'87 245 5sp. I just bought this car and the previous owner told me the car has been doing this for a while. After start the temp gauge needle will climb into the normal range and then fluctuate between the normal range and the line just below the red, danger zone. I'm pretty sure this is an indication problem. The cooling system appears to be operating normally. There is one small leak but it seals up when the car is warm. The coolant level reads normal at the reservoir. I had an extra gauge so I replaced it, but it didn't fix the problem. The car has a lot of miles, 251k, but that shouldn't make any difference. Any ideas on what could be causing this? Thanks in advance to all.

Jim in CT
85 245 202k : 87 245 251k : 93 945 97k : 95 855 133k