1FZ-FE overheating

[JG1986]

Hi All!
Just wondering if sombody can try and help me solve this problem i have with my 4.5l 1FZ-FE 80 Series overheating?
Within about 20 minutes of driving around the suburbs the engine starts to go past normal running temp, and as soon as i accelerate a bit harder to go up a hil or something the gauge shoots up into the red and the coolant is boiling away.
I have replaced the radiator, fan clutch, Thermostat, and water pump with genuine Toyota items, but it hasn't helped.
12mths ago the top half of the engine was rebuilt, new head etc, so im wondering if there is a way that my mechanic stuffed something up when he did all that work to it.
I've spoken to Toyota and numerous cooling specialists, but left them scratching their heads.
If anyone has any thoughts or ideas as to what could be happening, please let me know.
Any help would be great Cheers!

 

[MoJ]

Do you have any other issues besides the gage indicating high temps? How's your exhaust look? How's the oil look? Any loss of coolant? Is the coolant full of contamination? Was it properly flushed? When the t-stat was replaced was it done with the jiggle valve at the 12 o'clock position?

 

[Corbet]

could be a defective thermostat or as mentioned installed incorrectly? Is your radiator cap working properly? (under pressure water boils at higher temp)

 

[JG1986]

Thanks guys
The coolant, oil, and exhaust are all fine, and the system was flushed out properly when i put the new radiator and thermostat in. I tested the thermostat before i put it in, and it is in the right way. The radiator cap is fine too.

This is why im scratching my head so much.

 

[Firedog]

How is the truck running? Could something be causing it to run lean(fuel filter, pressure regulator...)? Are you sure the timing was set correctly when the top end was rebuilt (if the timing is retarded it can cause or contribute to overheating)? Could the veins in the water pump be corroded? When it heats up is the radiator hot all over (possible plugged core)? Can you hear that the new fan clutch is working like it's supposed to?
Maybe the cam is off a tooth causing the timing to be off?

 

[cruiserdan]

Possible failed head gasket. Are there bubbles in the overflow?

 

[JG1986]

The trucks running fine. The water pump is brand new, so nothing is coroded and so is the fan clutch. And i forogt to mention before that i have checked the timing and its ok.
It could be the headgasket, as i am losing a tiny bit of coolant, but that mite be just evaporation from when it is boiling.
Just say it is the head gasket, why would that make the car overheat so quickly? The head gasket went last year and it never overheated once.
I,m goin to take the truck back to the mechanic who did the head gasket job last year so he can have a good look at it on monday.
keep giving me ideas though, cause there's probly somthing im overlooking

 

[Rondawg]

Have you checked the radiator hoses? Especially the lower hose, once it's at operating temp or when the over heating starts, pop the hood and check the lower hose by reving up the motor and see if the hose collapes. If it does collapse, get a new one, if not, good luck...

 

[LX_TREME]

Yup as CDan said. There are many possibilities, could be exhaust gases leaking into radiator, this is usually caused by a leaky head gasket. Or Boiling, too much water in the coolant, insufficient pressure due to a leak or a bad cap, partially restricted water jackets.

 

[zmw2101]

I have a similar problem in that my 1FZ-FE 1997 4.5L V6 with 234,000 miles was heating a lot. It cracked the water tank of the radiator too and I had to purchase a full steel tank for the radiator (Had it made to order). I always noticed that when the engine was running when parked, I couldn't touch the bonnet or radiator tank because they were so hot. Someone suggested I have the thermostat valve changed. I did, but the problem persisted. There was some loss of coolant, but overall the vehicle was drivable. Someone suggested that I remove the thermostat valve. I didn't know what else to do, I followed through. Lo & behold, now the temperature gauge has hit the bottom (literally fell to C) but even on short distances (like 3-4 miles), the engine loses half the coolant. Now, the same friend who earlier suggested to remove the thermostat valve suggests putting it back, but he prescribes that I have the head gasket checked by a mechanic. The mechanic insists that he would first check leaks in the water body and then would think about other things (such as changing head gasket). I am in a country where finding genuine OEM parts of 80 series is a nightmare. Does changing head gasket require any genuine parts from Toyota? If so, which parts and what might be their part numbers. Any help would be greatly appreciated.

 

[fatrap]

I had a similar problem in my Chevy Pickup. It was the radiator cap. I had replaced it as a matter of maintenance, but the one I bought was defective. It's hard to tell with a cap. I replaced it and the problem was solved.

 

[leonard_nemoy]

Here are some good links and hopefully a good place for you to start your research.

Head Gasket Thread for the FAQ

forum.ih8mud.com

How To Tell If Your Head Gasket Is Blown

forum.ih8mud.com

Goodluck

 

[zmw2101]

My radiator cap is fine.

I had a similar problem in my Chevy Pickup. It was the radiator cap. I had replaced it as a matter of maintenance, but the one I bought was defective. It's hard to tell with a cap. I replaced it and the problem was solved

 

[Marco Lau]

HG replacement is part of the PM for these trucks cause they are "SPECIAL"

 

[BILT4ME]

HG replacement is part of the PM for these trucks cause they are "SPEICAL"

It's all the extra HP just trying to get out!