modulater

The coolant light supposedly comes on when you have low water but they always seem to play up. A trick I know is to remove the cap and run a smear of vaseline around the seal. sometimes the seal dries out and when you put the cap back on it snags and causes the system to loose pressure and your coolant evaporates away and the level drops. its why you put a smear of oil round a new oil filter seal, sounds weird but it helps it seal and stops it snagging.

No 1 is always the timing belt end of the engine. and it is indeed 1-3-4-2