OK, so this may be a stupid question, but here goes, the temp gauge in my ’49 cad (original 6v with a Runtz) quit working, so I thought I’d install a manual gauge to see what actual temps the motor is running at. So I installed the temp probe in the back of the intake manifold, where the old electrical sensor was, and now it is overheating...and never did before! Now at 50 mph it’s at 200 (new 195 thermostat) when I slow down in traffic it climbs to 220, and higher if it idles very long. Then pukes into the overflow when I cut it off, never did this before. I can’t see how that temp probe could be causing the problem, but whadda’ I know. The engine is a ’77 Olds 350 with a mild cam, and hot ignition, otherwise stock, and is running the original ’49 radiator that has been flushed etc, and a big electric puller fan that will hold a shop rag up to the radiator, and it runs all the time. Any ideas/info would be appreciated.