1985 Nissan Truck overheating while driving, but not

BEATNBRUISED

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1985 NISSAN TRUCK
4 CYL
2WD
MANUAL
140,000 MILES

I have a 1985 Nissan 720 pickup truck. Mileage 140000. My truck will sit and idle all day and the temp gauge will stay in the normal range, but as soon as I put it in gear and put a load on the engine the gauge starts to climb immediately. I have already replaced the thermostat, and water pump. I did a reverse flush on the radiator while I had it out. I poured water throught the upper and lower hoses while they were conected to the engine and there are no clogs there. No oil in the water, or vice versa. I'm out of ideas. There are no leaks, and its not losing any antifreeze. Could it be a clogged water jacket in the block?

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RASMATAZ

MECHANIC
75,992 POSTS

Retest the thermostat, check the fan clutch if it continues get it block and pressure tested.

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Thursday, February 26th, 2009 AT 3:02 PM

BEATNBRUISED

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Okay forgot to mention I replaced the fan clutch too, and this is my second thermostat. I've tested both of them in and out of the truck and they were working effectively

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Thursday, February 26th, 2009 AT 3:07 PM

RASMATAZ

MECHANIC
75,992 POSTS

Check for a retarded ignition timing and a clogged exhaust system. When push comes to shove get it block and pressure tested

Check your plugs see if you have coolant on it all of them.

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Thursday, February 26th, 2009 AT 4:25 PM

BEATNBRUISED

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Well I set the timing, it wasn't too far off, all the plugs looked good. But now my sensor light is on in the dash. Could a sensor be the problem? Honestly it doesn't feel like its not getting as hot as the gauge shows. I was wondering if the temp sensor could have gone bad and giving me an incorrect reading. Thanks for all the help by the way. I really appreciate it

Also, the exaust is good and clear

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Thursday, February 26th, 2009 AT 6:51 PM

RASMATAZ

MECHANIC
75,992 POSTS

Could be the engine temperature sending gauge/switch and the coolant temperature sensor be messing with you. Check it out and let me know

What sensor light is On?

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Thursday, February 26th, 2009 AT 10:18 PM

BEATNBRUISED

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It doesn't specify, its just a light that flashes and has the word sensor on it. I noticed today that the gauge goes up not only when I'm on the gas, but anytime the truck is moving. I was coasting down about a half mile hill with my foot on the clutch and the engine was at idle speed and the gauge was still on the rise, but as soon as I stopped the gauge went back down

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Thursday, February 26th, 2009 AT 11:21 PM

BEATNBRUISED

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5 POSTS

Well, I'm not really sure what I did, but I pulled the instrument panel out because the lights weren't working on it, and while it was out I reset the timing. After I got the lights working on the dash and got it back together I took it for a test drive and the gauge never went past the half way mark. I don't know what it was that fixed it, but I'm not gonna question it :)

Thank You for all your help, and when I have money I will definately make a donation

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Friday, February 27th, 2009 AT 5:23 PM

RASMATAZ