The V8 Owners Forum -

Just got an infra red thermometer and thought i would check the temperatures around the engine, with engine running and fully warmed up
On checking the exhaust manifold/head flange i found that they were all between 80 - 100 degrees C, except No 6 cylinder which was 180 degrees C. Should i be concerned about this variation? Engine is new and not fully run in yet.
Also the temperature drop across the radiator between inlet and outlet is 10 degrees C. Does this sound correct?
Many thanks.

Can you check your plugs? If there was a big difference in temperatures I would expect a visible difference in your plugs.

Infrared thermometers work by measuring the thermal radiation emissivity of an object and shiny surfaces can mess this up.

Is your manifold a log/cast type or tubular separate? Dull or Shinny?

For more accurate readings you're supposed to stick some black tape/paint over the measurement spot although I don't know how this would work on a hot manifold.
If log type I would struggle to see a temperature difference that great could happen and would suspect the measuring system error.

I have separate tubular headers and they are quite a good tool for telling which cylinder is down, by touching them (very quickly!)

Tom.

Maybe No. 6 is blowing slightly.

Chris.