Overheating issues (1 Viewer)

[Postoy]

With your rad cap off can you idle the truck? Does it start to push coolant out? If it does I hate to say there is a very good chance the head is cracked. But there could be a small chance the head gasket blew.

There is a guy on Vancouver craigslist that has a 3L head for-sale around 800 bucks. (TOYOTA 2L-TE REPLACEMENT HEAD **3L Head**)

Maybe he would ship

I have a 1992 Prado Turbo Diesel. I just got a new water pump put in. It blew bubbles into my expansion tank. My Mechanic assured me it was just air in the system. I leant it to my Uncle. He overheated it twice and drove it about 8-10 km each way hot. It makes me wonder if there is air in the system because it over heats in a matter of 5 blocks. So! Are my heads toast? If 'yes', where do I get new ones in Western Canada? And do I use 3L heads instead of the 2LTE heads?

 

[Yoyota]

Thanks for the reply.
Will take a look.
When you say cracked head, thats the actual head right? Not the engine block?
Thanks again

With your rad cap off can you idle the truck? Does it start to push coolant out? If it does I hate to say there is a very good chance the head is cracked. But there could be a small chance the head gasket blew.

There is a guy on Vancouver craigslist that has a 3L head for-sale around 800 bucks. (TOYOTA 2L-TE REPLACEMENT HEAD **3L Head**)

Maybe he would ship

 

[Postoy]

Block should be good. Those heads are notorious for cracking in between the valves when over heated.

 

[Yoyota]

So, do you use the 2L-ET gaskets or the 3L gaskets?
I answered my own question.
3L fyi

 

[Lenny33]

So is this the proper fan clutch to replace with in the KZJ78?

80 Series 1FZ-FE Modified OEM Toyota Blue Fan Clutch

 

[Waikato Willy]

So is this the proper fan clutch to replace with in the KZJ78?

80 Series 1FZ-FE Modified OEM Toyota Blue Fan Clutch

from toyota NZ this is the part number for the hub "Viscous fan hub 16210-67010 RRP$472+GST"

ouch , honestly rebuild it with new oil, really easy, Im rough and I didn't wreck it, hobby shop for the oil-10,000 cst, a big decent phillips head screw driver to undo the hub and a clean bench

I didnt even drain my one I just filled it up level with the slots , you will see these when you open the hub, and i used a heat gun that had a temp adjust on it to adjust the thermal spring to open at about 84 degrees.You can see the metal slides open and close to let the fluid through
I adjusted mine all the way to the end of the slot to make it work so the spring is surely worn out
Normal driving around I dont hear the fan at all till I hit a hill
When I stop in traffic or at an intersection when I take off the fan engages for about 10-20 seconds no matter what the weather is like its really loud so you will definitely hear this engage

 

[Lenny33]

from toyota NZ this is the part number for the hub "Viscous fan hub 16210-67010 RRP$472+GST"

ouch , honestly rebuild it with new oil, really easy, Im rough and I didn't wreck it, hobby shop for the oil-10,000 cst, a big decent phillips head screw driver to undo the hub and a clean bench

I didnt even drain my one I just filled it up level with the slots , you will see these when you open the hub, and i used a heat gun that had a temp adjust on it to adjust the thermal spring to open at about 84 degrees.You can see the metal slides open and close to let the fluid through
I adjusted mine all the way to the end of the slot to make it work so the spring is surely worn out
Normal driving around I dont hear the fan at all till I hit a hill
When I stop in traffic or at an intersection when I take off the fan engages for about 10-20 seconds no matter what the weather is like its really loud so you will definitely hear this engage

Yeah, I guess I better rebuild then - thank you! I never hear my fan at all - that has to be my issue.

