1 HZ Cooling Issues (1 Viewer)

Joined
Jan 21, 2010
Messages
245
Location
VT
After a complete rebuild and transplant of a 1 HZ into my 62, I am running into cooling issues. After transplant, it took me a good half year to rewire (I travel a lot and gone good portions of the year), and finally this summer have been able to drive. I have a Derrale high CFM dual fan, Painless dual fan control and OEM 62 radiator (8 years old) but I am not happy when I make the drive across a couple of passes around me. Temp in cylinder head stays between about 180-188 through most driving but on the passes gets up to 200, even to 210 once before I pulled over to help cool down.
I loved that my 3FE barely ever moved the stock dial, but I did not have a aftermarket temp gauge at the time.
About ready to pull out electric fans, build a shroud and go with mechanical fan. As I plan for a turbo in somewhat near future so I am wondering if the FJ62 radiator is the right one for the job and should I replace it before I go through making a shroud.
Thermostat is 4000miles old, from Toyota, coolant is all new.

Thoughts?
 
Joined
May 19, 2012
Messages
324
Location
Perth, Western Australia
that's what my 1HZ ran at with a turbo, 189 to 188f normally, and had it to 210f sitting on 68mph on a 113f day in north western Australia, the 1HD-FT I have now seems to run cooler at 167f to 185f.
 
Joined
Apr 26, 2007
Messages
4,943
Location
Dumont, CO
After a complete rebuild and transplant of a 1 HZ into my 62, I am running into cooling issues. After transplant, it took me a good half year to rewire (I travel a lot and gone good portions of the year), and finally this summer have been able to drive. I have a Derrale high CFM dual fan, Painless dual fan control and OEM 62 radiator (8 years old) but I am not happy when I make the drive across a couple of passes around me. Temp in cylinder head stays between about 180-188 through most driving but on the passes gets up to 200, even to 210 once before I pulled over to help cool down.
I loved that my 3FE barely ever moved the stock dial, but I did not have a aftermarket temp gauge at the time.
About ready to pull out electric fans, build a shroud and go with mechanical fan. As I plan for a turbo in somewhat near future so I am wondering if the FJ62 radiator is the right one for the job and should I replace it before I go through making a shroud.
Thermostat is 4000miles old, from Toyota, coolant is all new.

Thoughts?

It's an indirect injected diesel--they make a lot of heat on long hills. That's just a fact.

The Turbo will make this worse--it will get hotter on long hills, although hopefully you are taking less time going up those hills due to the turbo.

My suggestion would be to do anything you can to ditch the electric fan. Even the best electric fan will not compare to the mechanical fan. However, if that isn't a possibility (it hasn't been yet in my faux-lux) then you should make sure that your fan is coming on at least a little as early as possible. One of the problems with most electric fans is that they wait until the engine is hot before turning on at all, whereas the engine may never get that hot if the fans were pulling just a little air through the radiator from a much earlier starting point.

Have you cleaned, or rebuilt your stock radiator? I have ALWAYS rebuilt and recored the radiator when I swapped in a diesel. Has worked fine on the faux-lux (with stock 22RE radiator), 3B-T (with stock FJ-40 radiator), and 12H-T (with the stock HJ-61 radiator).

But at the end of the day, indirect injected turbo diesels get hot on long hills. I live right by some big, long hills. In the middle of the summer, I plan on stopping once or twice going up the pass to let the engine cool. Takes an extra couple of minutes, but then I can sit and enjoy the diesel clatter while I enjoy the scenery. No big deal, really.

Last note, when you go to add a turbo: don't use the coolant to cool the turbo (if that's an option). All that does, IMHO is heat the coolant a lot, which makes the problem worse. The turbo itself will cool once you stop making power. Only drawback is that you need to idle the engine before shutting it off to make sure the turbo has cooled down sufficiently before you shut it off. Usually a minute or two, if that.

Dan
 
Joined
Dec 31, 2013
Messages
39
Location
Arnhem, The Netherlands
I've sort off the same issue: a 1HZ in a FJ40. Running too hot on the high way beyond 70 miles per hour. I'm planning for a bigger free flow aluminium radiator replacing the 42! years old radiator. Also looking for a bigger fan. 1HZ is less economic than a 1HDT or 12HT and all that extra fuel becomes heat.
My radiator guy tells me the bigger radiator does the job. We will see.
 
Joined
Jun 10, 2007
Messages
5,424
Location
Kiwiland
Do you have a shroud on those fans? Without a shroud they are pretty much useless.

210F is not a problem. If you run a 15psi radiator cap then you won't boil until 120C (250F).
 
Joined
Jan 21, 2010
Messages
245
Location
VT
Thanks for the replies. I do have a shroud on the electric fans. I am really leaning toward going with a mechanical fan, building a shroud and either rebuilding the radiator.
Guess the only next question is weather a 3FE radiator is the best option or maybe there is a 1 HZ radiator that would be bigger. Any idea if some of the 1 HZ's radiators are bigger?
Also, work under the assumption that heat is what hurts engines. Is 210-220 bad for the engine over time?

Thanks
Sean
 
Joined
May 19, 2012
Messages
324
Location
Perth, Western Australia
according to my 1hz manual, the thermostat is fully open at 194f, and the cooling system capacity is 12 litres with a heater, 11 litres without. You could get the tanks taken off and get your radiator rodded to clean it properly, fit a standard fan and shroud, and see if it lowers the temp a bit.
 
Joined
Jul 22, 2003
Messages
18,131
Location
Perth Western Australia
Also, work under the assumption that heat is what hurts engines. Is 210-220 bad for the engine over time?

Thanks
Sean

You are not overheating with a coolant temp of 105C (220F). Is your system building pressure?
If the radiator cap or hoses are losing pressure somewhere ,it will always run hotter.
On the 3F engines in 7* series,the radiators have slightly smaller bottom tank than 1HZ models,but its only a litre or thereabouts.
An oil cooler on the engine would take some heat away
Big fluctuations in temperature are the worst thing for engines because everything is constantly expanding and contracting.
 
Joined
Jan 21, 2010
Messages
245
Location
VT
Since temperatures have cooled a bit here, I am running between 180F and 198F between normal driving and the same mountain pass. Thinking I will have the FJ62 radiator rebuilt this winter and go to a mechanical fan and custom shroud. The oil cooler is a great idea and I am going to look into the best way to do it.

Thanks for all the input.

S
 
Joined
Jan 21, 2010
Messages
245
Location
VT
Fairly convinced that the mechanical fan is the way to go but one thing I am thinking about with the current set up:
Temp sensor is in cylinder head but sensor for fan controller is in lower radiator hose. Wondering if difference in temperature between head and lower radiator could make the fans delayed if temperature in hose is below head. Any thoughts on that?thanks. Sean
 
Joined
Apr 26, 2007
Messages
4,943
Location
Dumont, CO
Fairly convinced that the mechanical fan is the way to go but one thing I am thinking about with the current set up:
Temp sensor is in cylinder head but sensor for fan controller is in lower radiator hose. Wondering if difference in temperature between head and lower radiator could make the fans delayed if temperature in hose is below head. Any thoughts on that?thanks. Sean

Does your fan controller have a set temperature? If so, then yes, that could make a difference. If the water coming out of the radiator is 182 degrees, then I shudder to think about how hot it must be going in.

But if you just have a generic thermostat, without an actual temperature measurement, then it doesn't make any difference. I have one of these on my faux lux. I just know that I have to set the knob so that the engine temp doesn't get too hot. I have absolutely no frame of reference for what that knob is "set" to, nor does it matter.

Dan
 

Users who are viewing this thread

Top Bottom