I too gave my engine a bath with "Gunk' yesterday (87 5k CST) and guess what? the temp light stays on! All i can figure is that I got water in the sender. I believe there are two senders, one for water level and one for temperature. Is this correct? if it is it's the level one that's affected. I think the sender is a pain to get at, but i haven't really tried yet. Anybody have any ideas?? Steve