200 Jumps To 240+

[popjohnson]

I recent bought a 84 ttop GN and i noticed that when I get on it the temp raises FAST!!! For Example I jumped on it for about half a mile and the temp went from 200 to 240. It has Electric Fan, and a new 180 degree thermostat, mechanical gauge so it accurate any suggestions?

 

[3point8]

High temps

I experienced the same problem on my 85GN. Had to revert back to the mechanical fan. The temps are back to 180 max.
I think we need either a larger radiator or a dual fan unit, probably both. On my car there is only something like 19"x21" area to install the fan(s).
Peter

 

[conn84gn]

The 84Gn has a smaller Radiator than the 87
87 will fit, just move the rubber mounts to the outer postion
GM V8 radiators from 87 will also work and are cheaper but you may have to use a external tranny cooler.
I can't remember if the tranny lines are on the same side.

 

[garyk1970]

after the previous owner blew the head gaskets in a 85 gn i used to have,i found it was caused by a stoped up radiator,installed a new 3 core radiator,largest electric fan that would fit,adjustable temp control,160* thermostat,(all above bought at autozone)car ran the best it ever had for the three years i owned it with no cooling problems.

usually if its not the guage,the radiator will make the temp rise as fast as you described.