 

[Lomoski]

from toyota NZ this is the part number for the hub "Viscous fan hub 16210-67010 RRP$472+GST"

ouch , honestly rebuild it with new oil, really easy, Im rough and I didn't wreck it, hobby shop for the oil-10,000 cst, a big decent phillips head screw driver to undo the hub and a clean bench

I didnt even drain my one I just filled it up level with the slots , you will see these when you open the hub, and i used a heat gun that had a temp adjust on it to adjust the thermal spring to open at about 84 degrees.You can see the metal slides open and close to let the fluid through
I adjusted mine all the way to the end of the slot to make it work so the spring is surely worn out
Normal driving around I dont hear the fan at all till I hit a hill
When I stop in traffic or at an intersection when I take off the fan engages for about 10-20 seconds no matter what the weather is like its really loud so you will definitely hear this engage

Rebuild it. I did mine as well and it's working the same as yours now. I went with 10000 CST oil and the thing roars now. Definitely robs torque but a small price to pay vs a head.

 

[Lenny33]

Rebuild it. I did mine as well and it's working the same as yours now. I went with 10000 CST oil and the thing roars now. Definitely robs torque but a small price to pay vs a head.

So just to be sure, it is pretty definite hearing the fan right? If I’m not sure that I hear it, then it isnt working, right?

 

[Lomoski]

So just to be sure, it is pretty definite hearing the fan right? If I’m not sure that I hear it, then it isnt working, right?

When the fan is working it will roar. If you haven't rebuilt it then I can almost guarantee that you are not getting proper airflow and cooling with the fan. It is super easy to rebuild. Search for blue fan clutch mod in the forum here and you'll get a step by step of how to do it. Probably don't need to replace, just rebuild. I timed mine so it opens at the lowest amount of heat possible and it works quite well.

 

[JimmyPrado]

Put your hood up and have someone start the truck. It should roar pretty good and then slowdown when starting a cold engine.

 

[Lenny33]

If I can stop the fan with a magazine, is the clutch bad?

 

[GTSSportCoupe]

If I can stop the fan with a magazine, is the clutch bad?

I wouldn't recommend trying that....

The clutch's don't really go bad, they just need new fluid after a while. Usually the way they do fail is the spring corrodes/breaks or the oil seal starts leaking (by the shaft).

There is no question at this age the clutch needs new fluid; just do it. You can buy the silicone oil at a RC car hobby store.

This is the stuff I use. Anything between 5000 and 15000 will work. I recommend 10000. I opened my fan clutch after having this stuff in there for a few years and it was still in good shape, not burnt or anything.

 

[Lenny33]

I wouldn't recommend trying that....

The clutch's don't really go bad, they just need new fluid after a while. Usually the way they do fail is the spring corrodes/breaks or the oil seal starts leaking (by the shaft).

There is no question at this age the clutch needs new fluid; just do it. You can buy the silicone oil at a RC car hobby store.

This is the stuff I use. Anything between 5000 and 15000 will work. I recommend 10000. I opened my fan clutch after having this stuff in there for a few years and it was still in good shape, not burnt or anything.

I already did try it.
Fan stops with a magazine at operating temps. Once engine is then turned off, fan spins relatively easy by hand.

Guess I better stop investigating and get to changing fluid!

 

[GTSSportCoupe]

I already did try it.
Fan stops with a magazine at operating temps. Once engine is then turned off, fan spins relatively easy by hand.

Guess I better stop investigating and get to changing fluid!

Even with heavier fluid, the magazine could still stop it if it's working right. The spring in the front engages or disengages fluid from entering the internal clutch surface. It's temperature dependent. The fluid is constantly getting pumped into an internal reservoir. So if the fan has been turning for a while and it's cold out, it may actually spin easily, as no fluid should be in the clutch surfaces.

After a vehicle has been sitting for a while the fluid pools in the bottom of the fan clutch. So if you spin it by hand it will be stiff for part of the rotation, and be easy for part of it. It will also roar on start up until the fluid is pumped back into the internal reservoir.

When the clutch is hot and the spring valve has opened to allow fluid into the clutch surfaces, the fan should be stiff, and roar when the engine is revved.

