I'll try to make this short! My 92 740 wagon (non-turbo) was experiencing intermittent no-start problems. Volvo tech could not figure it out and thought it was internal engine damage.I took the dog-gone thing home and proceeded to remove and replace the cylinder head.(took me 6 months with help from Brickboard and others)Also replaced gaskets ,plugs, wires, rotor,fuel pump relay,coil wire,timing belt.Well it started right up but I have a check engine light. code 123. I replaced the temp sensor to the gauge because the gauge wasn't moving.Now after reading the FAQ section for the 8th time I realize that I should maybe replace the 2nd temp sensor!If I do that ,do you think the cel will go away? Also the electric cooling fan does not come on and I don't seem to have a fan relay to check-only the radio noise suppression .It doesnt also operate the fan,does it? I should mention that I could only hand-tighten the sensor I put in,and I had to cut the connector off an old 940 and splice it on with electrical tape.I mention this because I know the engine will make adjustments based off what the gauge sends it. I feel like all these symptoms may be related and it would be great if I could find the culprit.Sorry I don't have a pointed question but I've done so much on my own I'm just looking for some fresh viewpoints and any other advice some of you kind folks can give me. I'm a 60-year- old gal and I've been under the hood so much I'm beginning to call left 'right' and right 'left' ! :) Thank you so much guys (and gals).