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How high is the return water temperature for a 1HDT?

Toadshade

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I had a faulty sending unit to my dash causing my temperature gauge to spike and making me throw my clutch and swerve off the highway in a panic. I replaced the sending unit and decided to add a Acutemp gauge to monitor the actual water temperature. I found a nice OEM dual port that connects to the block and measures the return water coming out of the block to the radiator. I knew the temperature would be higher but I thought I could still use it to measure any differences once I found out what the normal level would be. What I have found so far is that the temperature pegs out my meter past 130 degrees C! So I don't even know what the actual temp is. I was really surprised to see that it could very well be steam at that point and not fluid water. My sending unit has my dash gauge in the normal range now and my fluid levels are perfect. Just curious if anyone has any opinions or real numbers for the water temperature at the point where it returns into the radiator. If it is actually stem, I would have thought that there is no way the pressure could be contained with simple rubber and screw clamps.
 

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I have a sensor in the top hose on the right hand side of my radiator (looking from the front - so basically at the top of the hose shown in your picture). At this point I get a reading of 75-80c.
Now this may not be the actual temp but i just have it as a worry gauge i guess along with oil pressure and oil temp. You have me thinking now that I should rotate the sensor to be at the bottom of the hose to make sure I'm getting a fluid reading not a vapour one. I've driven many miles with that reading and the engine runs sweet as a nut.
 
I have a sensor in the top hose on the right hand side of my radiator (looking from the front - so basically at the top of the hose shown in your picture). At this point I get a reading of 75-80c.
Now this may not be the actual temp but i just have it as a worry gauge i guess along with oil pressure and oil temp. You have me thinking now that I should rotate the sensor to be at the bottom of the hose to make sure I'm getting a fluid reading not a vapour one. I've driven many miles with that reading and the engine runs sweet as a nut.
I have exactly the same, have done for many years. Mine reads about 80c too.
There shouldn't be any air in there so it has to be the coolant temp that it reads.
 
I can't honestly see there being steam present in a correctly functioning pressurised system. Not sure what pressure the 1HD-T runs at but a typical cooling system pressure is around 1-1.5 bar which is 120-130deg C.
If steam is present it means the coolant has boiled.
 
Sounds like I have an issue there (which can only be vapor) I have to do a little digging in to see what could be going on. But at the same time, If there is enough pressure then my gauge could be right at the point of boiling which is still not good. I looked up boiling points and pressure since I was curious now. 2 Bar would give me a temp of 120C so if I am pegged out at above 130 then it is boiling.
 
I have a sensor in the top hose on the right hand side of my radiator (looking from the front - so basically at the top of the hose shown in your picture). At this point I get a reading of 75-80c.
Now this may not be the actual temp but i just have it as a worry gauge i guess along with oil pressure and oil temp. You have me thinking now that I should rotate the sensor to be at the bottom of the hose to make sure I'm getting a fluid reading not a vapour one. I've driven many miles with that reading and the engine runs sweet as a nut.

I also have the same on my current 80 and had one on the previous 80. Both always read 70-80c under normal driving, spiking to an absolute max of 95-100c when engine severely worked (climbing alpine pass towing in 30c).
 
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I just bled the input on the manifold and checked the temperature of the manifold with an IR thermometer (while the engine was still pretty cool) and my thermometer read 35 when the gauge was 80. It is not definitive but it seems like something must be wrong with my gauge. It is the only other possibility. I called Accutemp and so far their assessment is a ground to engine block. I specifically ran a massive wire directly from my block to my gauges just for that reason so I am skeptical but I am going to isolate it to see if that does anything.
 
Thermostat dictates coolant temperature and they get sticky before failing altogether . while half your fluid is heated by the engine the other half is cooling in the radiator . It opens and swaps hot water for cooled water at say 80c but if it sticks .....................
 
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Thermostat should have "76 degree C" stamped on it. Valve should open to 10 mm in boiling water. If you have a mixture of glycol and water together with pressure rad cap you will have a boiling point way over 100 C but if you have 130C in your block it can only mean a faulty thermostat , radiator or water pump, unless you are losing coolant when engine is hot, ie it's coming out of the expansion vessel overflow pipe in which case you have a blown head gasket. Sounds like you have a faulty after market gauge. I would test it in boiling water and it should creep up to 100 C but no higher.
 
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