I recently bought a 1989 740 GL with 50K miles from an elderly friend of my mothers. It is in very good condition but I have two minor problems. The temperature gauge is erratic. Sometimes is will start to rise appropriately when the engine is started but then drop back to zero. I suspect a poor contact somewhere. Any advice on what should be checked?

Also,the car runs very smoothly when driving and shifts correctly (AW70 transmission with O/D) but when I stop at a light and leave the car in drive, there is an excessive amount of vibration resulting in rattles. If I shift into neutral the vibration stops and resulting rattles stop. The idle seems appropriate - approx 800 rpm showing on the tach. The only thing I can think of is tired motor or transmission mounts. Any ideas?

This is my first message in this forum. I am a longstanding fan of Volvos having bought my first 544 in 1963. Since then I have had another 544, an 1800 ES, a 122S bought new and a 240 wagon bought new. This 1989 740 pretty well rounds out all the post-war RWDs for me. Unfortunately the newer FWDs have moved into a luxury bracket beyond my means. I have enjoyed the good information I have found on the Brickboard - thanks for the service.