Ok, this is a follow-up question to one that I recently posted and was graciously answered (perhaps these are relatively basic questions, but this being my first Volvo and my making the mistake of purchasing a lousy repair manual leave me in this current predicament).

The Check Engine warning light went on the other day on my 1990 740GL Turbo, apparently as a result of a leaking lower radiator hose. I've replaced both the lower and upper hoses and refilled the system with antifreeze and, despite no leaks, the warning light remains on.

I followed through with the recommended response to retrieve the code from the OBD per the FAQ's instructions and then reset it, however, the code (Socket #6, 224-Engine Coolant Temp Sensor signal absent or faulty) came up again. Here's where I'm looking for guidance. First, does these sensors typically go bad when a coolant leak occurs or is this just a coincidence. Second, where is this part located (I assume somewhere on the engine block?) and how easy is it to replace? Any good suggestions for where to buy this part or should I just bite the bullet and go to the Volvo dealer? Finally,any good recommendations for a repair manual (that hopefully remains in print)? Thanks.