Wrong Temp Sender
 

I've got a rebuilt engine with vortec heads. My temp reads really low, but the hoses are hot and the t-stat opens just fine. I think I ended up with the wrong sender. The original was too large, so I got the one for the later model. Anyone got any tips?

I have the opposite problem on my 69, the temp gauge reads way too high. I think you can hook up a variable resistor in place of the temp sender and adjust the resistance until your gauge reads "hot", then go to the parts store and find one that has that resistance at 220 degrees. I haven't done this yet, but it was recomended by a trusted mechanic, so I'm assuming it will work.

Sometimes its just because it was mounted different. Newer engines had the sensor on the intake manifold, mine was mounted into the head. So when its running hard the temp shows a steady climb til I let off it. I'm going to switch it to the manifold so its more accurate.

HG

There is a spot on my manifold where I could put in the original sender. I'll see what that does.

manifold

I have exactly the same problem ---- installed new gm crate motor 330hp and can't use factory sender because of wrong size.. If anyone has or finds the correct sender I'd sure like to know it. Someone about 6 months ago was mentioning a Volvo sender that might work or maybe some type of inline resistor.. Any help would sure be appreciated.

I had that problem when I installed a crate 350 in my '71 GMC. A mechanic told me to install a resistor in line with the green wire, but it never worked. I finally went with an Auto Meter mechanical water temp gauge. Works great.