I noticed my senders are backwards on my flathead.The two prong is on the passenger side and single on driver's side.The original wire to gauge has been replaced with a new wire and the gauge of wire is a lot smaller than the original.Would this make any difference in the temperature reading on gauge?

 

should't make difference which side, they do same job. are you unsure of temp in engine? wire should be consistent with rest of harness, so if suspected of weakness, replace with maybe 14 or 16 guage wire. power goes to one of two posts on double post unit then crosses over to other guage.. i installed seperate units with seperate guages on my truck simply because flat 8's are basically two 4cylinder engines when it comes to cooling. petey shoes

 

Not likely, there's very little current involved. Are the sensors hooked up properly?

 

Yes,everything is hooked up right.I just thought maybe that replacement wire was to small and was causing a bad reading on gauge.I have new radiator,NOS gauge,160 degree thermostats,6 blade fan and gauge still likes to hang at third mark or close to "H"???

 

i have 2 stock senders that read as yours from start up. i know the engine wasn't hot, you could put your hand on the rad hoses and near the block, no inidication of heat. i bought an aftermark guage and put it in place of the two post sender and left the single sender (the two post sender is just a switch for overheating, the single pole is the proportional temp reader). when i start it the old guage goes to the same sport, 3/4 way to hot when the engine is stone cold, and the aftermarket reads exactly as expected. i know i don't have reliable temps from the original sender but i know both sides seem the same temp. i've considered buying a replacement sender or a second temp gauge. dick r.

 

Dick, I just took a look at your gallery. We have similar ownership stories. I bought Willard my 49 f-1 from a friends father also in 1977 (but paid $500) in California. Drove crosscountry in 1978 (running a nailhead buick) flat towing my Model A Vicky. Was a daily driver until 1986 and I am in the revival process. I never had Willard with the flatmotor and am working on the dark side.

 

I like pety shoes idea of a split circuit. Any time one sensor can affect the outcome of two readings, it's time for a mod. I would find the correct guage wire and replace the odd one you spoke of. The temp circuit readings are based on resistance change. I don't have a flathead but, I would pull both sensors and using a hairdryer and a meter check the overall resistance and smooth resistance movement through the range of change. Any resistance reading in ohms reflects a circuit completion.You need to know if they are a match or close to the same. Any circuit according to the formula V or E = I x R when you change resistance (wire size) you would change the circuit. Some may change greatly and some not so much. When they get old, time to replace them. Have a great day,chuck