MG Car Repair: 68 b temp gauge, voltage stabiliser, temperature gauge

Question
hi i have a 68 B, the temp gauge will peg to hot almost immediately after starting the engine. water pump,thermostat,radiator,temp sensor are all new.the funny thing is the engine does not push any water out or seem to loose any water. could this be a wiring issue to the gauge? or possibly bad gauge? any help greatly appreciated thanks joel

Answer
I assume that you have a USA spec. MGB

What does the gauge read when the engine is cold, before you start the engine?  It should be on the Cold stop.  If it reads hot, then the new sender in the cylinder head is faulty.  You can check with an ohm meter.  Pull the Green/Blue wire off the sender and measure the resistance between the terminal and the side of the sender.  A cold sender should be around 200 ohms.  If it is much less than this, then the sender has an internal short and is faulty.

One other possibilty.  Have you replaced the gauge?  1968 was a change-over year.  Up to 1968 they fitted a 13 volt gauge.  From 1968 onwards they fitted a 10 volt gauge.  If you have the wrong gauge, it would give an incorrect reading.  If you have the wrong gauge, it is easy to fix.  Just get back to me.