Heating issues 2LTE :0(

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nightwind

nightwind

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Mar 4, 2018
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Today while waiting on the light the needle started to climb towards the RED line and nearly touched it drove it hard and switched the heater on but it only made a little difference.......

What SHOULD I do :o(

Very UPSET it is my daily driver
 
I am assuming that this is in a Prado? Has the cylinder head ever been replaced? Have a read through this thread:
LJ78 Big Fan Upgrade #2
You may want to start by flushing your radiator to make sure that it is in good shape and not clogged up. Also, swapping out the thermostat to a high flow one will make a difference.
 
nightwind said:
Today while waiting on the light the needle started to climb towards the RED line and nearly touched it drove it hard and switched the heater on but it only made a little difference.......

What SHOULD I do :eek:(

Very UPSET it is my daily driver
Click to expand...

If it's overheating while sitting at a traffic light, I'm afraid things are probably pretty bad. Generally it's pretty hard to get these to warm up at all when they are sitting at idle. But you'll have to tell us more if you want some serious help. What year and model is the vehicle for starters? How long have you had it? What is the history? Did this problem just start out of no where, or has it been progressively getting worse?
 
It is a 1990 LJ 70 Prado SX5 with the 2LTE engine, I don't know if the head has been replaced asked the previous owner but she has no clue it has got 200K on the clock, It has been the NICEST truck ever even in the cold Canadian -20 it is a half self start, from my little brain I think the engine is building a lot of Pressure. When I switch off the engine for 5 mins the needle will come down but then after 2 -4 mins of driving it will start climbing and when driving fast the needle will stay down but as the speed decreases and no wind hitting the RAD it will start heating uo again. I just added the Toyota Water mixed coolant, this problem started "all at once" with the AC running on a traffic light the needle climbed to H.

Apologies for not sharing this info before.
 
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Thanks for the info and pics.

One thing that can cause abrupt and major overheating is a cracked cylinder head. While the engine is really hot, carefully open the coolant reservoir lid. Leave the hose part in the coolant. Look carefully to see if there are bubbles coming out. If so, this can indicate combustion gases getting into the coolant. Chances are the reservoir will have been overflowing in this case, as the combustion gases push all the coolant out. Hopefully this is not your issue.

The next possibility is that your viscous fan hub has lost all its fluid and is not coupling any significant power to the fan. After your engine has been sitting all night, try spinning the fan by hand in the morning (before starting the engine obviously). If it spins with next to no resistance, it's likely the fluid is gone. Also, when your motor is hot and you rev it up at idle, you should hear the fan roaring as its pulling air through the radiator. If this is not happening, maybe get the hub serviced or replaced.

Another possibility is that your thermostat has failed or your radiator is clogged. Start your motor and feel the top main radiator hose as the engine warms up. There should come a point when the temp gauge reaches about 1/4 that the hose should suddenly start getting hot as coolant starts flowing. You can also have the radiator checked out by a rad shop to make sure it's not clogged internally or externally.

There are other things too...but start with that.
 
I just undid the lower hose pipe and flushed the whole system with lots of water
 
+1 for the viscous fan clutch. Hopefully it's not a cracked head. I just re timed my clutch as well as put 7k weight fluid and it solved my overheating problems. I am probably going to take the 7k out and try 10k just to make sure it's staying cool. My fan was never really engaged and it made a big difference. But.... I was only starting to warm up a little over medium while driving up big hills with the AC on full blast. The sudden, at idle, temp spikes is a little more concerning. GTSSportscoupe had suggested the High flow T stat as well to me prior and I will be ordering one from aus, flushing the system again and going with Evans waterless coolant just to make sure. These things like to chew heads.

Good luck, let us know what you find!
 
I hope it the fan clutch, where do I order the 10 K fluid . Thanks for the help
 
I just checked moving the fan before starting it seems pretty tight and wont rotate freely ...... but it is an old engine do you think should still go for the Silicone Oil Replacement ?

I will be taking her to a RAD shop to check
 
nightwind said:
I just checked moving the fan before starting it seems pretty tight and wont rotate freely ...... but it is an old engine do you think should still go for the Silicone Oil Replacement ?

I will be taking her to a RAD shop to check
Click to expand...

The fan hub might be fine then. I'd say next time the engine is good and hot, use your manual idle adjust knob to turn the rpms up to about 2000rpm. Open the hood and make sure the fan is roaring and moving a ton of air. Watch your fingers!
 
Hi! My fanclutch story:
On my 87 LJ73 (2LT) the fanclutch seemed fine, didn`t spin free when the engine was hot or cold, always the same resistant which I thought was odd... Did have some issues with the temp needle climbing when pushing it in hills etc. so I knew something was wrong. Decided to Open the fan-clutch and it was almost empty for fluid, the remains was thick, dark almost like honey. I think maybe the thick remaining fluid tricked me and made the resistant so it seemed ok. Anyway, cleaned it up, checked that the bi-metal still was functional with heat and a temp probe etc, filled it up with silicone oil and now its working like it should again!

So I would strongly recomend you to check the fan even if it might seem ok.
 
Ok, thanks guys, I just emptied all the coolant and filled it up with the RED waterless coolant from Toyota, but I will be taking the Fan out and inspecting it . There is a ticking sound coming from the fan, I left it running and the TEMP was going up and down the other thing I noticed is that when I press the Upper hose the needle goes down......

I REALLY APPRECIATE all your help, I will check and get back
 
If it's overheating at idle, and you don't have a bad head gasket or head, it could be as simple as a bad tstat. If you pull your tstat out and run it without it might give you an idea.
Pinching off the upper hose really shouldn't have an immediate effect on the temp reading. So, that's a mystery. Unless the tstat is sticking and it is momentarily forcing cool water from the upper hose back through to the temp sender. Which it right there before the tstat. But, that seems unlikely.
 
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