RUnning Hot and CANT figure out why

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Thermostat is brand new with both seals
100% sure no visible leaks
Total coolant system flush today
Engine is newly rebuild
Radiator is new
System seems to be fulll

Temp gauge rides dead on the Middle dash in the gauge which Is hotter than any other cruiser i have have ever had. At times when i am riding down the road it will shoot all the way to the hottest redzone and then just it will fall straight back down to the middle dash again for no apparent reason. I am out of ideas as this rig was rebuilt pretty thoroughly just a few months ago by the rising sun guys so all is new and runs great. could it be a faulty wiring issue/connection? Temp sensor i would assume is new. Please help!!!
 
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Im pretty sure its not actually over heating. When your temp gauge goes up, does your fuel gauge go up with it? Its a common problem of the fuel gauge shorting out or something which causes the fuel and temp gauges to spike. It had me terrified for a while as well. Now I just drive with it. Next time it does it watch what your oil pressure gauge does, if it stays constant then its not over heating.
 

RockDoc

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x2 on the gauge spike

If it is a new sender, maybe it is a bit off in calibration? Have you burped the system? Good heat out of the heater?
 

2mbb

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x3 to watch to see if the fuel and gauge goes up too. I used to have a VW Rabbit that had this issue for most of it's 250K life. I never did figure out what the problem was. probably a short or a ground fault.

I recently replaced my 80degC theromostat with a 90degC thermostat. the 90degC is stock for the FJ60 & FJ62. SOR also sells an 80degC thermostat for the FJ60, but it's not listed in the Toyota parts microfiche as an option. With the 80degC my temperature used to run in the lower quarter. With the 90degC it runs about mid way. I just replaced mine and haven't burped the system yet but it's been holding steady at the midpoint.

so, make sure you burp the system and get all the air out. Confirm what temperature thermostat you had and have. Watch the fuel gauge when the temperature spikes. Let us know what you find out.
 
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2mbb: So you had an FJ80 therm in your 60? And you went back to the stock? Just trying to follow. Did it run cooler with the 80degC?
 

2mbb

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Oops. Maybe I'm wrong about it being an FZJ 80 thermostat.

SOR sells two thermostats for the Land Cruiser through the FJ80 (F, 2F, 3FE engines) one is 80degC and the other is 90degC. The first time I replaced my thermostat, I purchased the 80degC from SOR. However, the Toyota parts microfiche specifies only the 90degC thermostat. So I recently purchased one of those and installed it.

The truck did run cooler with the 80degC thermostat. However, it got to the point that it ran so cold I would have to use the choke very often. Pretty much any time I shut the engine off, regardless for how long, and sometimes if I was idling at a stop light it would get too cold. It could be the thermostat was stuck open though.

My real point was that now that I have a stock thermostat installed (90degC) my temperature runs about midway up the temperature gauge. I wanted 77Cruiser to know there are different temperature thermostats and to check to see if he didn't switch from one that was lower temperature to a higher temperature one.
 
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x2 on burbing the system might be an airpocket, and watching the guages for collateral spikes in other fields.

i have the 80degree in mine and it runs about a third up on the guage. i have no problems having to use extra choke and it runs well. gets hot here in the summer and not too cold in the winter so the 80 is a good fit for me.
 
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Thanks for the input. All indications tell me that the truck doesnt run hot and the gauge is just messing up. Heat works good and so does the A/C. I am not sure on the thermo, i will have to check what went in there to see. It came from the Toyota store here so i would guess they prob put a 90 if that is typically stock. Oil pressure stays very consistent and When i got in last night, the fuel gauge was at mid and then spiked up to almost a full tank so that could be right. Is there any way to fix that? Do the contacts on the gauges need cleaning or something along those lines? I will try the burp method but I think since it was just flushed out yesterday at the shop I should be ok.
 
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Thanks for the input. All indications tell me that the truck doesnt run hot and the gauge is just messing up. Heat works good and so does the A/C. I am not sure on the thermo, i will have to check what went in there to see. It came from the Toyota store here so i would guess they prob put a 90 if that is typically stock. Oil pressure stays very consistent and When i got in last night, the fuel gauge was at mid and then spiked up to almost a full tank so that could be right. Is there any way to fix that? Do the contacts on the gauges need cleaning or something along those lines? I will try the burp method but I think since it was just flushed out yesterday at the shop I should be ok.

your spikes may be related to bad grounds in the system show clean all your grounding points. good practice anyway
 

RockDoc

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When i got in last night, the fuel gauge was at mid and then spiked up to almost a full tank so that could be right. Is there any way to fix that? Do the contacts on the gauges need cleaning or something along those lines?

I believe there is a thread in the FAQ on this.
 

REKCUT

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IMHO first thing any 60 owner should do is install mechanical guages so you can actually see what your temp and oil pressure is. Very, very hard to discuss something with statements like" its sitting in the middle of the line" or " its between the the top to lines". Its much better to have a reading like 182 deg to measure your temp againts the norm. The mechanical guage also lets you see you temp after you turn off the truck.
 
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IMHO first thing any 60 owner should do is install mechanical guages so you can actually see what your temp and oil pressure is. Very, very hard to discuss something with statements like" its sitting in the middle of the line" or " its between the the top to lines". Its much better to have a reading like 182 deg to measure your temp againts the norm. The mechanical guage also lets you see you temp after you turn off the truck.

sage advice...its on my list of things to do!!!!
 
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When I bought my 60 and drove it from Alabama to GA 4hrs the temp gauge would spike and fall.......about gave me a heart attack!

I cleaned the grounding points (thread in FAQ) and it stopped.
Its worth a shot and doesn't take long at all.
 

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