute number on this 60hour test. But remember too, if you aren't boiling off the moisture in the oil, you have more acid and sludge, and your oil additives are working harder vs the FJ80 that regularly sees 100C temps during it's driving cycles. My own opinion and experience is 100C is optimal, and that the "cooler is better" claims really depends on the definition of 'overheat'. My definition is boiling over of antifreeze or a blown head gasket. Those temps are in far excess of 225f.
Optimally, regularly exceeding 100C oil/engine temps is a good thing. Condensed water in the oil can not be separated any other way.
I for one, see absolutely no reason to run "cold" on the 80 engine. I'm also convinced that oil pressures will actually stay higher over time (since water in oil reduces it's viscosity index, and creates acid and sludge buildup). To compromise, I'd certainly say 82-108C Toyota targetted operating temps (180-226) are ok, but never exceeding 100 creates more problems than it solves. A 190 thermostat would probably do just fine for the 8 months where you never see 100C.
I claim you want to see 100C, and regularly.
Scott Justusson
- Thread starter
- #12
a lot of great info....thank you all for the help....I think I'm going to try no shroud for my trip up to Pismo this weekend which will have a few hill climbs, traffic, a/c on and off, a weighed truck, and some cruizzzing speeds....wish me luck and "cool runnings" or 100C runnings 
SUMOTOY said:
Not necessarly. The low level of moisture in oil will evaporate nearly as fast at 180f as 212f. We are not talking pure water her that will boil at 212f. The actual lubes function better at the 180-220f range, but not lower ranges.
cary said:
I don't agree, since water is vapor by definition at 100c (212), below that it's just hot water. We are talking about pure water from condensation that needs to be separated from oil, which is temp stable at 100C. This is the accepted theory of a vacuum heat oil dryer (PVC system) distillation process. Optimal target for oil viscosity then, would be at 100C, which is the definition of Viscosity Index.
We can look at lube function as optimal at 100C, and anything less is not optimal for wear or fuel consumption, since water content affects aeration and saturation and "Viscosity and thermal breakdown" of the oil itself.
I'm open for understanding a sub 100C temp, but there is a lot of documentation that supports 100C as optimal. The problem is, we have variables like ambient temp, engine/weight load, thermal efficiencies, thermostat cycling, wear and a myriad of other variables that make water thermostats less of a science and more of a range in application.
That doesn't change the physics of water in oil and the separation temps of it.
Scott Justusson
- Thread starter
- #16
Didn't have it when I ran the Rubicon, if that's any help for comparrison.
CJF said:
Cipped stock fan blade, clipped and soldered maybe 10 cores on the rad, no shroud, no aux fans, and only some mild ducting in front of the rad. Extremely clean radiator and cooling system, 50/50 greeen A/F (no magic additives), fresh mobil 1 synthetics in crankcase and trans. Supercharger running 6-7psi max.
No cooling issues at idle = A/C didn't cut off, but it wasn't super cool air coming out either (expected). I wasn't running 82C either.
My experience with cooling systems over the years makes me look at the monster 80 rad, and find it hard to believe there are cooling issues with it. Though I still plan on hood vent installs, since I'm pretty convinced the issues with the 80 are with trapped heat, not exchanged heat.
Scott Justusson
94 Supercharged
