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Running temperatures ?

Paulpen

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Sep 21, 2012
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Hi guys - added a checp water temperature gauge to mine last week and getting what I think is a high reading. Once warm its at just over 100C or with the heaters fully on for a few mins its about 95C.

I though it might be the gauge so swapped with both a spare of mine and a friends and all shoing the same temperatue.

Then though it could be the sender so swapped that with another one and still the same temperature.

Also run seperate lives and earths direct from the battery and still the same so im ruling out the gauge being dodgy and thinking im running slightly hot.

Dropped the coolant out of it tonight and it just seemed like water in there. Chucked a hose though the radiator and seems to flow freely, also put it down the upper engine hose and gently trickles slowly out the bottom (slowly due to the thermostat being in the way im assuming).

Bled it all with the heater on hot and the front end a few feet up in the air until there were no more bubbles and im still running at the same temps !

The only things I can think of that are left is the viscous fan as it does not really roar unless you have the revs quite high or maybe the water pump is not circulating it well enough ?

The gauge is measuring from the middle of the top radiator hose so am I reading in the right place ?

Also it only seems to be the top third of the radiator that actually seems to have any heat in it - the lower two thirds and the bottom radiator hose are rather cool :wtf:

Sorry for the mega long post !
 
What coolant you used? Toyota red is the ideal.
 
Honda blue

I know its not Toyota red but ive got loads of it from previous cars and its better than the water that was in there :(
 
I would say your Rad is on its last legs, and they are so easy to change its not worth messing about.

Also whats your normal Gauge saying? is it sitting any higher than it normally does?

Have you had the Thermostat out and checked its working as it should?
 
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Why would you say radiator though as its seems not to be blocked as a hose pipe in the top comes out the bottom just as fast ?

Steve - where did you gets yours from ?

Took the fan apart today and added some of the 10,000 cst oil and checked the operation on the metallic spring under heat - both seem ok.


Im still doubting the gauge that ive fitted tbh. Using an infared Ive pointed it at all kinda of areas and got the following readings :
Top hose is about 80ish
Top of radiator is 75ish
Bottom of radiator is 25ish

Even the head and block are about 80ish so can the coolant inside really be over 20 degrees higher ?

Im tempted to buy a different guage and sender from a totally different supplier to see what they say !
 
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Paulpen wrote
Also it only seems to be the top third of the radiator that actually seems to have any heat in it - the lower two thirds and the bottom radiator hose are rather cool :wtf:

from what you said earlier on it sounds like the bottom of your rad maybe getting a bit corroded and not circulating properly.
 
I see what you are saying silvercruiser but could it be that the radiator and fan are cooling as they should thue the cooler coolant sinking to the bottom of the radiator ?. Both ideas seem to make sense but how do you determine which one is correct ?

Steve - Think im going to buy one and temperirally (sp?) fit it to the same location for a head surface reading so at least I can compare it to someone !

Just been reading this topic that seems full of information http://www.landcruiserclub.net/forums/showthread.php/41965-Cooling-the-1KZ-TE-motor and from reading it all im thinking mine is operating fine ?

Ordered a surface mount sender like Froggy Steve has been using and going to compare the readings I think.

May also buy a better guage and sender but might be a waste of time and money !
 
I think it's rather normal for the bottom of these rads to be cooler than the top, sounds wierd but I've heard this from quite a few people now
 
IIRCHeated water enters radiator from top of engine and turbo (top hose), passes through rad for coolingcooled water enters near water pump so bottom of radiator should be considerably cooler than top.
 
So the generaly operation of my engine seems normal then - other than the high reading aftermarket gauge ?
 
Could it be the location you are taking your readings? I would think the top raditator hose would be fine to take reading's but I wouldn't expect them to be as high like you're experiencing other than if your viscous fan is not operating as it should?

The thermostat opens at 86 degrees (I think) so ideally you shoudn't have anything higher than that, if everythings working as it should
 
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I would have thought the highest (hottest) place would be the best place but am open to suggestion on anything :)

Although the thermostat opens at 86 its on the bottom hose and thats not seeing anything past 30 degrees as im assuming the fan and radiator and cooling as they should ?
 
Ah, the perennial problem . . .

As the thermostat is at the bottom of the block, and it only has a small bleed hole in it, the coolant won't be flowing through the radiator until the bottom of the block is hot enough to open the thermostat (which then shuts as its doused in cold coolant from the bottom of the radiator).


The top of the motor gets very hot, very quickly, when under load but the thermostat doesn't react quickly enough to reduce the temp. I have never understood why Toyota adopted this design on a heavy road vehicle.


The result is that we suffer cracked heads. I have fitted a 76 deg thermostat to try and save the motor when towing horses up hills; it seems to work.


One thing - Have you removed the radiator recently ??? I found that the external matrix on mine was blocked with dust, leaves, grass etc which had built-up between the aircon rad and the engine rad. Cleaning that out helped enormously!



DSCN4525.jpg




The build-up can't be seen without removing the radiator I'm afraid (unless you've got an endoscope or one of those optical tools for looking for pipes and cables in cavity walls!).

There have been a few posts about fitting aftermarket temp gauges to the 90 series. The temp gradient between the top and bottom of the motor is quite concerning.

Bob.
 
Not had it out but managed to look down the gap and get some compressed ait down there to blow the dirt out :)

Todays efforts showed a revelation !

Managed to borrow a multimeter with a temperature probe attachment which I managed to get between the top hose and the radiator enought to get it wet (although a very slight seepage).

Ran the engine up from cold and it settled at mid to high 70's on the multimeter - it was already showing 100 on the gauge !.

Then ran the engine at quite high rpm for a few mins whilst still watching the multimeter and having a friend in the car watching the gauge. Multimeter got up to 89 at the highest point (at which point the fan started roaring and the bottom hose became warm to touch). What did the in car gauge say - still 100 !.

So pretty much decided that a cheap gauge is worse than a good one as id rather have no reading rather than false ones !

Ive ordered a surface mount one like a few people on here have that ill mount for a week or so to keep an eye one things but have also ordered a VDO gauge and sender so will get that fitted too and will then know exactly whats bad although im quite confident that its the cheap temperature senders that have been supplied to me !
 
I like the idea of one butI still prefer the idea of measuring the water temperature rather than the metal temperature tbh
 
Seems ok you see a big variation in temps both on the engine and the auto box
 
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