Why's a 1KZ-te overheating?

Joined: 09 Mar 2005

Friends 1kz-te keeps overheating, especially going up hill. Everthing has been checked and appears ok...raidoator, pumps etc etc.

I have one too, buts its ok.

We were wondering if a bigger/different fan would be the answer.

Joined: 02 Jan 2006 Location: Lara Victoria

The answer would be to find out why it's overheating...
If it's over heating under load then there is an inefficiency issue.
Could be a blocked radiator, either internally or externally. If it's internal then it will need to be dismantled and cleaned professionally.
Viscous hub on the fan may not be working correctly.
Can you hear the fan roar when he's pulling up hills?

Dan

Joined: 15 Apr 2004 Location: Out and about

I'll take a punt on it being a 3.0TD surf auto?

they are KNOWN to overheat- and it seems to come down to the torque convertor creating huge amounts of head in the oil for the trans, which gets transfered to the radiator and overheats the truck.

The manuals, and the aussie spec 1KZ-TE's werent affected.

Dads prado 3.0TD started to overheat going up hills after our simpson desert trip- pulled the radiator and except for a circle the size of the fan in the middle of it, the whole core was blocke with red mud!

couldnt see it was blocked without pulling the rad tho

Joined: 09 Mar 2005

ferrit wrote:

I'll take a punt on it being a 3.0TD surf auto?

they are KNOWN to overheat- and it seems to come down to the torque convertor creating huge amounts of head in the oil for the trans, which gets transfered to the radiator and overheats the truck.

The manuals, and the aussie spec 1KZ-TE's werent affected.

Dads prado 3.0TD started to overheat going up hills after our simpson desert trip- pulled the radiator and except for a circle the size of the fan in the middle of it, the whole core was blocke with red mud!

couldnt see it was blocked without pulling the rad tho

Yes, the overheating 1kz is an auto....and the other funny thing is my 1kz-te is a manual.

Both engines are from Japan imports installed to lj70's..bundy.

So the torque converter is overheating? How to settle the issue? Transmission oil cooler?

Radiator has been done and clutch fan is ok.

Joined: 09 Mar 2005

Ruffy wrote:

The answer would be to find out why it's overheating...
If it's over heating under load then there is an inefficiency issue.
Could be a blocked radiator, either internally or externally. If it's internal then it will need to be dismantled and cleaned professionally.
Viscous hub on the fan may not be working correctly.
Can you hear the fan roar when he's pulling up hills?

Dan

No, only the heat effect is noticable.

Joined: 11 Feb 2007 Location: Hobart

damnit ferrit, you beat me to it Razz

to help with the cooling, put a trans cooler BEFORE it runs into the rad. this will coo the tranny oil down, but then when it runs thru the rad as standard, it will keep it at opperating temp. the bigger the cooler the better, but DONT bypass the standard cooler in the rad, else you may find that you start to run it to cold if you have to good an aftermarket cooler...

Joined: 19 Jun 2006 Location: newzealand

its not so much the heat from thew trans cooler but rather the cooler itself blocking the flow of coolant.
one of the mods is to shorten/replace the transcooler so it dosn't block to flow so much. then add an external trans cooler to make up for the smaller cooler.

don't forget the normal things like blocked up rad or sticky EGR system.

Joined: 15 Apr 2004 Location: Out and about

macca81 wrote:

damnit ferrit, you beat me to it Razz

Theres a reason im bolting a MANUAL surf engine into my hilux Wink

Joined: 02 May 2003 Location: Visiting my house

ferrit wrote:

I'll take a punt on it being a 3.0TD surf auto?

they are KNOWN to overheat- and it seems to come down to the torque convertor creating huge amounts of head in the oil for the trans, which gets transfered to the radiator and overheats the truck.

The manuals, and the aussie spec 1KZ-TE's werent affected.

Dads prado 3.0TD started to overheat going up hills after our simpson desert trip- pulled the radiator and except for a circle the size of the fan in the middle of it, the whole core was blocke with red mud!

couldnt see it was blocked without pulling the rad tho

Used to have one, heard all the stories, tried many fixes. Problem and solution was $35.
START with silcon in the fan clutch - 2 tubes, 10,000 grade. Toyota ONLY sells it. It's a 30min job. Add to what's there, don't drain it.
If that doesn't fix it, then start down the harder paths.
DO NOT THROW AWAY THE THERMOSTAT whatever anyone says.
And those Autos (A343F from memory) are one of the best made, lockup torque converter etc. Same auto used to go behind the V8 Lexus. THey dont make heat on the highway unless stuffed.