They're pretty marvelous little bits of engineering really.

 

[Lenny33]

Even with heavier fluid, the magazine could still stop it if it's working right. The spring in the front engages or disengages fluid from entering the internal clutch surface. It's temperature dependent. The fluid is constantly getting pumped into an internal reservoir. So if the fan has been turning for a while and it's cold out, it may actually spin easily, as no fluid should be in the clutch surfaces.

After a vehicle has been sitting for a while the fluid pools in the bottom of the fan clutch. So if you spin it by hand it will be stiff for part of the rotation, and be easy for part of it. It will also roar on start up until the fluid is pumped back into the internal reservoir.

When the clutch is hot and the spring valve has opened to allow fluid into the clutch surfaces, the fan should be stiff, and roar when the engine is revved.

They're pretty marvelous little bits of engineering really.

Thank you everyone for your input!
This seems pretty clear cut to me:
1) truck is heating
2) no roar at start up or at high speed
3) once truck is at operating temp, then turned off, fan still spins easily
4) it’s a 25 year old rig.

 

[Lenny33]

When the fan is working it will roar. If you haven't rebuilt it then I can almost guarantee that you are not getting proper airflow and cooling with the fan. It is super easy to rebuild. Search for blue fan clutch mod in the forum here and you'll get a step by step of how to do it. Probably don't need to replace, just rebuild. I timed mine so it opens at the lowest amount of heat possible and it works quite well.

Lomo - I am going to do thermostat while I’m at it - which one did you end up going with?

 

[Lomoski]

Lomo - I am going to do thermostat while I’m at it - which one did you end up going with?

I went with an OEM Toyota one 82c. Was thinking about putting a tridon one in the spring when I drain the 60/40 and put in 30/70 for the summer.

 

[JDM Journeys]

I'm possibly in the hunt for a KZJ78 (or a PZJ, but it depends what comes up for reasonable $), so just wanted to shout out to the contributors of this thread. Lots of info and misinfo about the 1KZ out there. This is good solid stuff for owners to act on. Thanks!

So newbie question, just to add onto this thread: is there a high probability of a head replacement on the 1KZ like it seems to be on the 2L in these otherwise stout rigs, or are the later 1KZ's a little more forgiving overall? And just for clarification, once the cooling system has been gone through, is an EGR delete and trans cooler separation still recommended?

I've had two Mitsu 4D56's, a 4M40, and a 4M41, and have not (knock on wood) lost a head or head gasket on any of them, even though urban legend says I should've. So I fear I'm falling into the google-hysteria of thinking its a given on the 1KZ?

 

[GTSSportCoupe]

I'm possibly in the hunt for a KZJ78 (or a PZJ, but it depends what comes up for reasonable $), so just wanted to shout out to the contributors of this thread. Lots of info and misinfo about the 1KZ out there. This is good solid stuff for owners to act on. Thanks!

So newbie question, just to add onto this thread: is there a high probability of a head replacement on the 1KZ like it seems to be on the 2L in these otherwise stout rigs, or are the later 1KZ's a little more forgiving overall? And just for clarification, once the cooling system has been gone through, is an EGR delete and trans cooler separation still recommended?

I've had two Mitsu 4D56's, a 4M40, and a 4M41, and have not (knock on wood) lost a head or head gasket on any of them, even though urban legend says I should've. So I fear I'm falling into the google-hysteria of thinking its a given on the 1KZ?

The chances of a 1KZT head going is probably about the same as a 4M40. Definitely not as bad as a 2LT or a 4d56 for example. It all depends on how it was treated before you got it, how many hours on it, and even what vintage it is. Like the 2LT, I think the 1KZ's got better as time went on. I think it's wise to consider the possibility of having to do a head at some point however. Account for it in your budget. I'd say on average, the 1989-1994 2LT's needed cylinder heads within 100,000km, where the 1KZ's seem to last more like 200,000km+ before needing one.