Cooling the 1KZ-TE motor:

[Shayne]

I have no doubt the oil was breaking down Beau , it was smoking when i removed the cap which gives some indication of how hot she was running . Perhaps the split pcv pipe allowed it to throw out more oil than it would normally ?

A catch can has been on the cards forever and if i order one it will likely sit in the box upstairs with the fancy temp gauge i bought about 2 years ago

As i type its just occurred to me that i needed a little oil (not much) on the same journey the year before when the pcv pipe was good i had an 80 following me then so i was likely traveling a fair bit slower .

I don't lose oil between changes otherwise and i'm not looking for any answers i just thought i would share the experience as this thread and the 1kz head problem remains an open question .

Might use fully synthetic oil on the next trip as it is supposed to have a wider range of operating temps though i haven't investigated that claim at all .

 

[Beau]

Regardless of the PCV system, the cause of the problem initially seems like the oil got too hot.

I would assume the oil temp is maybe slightly higher than coolant temp, but not by much. If you get round to installing the temp gauge maybe you'll have an idea of what temps you were running at those speeds. I'm pretty certain it'll be on the higher end of the spectrum but still safe. The oil cools via the same engine coolant as well, which was why I've previously inquired about an external oil cooler to possibly keep the oil cooler, and not put so much heat back into the coolant system.

Get the catch can, they're easy to install once you make up a bracket to mount them!

 

[Shayne]

Pistons drop onto a vacuum when pcv pipes not split so maybe that would explain why i lost so much oil and the low volume might explain the heat .

 

[Jack VZJ90]

I used to have the same problem many years ago with a HJ60 Diesel, and also heard from 90 series.
What comes first is the question ....
Does it overheat and then blows a gasket or a hose, ore does it blow a gasket and pressures cooling system ?
What happened to my HJ60 :
In the front behind the radiator was a big thermostatic cooling fan, engine driven.
The thermostatic fan holds a bi-metal attached to a small steel axle, that opens a valve to create friction.
When it's reaching a certain temperature, the valve opens (or closes) and the fan start moving at same speed as engine for cooling radiator.
The small steel axle, to regulate this valve, comes out an aluminium housing.
If the engine is used with respect and no towing or hard work, the valve axle stays in position.
In wintertime (salt on roads) rain / moisture the small axle and aluminium housing corrode.
So valve gets stuck !!!!!
When i pulled a caravan it started to run hot. (slower speed, less drive cooling)
If you heard air bubbles in your heater core under dash before final it's your gasket that blew.
If a gasket blows most likely radiator cap can't handle this pressure and hose clamp on top radiator blows of. (had this with my VZJ 90 two year ago)
If your head is straight, have an original seal and torque it right it must be good for years.

 

[Beau]

radiator hoses shouldn't blow. The rad cap is designed to bleed pressure to the expansion tank at around 0.9 bar, and will draw back coolant as it cools back down. This is why if a gasket blows it'll just pump out all the water via this cap, or if it's really bad it can end up burning the coolant as well leading to white smoke at the tail end.

 

[Jack VZJ90]

radiator hoses shouldn't blow. The rad cap is designed to bleed pressure to the expansion tank at around 0.9 bar, and will draw back coolant as it cools back down. This is why if a gasket blows it'll just pump out all the water via this cap, or if it's really bad it can end up burning the coolant as well leading to white smoke at the tail end.

Beau, you're absolutely right about the radiator cap.
Mine was polluted and completely blocked.
The clamp of the top hose came of including the top hose.
Suddenly al the dash lights came on and the engine stopped.
I suspect i had al small top gasket leak, because every time i started the car i heard small air bubbles in the heater core, which where gone in a few minutes.
A few weeks later the hose came off.

 

[tommi786]

Hi all. I run the 1KZ TE in my KZJ 78, Auto Trans. My rad developed a pinhole leak which i plugged temporarily with Araldite. It ran fine after that for more than 6 months (normal temp throuought on both the dash gauge and my aftermarket water temp gauge which would only marginally rise when the engine was under load going uphill) until I decided it was time to resolve the issue with a more permanent fix and ordered a brand new radiator from G&M radiators in Aberdeen. It arrived a few days later looking really good and shiny and the install was very easy. Filled it with 50% genuine Toyota coolant and water for the rest same as before. Also replaced the ATF lost during the cooler pipes disconnect and reconnect (around 250 ml). Made sure it was bled well with heaters on etc. ran really well for a week until we went out of town yesterday.

Under load when traveling uphill the temperature rise was more than before and for the first time the dash gauge moved from its normal midway position getting to around 2/3 way up. I eased up on the throttle and gradually the temp dropped back down but aftermarket gauge was still reading around 5-10 degrees warmer than normal (95 instead of the normal 85 ish).

As I eased up the AT temp light came on and I stopped and left the engine running to help cool off the ATF. The light went off in around 2-3 mins. I suppose the higher water temp caused the overheat. First time ever that light has come on. Worse is that I started leaking ATF between the gearbox and engine suggesting failure of the pump seal at the front of the Autobox. I suppose that the overheated ATF caused increased pressure and perhaps an already weak seal gave up under the added pressure? I had confirmed that the ATF cooler pipes through the new rad were not blocked or anything. Will be dropping the AT Box to check and fix the seal. If anyone's done this before, any guidance would be great.

My real question is whether a brand new QC passed rad could cause the problem. The cores from what I can see through the cap hole look clear. The fins were all straight and clear through. There is no shortage or excess coolant in either rad or expansion tank. The coolant is still clear red. Luckily engine looks fine. No unusual behaviors. Started first time from cold and oil looks very normal. No smoke or engine oil leaks.

