Temp gauge malfunction

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Abletobecain
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Temp gauge malfunction

Post by Abletobecain » Sun Jul 14, 2019 8:13 am

Hello all,

So the temp gauge in my DD doesn't work. I'm also losing coolant which is obviously a bad combination. I think the coolant loss is from a small crack in the radiator near the drain plug. On that note, what is the part number for a double core replacement?

As to the temp gauge...I grounded out the temp sender wire and the gauge had no movement. Replaced the temp sender anyway. Replaced the thermostat with an Aisin as well. I just drove to the corner store and the gauge climbed till I shifted to 5th then dropped to zero. When leaving the store the gauge jumped to temp then dropped to zero again on a shift to third. Any idea what's wrong? Wire? Gauge? Also, what's the green plug next to the temp sender? I had to splice the wire on mine.
1977 BMW R100S 1WD ("Brunhilda"/Summer Fun)
2007 Tundra Limited Crewmax 4x4 ("Tetsuo Shima"/Hauler) SOLD :cry:
1983 DLX Tercel Wagon 4WD ("Charlie"/Daily Driver)
1987 SR5 Tercel Wagon 4WD ("Sprocket"/Off-road-Camping)
1985 SR5 Tercel Wagon 4WD ("Lucky"/Project)
1983 SR5 Tercel Wagon 4WD ("Cadaver"/Parts Car)
1987 DLX Tercel Wagon 4WD ("Lil Red"/for sale soon)

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marlinh
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My tercel:: 'Everett' Blue mint 4WD wagon and 'Rocky' 86 4WD Wagon
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Re: Temp gauge malfunction

Post by marlinh » Sun Jul 14, 2019 8:53 am

It looks like you have a parts car. Try plugging in another gauge. I have found the needles sticking in the past and tapping on the gauge it usually moves. I believe the green plug is a temp sensor for the primitive computers we have on these cars.

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Abletobecain
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My tercel:: 1983 4WD DLX, 1986 4WD SR5, 1985 4WD SR5, 1983 4WD SR5
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Re: Temp gauge malfunction

Post by Abletobecain » Sun Jul 14, 2019 8:55 am

I have the sr5 cluster in from the parts car already. The gauge didn't work on the stock one either. Tapping makes it jump and it held once a while back. I'm leaning towards it being the wire.
1977 BMW R100S 1WD ("Brunhilda"/Summer Fun)
2007 Tundra Limited Crewmax 4x4 ("Tetsuo Shima"/Hauler) SOLD :cry:
1983 DLX Tercel Wagon 4WD ("Charlie"/Daily Driver)
1987 SR5 Tercel Wagon 4WD ("Sprocket"/Off-road-Camping)
1985 SR5 Tercel Wagon 4WD ("Lucky"/Project)
1983 SR5 Tercel Wagon 4WD ("Cadaver"/Parts Car)
1987 DLX Tercel Wagon 4WD ("Lil Red"/for sale soon)

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Abletobecain
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Posts: 339
Joined: Sun Dec 09, 2018 9:18 am
My tercel:: 1983 4WD DLX, 1986 4WD SR5, 1985 4WD SR5, 1983 4WD SR5
Location: Kitsap County
Contact:

Re: Temp gauge malfunction

Post by Abletobecain » Mon Jul 15, 2019 12:04 pm

I've searched the forum and I cant' find a definitive part number for the double core radiator.

Does anyone have any experience with this one: https://www.rockauto.com/en/moreinfo.ph ... 0&jsn=1084

I just messaged the manufacturer and was told that it's a 1 row wide tube which is equivalent to 2 or 3 smaller tubes...does that make sense? Would it cool better being all aluminum?

It's slightly thinner (1.02" vs 1.25") than what I believe is a double the double core for the T4s: https://www.rockauto.com/en/moreinfo.ph ... &jsn=25082

Any help would be appreciated.
1977 BMW R100S 1WD ("Brunhilda"/Summer Fun)
2007 Tundra Limited Crewmax 4x4 ("Tetsuo Shima"/Hauler) SOLD :cry:
1983 DLX Tercel Wagon 4WD ("Charlie"/Daily Driver)
1987 SR5 Tercel Wagon 4WD ("Sprocket"/Off-road-Camping)
1985 SR5 Tercel Wagon 4WD ("Lucky"/Project)
1983 SR5 Tercel Wagon 4WD ("Cadaver"/Parts Car)
1987 DLX Tercel Wagon 4WD ("Lil Red"/for sale soon)

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splatterdog
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Re: Temp gauge malfunction

Post by splatterdog » Mon Jul 15, 2019 3:45 pm

Not that pattern failures are any guarantee of a solution, I've only had to replace the terminal and a few inches of wire whenever I've encountered temp gauge probs on these. The terminal is frequently corroded and things can go bad at the crimp. On a much newer Chev I encountered a 5 wire ground terminal that had anywhere from 1 good connection to open circuit even though the shared crimp looked OK.

A standard female push on terminal works fine.

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Abletobecain
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Joined: Sun Dec 09, 2018 9:18 am
My tercel:: 1983 4WD DLX, 1986 4WD SR5, 1985 4WD SR5, 1983 4WD SR5
Location: Kitsap County
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Re: Temp gauge malfunction

Post by Abletobecain » Mon Jul 15, 2019 4:09 pm

I replaced the connector too but none of the wire. I don't really want to open up all of the shroud on it but I guess I should at this point.

I was also thinking of just running a new wire from the temp sender to wherever it terminates...might be easier.
1977 BMW R100S 1WD ("Brunhilda"/Summer Fun)
2007 Tundra Limited Crewmax 4x4 ("Tetsuo Shima"/Hauler) SOLD :cry:
1983 DLX Tercel Wagon 4WD ("Charlie"/Daily Driver)
1987 SR5 Tercel Wagon 4WD ("Sprocket"/Off-road-Camping)
1985 SR5 Tercel Wagon 4WD ("Lucky"/Project)
1983 SR5 Tercel Wagon 4WD ("Cadaver"/Parts Car)
1987 DLX Tercel Wagon 4WD ("Lil Red"/for sale soon)

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: Temp gauge malfunction

Post by Petros » Mon Jul 15, 2019 6:48 pm

your temp gauge issue sounds like a bad connection somewhere. they do go bad, but I have found both the senders and the gauge very reliable and seldom is the cause. OTOH, corroded or loose contacts on a car this old is not unusual. test with an external jumper wire, if that is the cause, than running an new wire might be the easiest solution. Just make sure you route it so it will not cause any problems, or get damaged.

radiator cooling is based on total surface area of the fins, and the internal surface area of the tubes. I doubt one large tube is equal to two small ones (again, it is not the cross sectional area of the tube, but the area available for heat transfer, the surface area of the inside of the tube). There are aftermarket double row radiators available, all aluminum ones, that work well. I would no trust a single row rad, had bad luck with them, not enough cooling capacity for summer driving cross country.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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irowiki
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Re: Temp gauge malfunction

Post by irowiki » Tue Jul 16, 2019 12:04 am

I'll look at your links tomorrow but the radiator I bought for one of my older tercels was a thick single core radiator but it was twice the thickness of the stock single core.
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)

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