My 86 Trans Am has been sitting for about 3 years now. It has a cooper radiator in it. I installed a 160 stat and a fan switch, which doesn't work the fan stays on all the time now. Anyway, it pinned the tempature gauge today while sitting in traffic. I assume the water pump is working, because with the cap off the coolant is rushing in good from the heater hose. Do you think it just needs a good flush from sitting so long?

 

Brian, when it pinned the gauge did the reservoir also boil over and make a lot of steam? It not, your gauge sender or the wire on it may have a problem, it'll pin out if it gets a no-resistance ground.
If it is boiling over, give everything a good flushing, both ways. Squeeze the upper hose while it's running when the stat's open and then release it slowly, you should feel a surge of the coolant come thru it. If you don't feel anything or not much, your pump may not be working enough to create the needed pressure.

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DR Stevens
1984 Trans Am 305HO L69
sucks gas, hauls ***
1991 Firebird 305 LO3
for days when I need a/c

 

I agree with eightTfourTA but you might also want to drop a 180 in there. In some cases a 160 can stay open all the time and cause the car to overheat or in others it can cause the car to stay cold. Flush the system check the water pump and change the termostat.
GL SSC

 

The overflow didn't boil over, but it was filling up more than normal. I will try the hose thing, but I am guessing it needs to be flushed.