Never overheated again, EVER. (Sand driving, towing 3ton trailers, mountain ranges, etc etc)

Paul

Joined: 11 Feb 2007 Location: Hobart

me3@neuralfibre.com wrote:

ferrit wrote:

I'll take a punt on it being a 3.0TD surf auto?

they are KNOWN to overheat- and it seems to come down to the torque convertor creating huge amounts of head in the oil for the trans, which gets transfered to the radiator and overheats the truck.

The manuals, and the aussie spec 1KZ-TE's werent affected.

Dads prado 3.0TD started to overheat going up hills after our simpson desert trip- pulled the radiator and except for a circle the size of the fan in the middle of it, the whole core was blocke with red mud!

couldnt see it was blocked without pulling the rad tho

Used to have one, heard all the stories, tried many fixes. Problem and solution was $35.
START with silcon in the fan clutch - 2 tubes, 10,000 grade. Toyota ONLY sells it. It's a 30min job. Add to what's there, don't drain it.
If that doesn't fix it, then start down the harder paths.
DO NOT THROW AWAY THE THERMOSTAT whatever anyone says.
And those Autos (A343F from memory) are one of the best made, lockup torque converter etc. Same auto used to go behind the V8 Lexus. THey dont make heat on the highway unless stuffed.

Never overheated again, EVER. (Sand driving, towing 3ton trailers, mountain ranges, etc etc)

Paul

agreed, never had a single issue on the highway. infact the only time i have had a problem was on ridiculously soft sand where i was redlining it to get up a dune(other choice was sit on the beach and wait for the tide, else redlining is a no-no) and when i put a hole in my rad(slightly exceptional circumstances)

Joined: 02 May 2003 Location: Visiting my house

me3@neuralfibre.com wrote:

ferrit wrote:

I'll take a punt on it being a 3.0TD surf auto?

they are KNOWN to overheat- and it seems to come down to the torque convertor creating huge amounts of head in the oil for the trans, which gets transfered to the radiator and overheats the truck.

The manuals, and the aussie spec 1KZ-TE's werent affected.

Dads prado 3.0TD started to overheat going up hills after our simpson desert trip- pulled the radiator and except for a circle the size of the fan in the middle of it, the whole core was blocke with red mud!

couldnt see it was blocked without pulling the rad tho

Used to have one, heard all the stories, tried many fixes. Problem and solution was $35.
START with silcon in the fan clutch - 2 tubes, 10,000 grade. Toyota ONLY sells it. It's a 30min job. Add to what's there, don't drain it.
If that doesn't fix it, then start down the harder paths.
DO NOT THROW AWAY THE THERMOSTAT whatever anyone says.
And those Autos (A343F from memory) are one of the best made, lockup torque converter etc. Same auto used to go behind the V8 Lexus. THey dont make heat on the highway unless stuffed.

Never overheated again, EVER. (Sand driving, towing 3ton trailers, mountain ranges, etc etc)

Paul

I should qualify - before the fluid add it would overheat whenever I did sustained over 3000RPM (might have been 3500 - was several years ago). Highway at 130km/hr - overheat. Hills at 75km/hr - overheat. Sand at 25km/hr - overheat.
Flat throttle at 2600RPM - no overheat.
Slow offroad in low range and 40+C outside and steep hills - no overheat.
The highway comment was re. the Auto trans.

The fan engaged, but would "slip" at higher revs.
I did also change to an 80 series fan, they are better.

Before that I was told teh fault was - radiator design, spot lights, radiator cap, coolant type, trans cooler in radiator, auto trans, head, head gasket, thermostat, coolant, water pump, boost, airflow, water flow, etc etc etc.

Paul

Joined: 19 Dec 2007 Location: Sydney

me3@neuralfibre.com wrote:

START with silcon in the fan clutch - 2 tubes, 10,000 grade. Toyota ONLY sells it. It's a 30min job. Add to what's there, don't drain it.
If that doesn't fix it, then start down the harder paths.

I hope this isn't a hijack...

I've a 3.4L v6 prado. I've done the 2 tubes of silicone oil, but it still overheats. I've also changed the thermostat, had the radiator out and looked over it, changed the radiator cap...

In my case it overheats when its working harder than usual - towing heavy things around, 4WD'ing, etc. It has also overheated a few times when I'm a few hours into a long trip on the highway, not towing anything. If it's working too hard maintaining the speed, shouldn't it overheat earlier or does it take a few hours for the heat to build up?

Anyways, any suggestions on what I check next? Could the fan clutch be unservicable, i.e. I just need a new one? How do I check if the radiator is blocked?