temp gauge woes
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Tuned
Joined: Mar 2007
Posts: 317
Likes: 0
From: Sabin, Mn
temp gauge woes
hey guys. I need some pointers on what to do with this darn temp gauge. when i got the truck, the gauge always read that the motor ran cool. like 115 cool. lil warmer on the highway(between 115 an next number). i started digging into it. I replaced the temp sender in the head, replaced the thermostat with a 195 napa unit and new coolant. the darn thing still reads cool. now, if i shut it off and let it sit for like 20 minutes or so, then turn the key on(engine not running), the gague will shoot up to bout 160 and then drop down to that same spot,right around 115. I replaced the terminal end and have checked the wiring the best i can(visual only) and cant find anything. I have even put the temp sender wire on a ground and the gauge shoots right up and pegs out at the hot and stays there but is slowly creeps back down(toward cold). is there somthing else i should be checking?????? could i just have a bad wire????? is that lil voltage regulator bad?????
Last edited by 64fordf100292; Sep 29, 2007 at 11:29 PM.
Cargo Master
Joined: Sep 2005
Posts: 2,954
Likes: 64
the first thing you have to do is find out exactly what themp the engine is at. Have you put a thermometer in it with the engine running to see what the actual temp is?
If it is infact running at 115F then you'll need to restrict the radiator surface.
If it is infact running at 115F then you'll need to restrict the radiator surface.
Lead Driver
Joined: Aug 2003
Posts: 6,305
Likes: 18
From: Boulder Creek, Ca
If experiencing problems w/ other gauges, fuel, oil pressure, then possibly the Constant voltage regulator, small metal box usually secured to back of instrument panel. Suggest check all the connections to the regulator and gauges. Also make sure good ground between instrument panel and dash. Addes an extra ground wire on my 65. Couple of test, disconnect lead to the the sending unit and put a 12 volt lamp between the gauge lead and ground then turn ign. on, if lamp flashes then the volt. regulator is functioning and the gauge circuit is not broken. If lamp stays on then the volt regulator is defective. There is also a way to test the gauges, take 2 D batterys in series connect one side of the gauge to positive and other to neg. , in needle should move to full range with the 3 volts.
dave
dave
Last edited by daveengelson; Oct 1, 2007 at 11:40 PM.
Elder User
Joined: May 2005
Posts: 581
Likes: 1
From: Montana
FWIW- Being from the old school I've never had any faith in the electronic guages. always had to much trouble with them. everything i own has mechanical guages. if you cant find the problem that may be an option. a little tougher to install but at least they dont lie. Dutch
Posting Guru
Joined: Oct 2007
Posts: 1,144
Likes: 0
From: Sedro-Woolley, WA
I believe the problem is in the gauge itself. Though fairly reliable, resistance style gauges can age and change resistance rates and that can lead to a slight warming in the resister and further reading changes, you mention a fade in temp reading even after shorting it to ground. That wouldn't happen if the resistance was stable.
