Over heating while towing

Had similar problem , turned out to be the thermo coupler on the radiator cooling fan..had it replaced and all went well..
Check on archives if you want to do it yourself.. it may be quite simply some lubricant ..but as i had it done, don,t know how difficult or easy it may be !!

As above ....

Also, check to see if the radiator fins have become blocked w/- insects & such-like....

:)

Try the remedies mentioned above but also replace the radiator hoses.

The bottom one, if old and soft, sucks itself thin in those circumstances. It doesn't have any internal coiled wire to strengthen it.

Troy,
you will have to go through a series of checks starting with the easy ones.

If you are just pushing your foot to the floor then you maybe over fuelling the vehicle allowing the internal temps to rise, to start with, try backing off and changing down a gear so your engine is reving a bit harder to move the water around and your fan is pulling more air through the radiator, you will also not then be over fuelling it.

Check your air filter is clean.

Have you added any accessories in front of the radiator.

Check to see that your hoses are in good condition and not soft.

Pull the thermostat and test it in some boiling water to see if it opens fully.

You should be able to hear the viscous fan locking up when the temp starts to rise. If you can't you maybe able to buy some replacement viscous fan fan fluid from Toyota and top it up. If the hub is u/s I believe it is best to replace it with a genuine unit as I have had failures with after market ones.

Your water pump may also be worn.The radiator may need a clean or the cooling fins are eaten away.

If it is not using coolant then I wouldn't think you have a problem with the internals of the engine.
Is it blowing black smoke, this will indicate an over fuelling problem that could be coming from your pump.

Hope your problem is a simple one.

G'day Troy,
The cheapest and easiest items to eliminate first.
I carry a piece of 1/2" x 18" long copper tube bent at right angles at one end for 1" and pinched. Attach a small piece of rubber hose on the end to protect the fins and backflush your radiator fins in position using a garden hose. If you have picked up locusts or mud on your trip this is ideal.
Next change radiator cap if not already renewed.
Check all hoses are tight, I even doubled up some hose clamps, this definitely helped mine. Don't forget heater hoses. I thought if i didn't use water this would not be a problem, but it improved the cooling.
Viscous coupling but that costs $500+, or use the silicon top up as previously mentioned.
My 80 only gets hot when seriously loaded and towing, I fitted an electric p/p in series, but that only helped it recover quicker, didn't stop the overheating. As you know when your AC stops working it is getting hot.
Thermostat of course is worth checking.

Cheers,
Bill

Not mentioned yet but radiator fins get clogged on the inside- you can have your radiator 'rodded' down at the radiator shop for under $200, which clears the gunk out and keeps your temp where it should be.

Also check between the air conditioner condensor & your radiator- can get full of leaves, dirt, etc which prevents air flow.

When your temp does up do you hear your fan start to roar? You should hear it once your gauge rises from half to 2/3 if your fan is working as it should be.

assuming it is the 1HZ, same as mine .......
I have had HEAPS of trouble and we are not alone, one thing to keep in mind is the age of it, they are starting to get old and when new with all the standard gear we used to thrash them on the hottest of days and all went fine ....
With mine:
** All done because we where living in the desert at the time and have 3 young kids, car simply HAS to have A/C and still work on the hottest of days**
I tried the silicone, my opinion is just go get some quotes for a GENUINE fan hub and buy it, not worth the time mucking around with the old one and YES i tried it, the first lot leaked out so what is to stop the new stuff from leaking out again, just buy a new one....
Replace the radiator with a NEW unit, make certain it is exactly the same as the original or with more cores, beware of the cheaper thinner brass units ... when the radiator is out clean the fins on the condensor and "rake" them back into shape, you can get a "little" rake to straiten the fins up ..... it is also at this stage you replace the water pump and belts n hoses and i would also replace the timing belt and idler pully noting to get someone who knows what they are doing to do it, lately some have been quoting cheap to do a timing belt, they bend the support braket and belt comes off about 10,000klms later and trashes the whole motor
Make certain the fan blades are all ok and still there .....
Replace the thermostat with a new one, even if the old one tests ok .....
Replace ALL hoses ..... and belts
Replace the water pump
Yes it is expensive but you will end up doing all of the above any way and best to just do it and not regret it ...... what about $2000 - @3000 grand max, you will get out someware remote and will have travelled with hot & grumpy kids and missus and end up overheating and the kiss away $10,000 ......
We also invested in a "Engine Watchdog" worth ever cent ...
Like you i have kids, youngest now 3 so i could not have a hot car, winding down a window just dont cut it anymore ......
My outcome now is that on average to hot days will travel at any speed with full a/c and not get hot, on a VERY hot days (40+) it gets warm at 110klms, my next project is to replace the condensor and evap, both contribute to how cool it keeps ....... and they are what 15 years old now ????
Cheers
Good luck

Lots of suggestions above but if the 80 series motor is anything like the 2H I had in my troopie the reason for overheating was simply lack of grunt on the hills.

I had it right into the red zone just when getting to the top of Greenmount hill near Perth once, towing a big boat on a hot day.
Eventually replaced the motor with the BrunswickV8 and the problem went away. This was with the original radiator kept, it was not until several years after the conversion when the original radiator was eventually replaced due to old age.

If you don't want to spend a lot of money try this: turn off the air con before you get to a long hill.
Keep the revs up and the speed down as you climb it, working the motor in its power band.
Travel a little slower than 90 (85 perhaps), especially if there is a head wind and any time the temp goes above half way on the flat road.

Overfuelling has been mentioned above, the solution suggested was to use a smaller throttle opening, this will help but it is not the full or proper solution.

How long since the fuel system was serviced? Injectors, fuel pump pressure and timing all affect fuelling and consequently temperature. If it is more than 80,000km since the fuel system was looked at by someone who really does know what they are doing then I would invest in that.

I spent a lot of time and money chasing an overheating GU. One day at a good fuel system specialist made it pull harder, use less fuel and run cooler.

All the other suggestions are reasonable but the fuel system is the heart of a diesel. Yes it will be expensive ($1800 to $2000) but for me it was the genuine solution when all the other things were just treating symptoms.

Duncs

G'day Troy
One last thing as an outside chance. I recently chased an overheating problem in my 1HZ Troopie all through the usual suspects - fan, thermostat,radiator, hoses etc - and after 3 mechanics looked it finished up with.... a delaminated harmonic balancer. Slight and increasing slippage affects everything driven off the belts - power generation and cooling via both fan and water pump.

If it's just a cooling problem then maybe not but I'd look at it if there was any suggestion of poor charging, struggling aircon. Mine got to the stage of flopping about on the end of the crank before it became obvious.

Cheers
Mark

On one of our trips our old girl did the same. We tried a new radiator cap didn't work. But what got us home was turning the cap on then back a little bit. New radiator at home.

I would suggest if you are travelling around OZ, have the radiator replaced, new fan clutch, new hoses and belts, as well as a new thermostat. Nothing worse than breaking down on the side of the road with over heating problems.

You will definitely enjoy the trip a lot more.

Cheers Col.