Hot on the Highway

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

SURVEYOR CRUISER

SURVEYOR CRUISER

10 Year 15 Year
Joined
Oct 23, 2006
Threads
19
Messages
85
So here is the scoop:
85 bj 70 3b with axt turbo, 9 psi boost
brand new 24"x19" 3 row double pass aluminum radiator with 16 lb cap
brand new toyota water pump
brand new thermo activated fan clutch
new hoses
new belt
new 82 degree celsius thermostat
new heater core.
autometer mechanical water temp gauge
autometer pyrometer with sensor mounted on exhaust below the wastegate.
KN air filter

Still the truck runs hot when pulling mountain passes at 50-60 miles per hour with the rpms at 2400

I am at a loss the truck hit 210 degrees farenheit on me and the thermostat equals about 180. at every other point than this situation it run at 160 degrees, 20 degree cooler than thermostat.

I do not lose any coolant or oil so I beleive the head and head gasket are fine. The EGT hits 1100-1200 degrees farenheit in the too hot situation. The only thing I can think of is it is getting too much fuel which is why it is getting too hot. I need help as I am stumped. Do I just need to slow down? You would think the truck could pull mountain passes at 50 mph Is it possible that the fan clutch is turning at high speeds and fighting the incoming air?
The only other thing I can think to do is turn the fuel down or get an electric fan as well.
Input is greatly appreciated.
:cheers:
 
too little fuel = hot (You've got your understanding backwards) Remember a fire burns hotter with the more air you add.

Is there ANYTHING blocking the rad? this happened with a friend and his winch cover was making him overheat on uphill runs with his trailer. He took it off and solved the problems of overheating. Perhaps a better rad/fan shroud is in order to redirect the air to the rad.
 
In front of the rad is my intercooler, not yet hooked up and my A/C condensor. No shroud yet. But I would not think this could matter at 70 mph. Also no chance the fan is fighting the air flow?
 
The 180 degree thermostat, only open at that temp allowing coolant to the rad, so it can be over if worked hard.

Does the stock gauge still work? What does it read? Could your autometer guage be reading wrong?

Air pockets maybe?? burb it on an incline, try a few things you have not already......
 
Sounds like you have done everything right. 210 F is 99C and not such a disaster.
Most engines have optimum operating temp of about 90C but you have to expect it to go up on long mountain passes.
Both my 1HZ non turbos will begin to climb in temperature if I go over 50 mph uphill and I probably dont have any climbs as long or as steep as you probably have.
 
SURVEYOR CRUISER said:
In front of the rad is my intercooler, not yet hooked up and my A/C condensor. ++++====>>No shroud yet.<<====++++ But I would not think this could matter at 70 mph. Also no chance the fan is fighting the air flow?
Click to expand...

It does need the fan shroud !!!
At this load the temp regulated fan kicks in and is ineffective if the shroud is not present.

Because the shroud is missing the fan is drawing the bulk of the air 'from the sides' so to speak, just pumping around the hot enginebay-air.
If the shroud is there the air, displaced by the fan, is forced to flow through the rad, coming from the front of the vehicle.
 
Last edited:
roscoFJ73 said:
Sounds like you have done everything right. 210 F is 99C and not such a disaster.
Most engines have optimum operating temp of about 90C but you have to expect it to go up on long mountain passes.
Both my 1HZ non turbos will begin to climb in temperature if I go over 50 mph uphill and I probably dont have any climbs as long or as steep as you probably have.
Click to expand...

The guy is multiposting. Same question on the 70-series.
Appears he has no fan shroud. Answered his question there.
See: https://forum.ih8mud.com/showthread.php?t=142669
 
sorry to disagree with the experts / other posters here.... but overheating at LOW vehicle speed means your fan/shroud needs attention. At high vehicle speed, the fan/shroud contributes nothing to cooling - no fan moves as many CFM as a truck travelling at 60mph. I suggest your problem is more likely to be the obstructions in front of the rad, preventing passage of air through the rad, or diverting cooling air away from the rad - or your fuel/air issue (especially if it's only happening at WOT) If all else fails, you can much improve air flow onto the rad by making an air scoop or dam - worked for me...
 
