Strange electrical thing

[rblong]

You guys are going to think I lost my cookies, but I have been working on some upgrades to my cooling system so I have been running a lot of test on water temp, fan CFM etc. In other words I have been spending a lot of time watching digital meters and the water temp gauge! I noticed that when driving at night sitting at lights that my temperature seemed to creep up (20 degrees - up from 195-210) and my oil pressure falls off (5-10lbs) . I assumed the motor was getting hotter causing lower oil pressure but it is a night and cooler than during the day - and it don't do it during the day! This weekend I was changing stats, starting to fab shroud and decided to run tests, of course it is day so I don't have the lights on. I am watching temp gauge and a digital thermometer, oil pressure gauge etc. and all great with fan cycling on and off as it should. I think what the heck is happening at night - I turn on the heaglights and guess what - the temp gauge rises 15 degrees and the oil pressure falls 5 lbs. Now I have a digital meter going and the actual temp is not changing. I am thinking that maybe I have a voltage drop with lights on so I check it. Sure enough I am running 14.5 VDC with no lights and 14VDC with. Could this cause it? I am running all VDO gauges. Now mind you this is early in the day and I hadn't had anything to drink but coffee yet!!! Too weird for me.

Bruce