As the rad was imported into Kenya where I live, I cannot send it back without spending a whole lot so am looking to recover my old one from the "to dispose shed" and have it rebuilt. Anyone with experience of a new non genuinerad causing such issues?

 

[Shayne]

First thing to check Tommi is the rad cap , heat causes pressure and the cap regulates it . A failed cap fits your symptoms well i think .

 

[tommi786]

First thing to check Tommi is the rad cap , heat causes pressure and the cap regulates it . A failed cap fits your symptoms well i think .

Hi Shayne. I am using the same old (which is actually only about a year old) cap (genuine Toyota 0.9 bar).

 

[Shayne]

That's likely your problem then i had a fancy TRD cap which replaced the original no problem at all but it didn't fit my new radiator .

 

[Beau]

If you live in a warm climate I'd advise to ditch the main rad for cooling your trans and just get a separate cooler all together. This has various pros. Firstly if your rad ever fails internally it won't mix with your trans fluid and damage the box. Secondly, when the engine is under load (or trans) they won't share heat with another and therefore should remain much cooler under loads.

Also make sure your viscous fan is working as it should (it's documented in this thread).

 

[tommi786]

Thanks for the advice. Any suggestions/web links to a good cooler? I suppose I should mount this right at the front before both the A/C rad and the normal coolant Rad. I will also be changing the rad cap on the new rad. Will go with a higher pressure 1.1 bar cap.

The fan sounds ok - it does roar when cold and also when hot and has a good amount of resistance to turning but not too much. Can anyone share the part number for the fluid that goes in it as I may as well top it up whilst I am at it.

 

[Shayne]

I would use the cap that came with the rad myself .

From memory 60ml of 10,000 cst silicon oil from a radio control model shop is what people usually use for the fan .

If your to empty all the coolant a new thermostat is relatively cheap for peace of mind , if you search the forum you should find a part number for a genuine stat that opens at a lower temp than than the factory fitted one .

 

[Beau]

https://www.summitracing.com/parts/...srese1-_-b-m&gclid=CKaRx6q8u9MCFZIdgQodmjMF5g anything like this would work - some are better than others. I actually used a much cheaper style one. Check out my thread here - https://www.landcruiserclub.net/community/threads/beaus-official-cruiser-story.145923/

Yup, place it in front of everything. I put mine in the centre so that the engine fan would assist in drawing air through.

Not sure if you should increase the opening pressure on the cap. Those hoses especially being old are designed to work within a pressure range. I'd stick with whatever pressure the stock rad had. There's no benefit in having a higher pressure cap.

 

[tommi786]

Thanks Beau. Like your thread.

Let me sort out the transmission leak first this week and once that is resolved will move on to a separate ATF cooler. Will also probably change the thermostat and the rad cap with genuine Toyota ones again. Although I was anyway running a 76 degree genuine thermostat that is not more than a year old.

Any of you with experience on the AT transmission seals replacement?

 

[Beau]

@BobMurphy is Probably the guy when it comes to these trans!

 

[tommi786]

@BobMurphy is Probably the guy when it comes to these trans!

Its in the Garage now - they will be changing the seal on the Transmission first. When that is done, I will be:

1. opening up the fan coupling and topping up oil - have ordered some 10000 cst oil for this. Will probably not go beyond 20ml to avoid full time lock-up
2. getting a separate trans oil cooler to mount up front. I will need to figure out the line that brings oil from the tranny and the return which I guess should be easy enough by removing one line and observing flow of oil when the engine is running, momentarily (is there another way?). I will want the coming in oil to go in to the top of the cooler.
3. my old rad is in a rebuild shop at the moment because if 1 & 2 don't resolve the issue for me, the new rad is definitely the culprit.

In the process will have flushed the whole fluid system and for good measure will renew the thermostat and rad cap - already had the 76 degree one and will retain that.

Lets see how it goes.....

 

[Beau]

Trace the lines from the box. The feed line goes more to the back of the box and is LOWER. The return line is higher and is slightly closer to the engine.

 

[tommi786]

Which one of these would you recommend:

Mishimoto MMTC-TF-2075 Universal Transmission Fluid Cooler, 510 mm x 190 mm x 19 mm https://www.amazon.co.uk/dp/B00SF9VHGY/ref=cm_sw_r_cp_api_qjcbzbR75S6A3

Or

Motamec Oil Cooler 25 Row - 235mm Matrix -12 AN JIC - Black Alloy https://www.amazon.co.uk/dp/B01IW2Q9WK/ref=cm_sw_r_cp_api_Fkcbzb3E0W4TG

I like the first as it's nice and large and an easier fit but the second has more rows in it and its design allows for a more radiator like drop in oil...... but looks bulkier and may restrict more airflow to the water rad.

Also I will fully bypass the factory radiator cooling for the ATF. Advisable or should I fit inline? Will it put too much pressure on the ATF oil pump?

 

[Beau]

I have one similar to the first one. People have used similar designs to the second one as well. So I'm not sure which one is necessarily better... The first one like you said will be a lot easier to mount. By size it looks a tad bigger as well. Any will do.

Won't put too much pressure on the ATF pump which ever route you go. Some have fit inline, others like me have just gone with a complete bypass. Since you're in a hot climate and don't have to worry about getting the trans up to temp so much I'd bypass the rad completely. Then just put piece hose on the bottom rad to keep debris from entering, and keep the original hoses/clamps in the truck. So if your external cooler fails at any point, you can revert back to the main rad.