In low range the tires are turning slow due to gearing but the motor rpm's should be faster. How much bigger did you go with tires? What do you have for a motor and what kind of fan? Electric fans are great for adding cooling but make sure your radiator is not got clogs and your thermostat is good. When you add load to your truck you might find things that did not show up before...ie bigger tires. Also check your water pump and make sure that is in good condition.

MUDD

/wwwthreads_images/icons/wink.gifIf it's stuck, force it! If it break's,it needed replacing anyway!!!

 

I went with 33x15.50-15 TSL sx's I have a 400, I wasnt really reving the low range just creeping on a rough dirt road. I looked at the radiator it looks pretty clean inside, if the thermostat was bad wouldnt always overheat? It never overheats on the raod. What kind of electric fan?

 

More than likely your fan just wasn't turning fast enough to keep the motor cool with the extra load of those big wide tires. As far as electric fans go, there are many good ones out there. Check out www.summitracing.com or Proformance Automotive Warehouse at www.pawinc.com for prices and sizes. Summit probable has the better online catalog of the two. Good luck.

MUDD

/wwwthreads_images/icons/wink.gifIf it's stuck, force it! If it break's,it needed replacing anyway!!!

 

Maybe you aren't getting enough airflow through the radiator from the fan at low speed.

Do you have a fan shroud? This alone can do wonders.
Do you have a clutch style fan? if so, does the clutch still work?
Do you have a Flex fan? if so is it spaced properly? Is it the proper size? does it fit inside the shroud at right spot to get the most airflow?

Its surprising how much air will get sucked through a rad when the fan is setup correctly.

Anyway, Elec fans are great too. I added one when I had a 78. Didn't use a temp sensor, just had it on a switch. Used it only at idle when I saw it was needed. Also gives you the choice to turn it off if you get into mud or deeeeep water.

- Dan

99 4Runner (wifes grocery getter)
88 Bronco ** SOLD **
01 TJ Arriving in August