Ron R said:
It does need the fan shroud !!!
At this load the temp regulated fan kicks in and is ineffective if the shroud is not present.

Because the shroud is missing the fan is drawing the bulk of the air 'from the sides' so to speak, just pumping around the hot enginebay-air.
If the shroud is there the air, displaced by the fan, is forced to flow through the rad, coming from the front of the vehicle.
Click to expand...


yep, that is the answer, no doubt.
j
 
Sorry for multiple forum post, was aware this was uncool. Regarding the fan, the factory fan is a pusher? as it pushes air to the front of the vehicle? I know the fan clutch it temperature activated but i though it would engage regardless of a shroud. I will try a shroud. It just baffles me that every other type of driving outside of mountain passes it runs at a max of 175 degree F. How much do you think the size of the fan matters, as I have room to change this.
Thanks for the help guys
 
SURVEYOR CRUISER said:
Sorry for multiple forum post, was aware this was uncool. Regarding the fan, the factory fan is a pusher? as it pushes air to the front of the vehicle? I know the fan clutch it temperature activated but i though it would engage regardless of a shroud. I will try a shroud. It just baffles me that every other type of driving outside of mountain passes it runs at a max of 175 degree F. How much do you think the size of the fan matters, as I have room to change this.
Thanks for the help guys
Click to expand...


You find it odd that your vehicle runnning on the flat is 175 but when your pulling up a mountain pass the temp increases. Maybe on the flat your therm aint opening from too much cooling.

an 80C deg thermostat will open at 176F
 
SURVEYOR CRUISER said:
Sorry for multiple forum post, was aware this was uncool. Regarding the fan, the factory fan is a pusher? as it pushes air to the front of the vehicle? I know the fan clutch it temperature activated but i though it would engage regardless of a shroud. I will try a shroud. It just baffles me that every other type of driving outside of mountain passes it runs at a max of 175 degree F. How much do you think the size of the fan matters, as I have room to change this.
Thanks for the help guys
Click to expand...

The fan is not a pusher ,well it shouldnt be. It should be pulling air in the same direction as the natural airflow from moving forward.

There is a theory that says fan size should cover %70 of the radiator surface for effective cooling.

What does the FSM say your operating temp should be? IMO its not far off. The whole idea of pressurising it is to keep the coolant from boiling and boiling point is 212F.
There is a 88C (190F)thermostat available for the 3B and it becomes fully open at 212F;)

I think if you put the shroud on,correct the airflow it will be perfect.
 
After turboed my 2H ( water pump, shroud rad daba daba daba ) over 140 km/h at 3000 rpm and 14 PSI ( flat surface ) my 2H come hot ..

Why .. ? and I re check all cooling system parts ..

I make a list ..

1. Shroud
2. I belive in factory fan ( puller it pull throught rad air from front )
3. Fan Clutch
4. I have S blade flex a lite puscher in front of my AC condenser with 2000 cfm
5. water pump
6. apropiate amount of diesel ( controles with your EGT )

Conclusion .. there are a limit in your factory cooling system .. that are not designed to clear more than X% of heat result of your new power and performance.

Most if you have front rad obstructions ..

Just my .000002 cents ..
 
My thoughts of today after talking with the Northern Radiator the company who makes my aluminum rad is to go with an electric fan and shroud, which they claim will far exceed my factory fan's CFM. I should still have room for the factory fan in addition to this just as a safety precaution should the electric fan ever fail out in the sticks. The only thing I am trying to decide on now is how many CFM is too much. The guy from the rad company though 1900 would be plenty, though they do offer a fan which is 3000 CFM, but he though the 3000 CFM would result in no heat out my heater core. Has any tried an electric fan and can offer CFM suggestions.
Thanks:beer:
 
do not leave the stock fan in there if you electric. It will cause bad air flow and cavitate IMOP

search the 60 section, and mini trucks. They use electric fans, many pulled from junkyards. Taurus fans are common. Use that word for the search.
 
2000 cfm are plenty of .. and in my books enought .. remember not all is about cfm .. also keep in mind the amp rate of this fan ..
 
You must log in or register to reply here.

Share this page

Back
Top Bottom