Hz1 temperature overheating

#1
Hi,
I have notice a possible overheating issue with my HZ1 engine not powered. I have a digital temperature gauge installed to keep an eye on my temperature.
While I was in the Simpson desert and driving on 2-3rd low gear at 25c temperature average, my engine was sitting nicely on 77-85c.
Once on highway, I've noticed the temperature to go regularly around 92-96c driving at 100km/h and soaring to 103-105c up on the hill. it will gradually go down again and sitting on 92c.

I was out on the bush with my family last week and temperature outside were up to 37c. While driving up to a steep hill without any 4wd engaged, the temperature soared to a whipping 115c to then gradually go down. I've checked the radiator once cold and it seems to have had a small overflow.
I would also say that the factory gauge hasn't moved at all.
Any suggestion for the problem? shall I get worried for some issue at the engine?
viscous fan seems to be ok, also my aftermarket gauge is bolted at the bottom of the head, very close to the exhaust pipe
Thank you all
 

itlldoo

Well-Known Member
#2
might have a load of crap ( grass seed and grass hoppers) between the Air con condenser and the radiator, limiting the air flow, clean it out, and get yourself a new radiator cap while your at it and see if that has an effect. small things first !:cool:
 
#3
What mods have to done to it?

How long does the viscous fan take to stop spinning once you turn the motor off, when its hot?

The factory gauges won't move until it gets real hot. Maybe move your transducer to somewhere away from the exhaust too.

Aaron
 

mauriceb

Well-Known Member
#4
Assume you mean the Toyota 1HZ . Most people fit the coolant sensor on the top radiator to engine housing at the front of the motor . There is a boss you can drill and tap to 1/8 npt. At 115 degree factory temp gauge should be well in the red and aircon won't work if it's on a 105. So is your aftermarket gauge correct.
temp sensor 1.JPG
temp sensor 2.JPG
 

mauriceb

Well-Known Member
#6
I have never used that position . Pretty sure that the engine flush drain plug if you removed a brass bolt from there. What brand gauge are you using?
A\C cuts out at 108, an indication if its still running when you reach 115 your aftermarket gauge is incorrect
This is a factory protection thingy . You can also buy a 42mm saas radiator hose adaptor cut the top hose and fit sensor there which would be easier.
 

mauriceb

Well-Known Member
#10
Wrong item to measure coolant. With the lug on the end that i see you will be measuring your metal temp and been right next to the exhaust it would be high . That has the same application as TM watchdog and Engine Guard. I use an engine guard as well as coolant gauge and metal temps a higher especially under load. My Lug sensor is fitted above cylinder 3 on the head. https://engineguard.com.au/
 
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#11
Some good information above. I was more asking about mods to determine wind resistance and weight. I would relocate or replace your aftermarket unit. If you haven't lost the aircon, then it isn't getting super hot.

Does it smoke at all? How many kms and has it had any work done to the pump/injectors?

Aaron
 
#12
Some good information above. I was more asking about mods to determine wind resistance and weight. I would relocate or replace your aftermarket unit. If you haven't lost the aircon, then it isn't getting super hot.

Does it smoke at all? How many kms and has it had any work done to the pump/injectors?

Aaron
engine re built has 50K and it had a few long trips across Australia in the last 4 years but looked well after. I always had a doubt about the sensor's position. I had it at the same spot of @mauriceb and I've never noticed such a high temperature. I will change it again next week and see how works out. no smoke at all
 
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