So a few months ago, I had some sort of coolant leak. Turned out, the temp sensor died, causing the fans not to come on, car overheated and burst the rad.

Took it to a mechanic, they replaced the rad and the sensor as well as a new radiator cap. Car has been running perfectly fine since then (except for a leaky valve cover gasket, just changed it, should be unrelated).

Today took the car out for a spin, was running fine, and then in traffic BOOM, the lower rad hose burst AND the cap popped off the overflow, spraying coolant all over the engine bay. If it makes any difference, the overflow tank level is ABOVE "FULL HOT"

Any idea what could have caused this? Seems a bit weird after all the parts that were changed and how well the car has been running.

I've been trying to change the thermostat, but the bolts are rusted shut. Tried soaking them with WD40 multiple times, tried using a breaker bar to get them off, but they won't budge.

Also, I felt the upper hose right after, it was warm, which AFAIK means the thermostat is letting coolant through.

 

Mighta just been an old hose that shoulda been replaced already...

See my signature. Sometimes you can out-think yourself.

Thermostat bolts are notorious for getting frozen into the manifold. Best plan of attack is probably to go ahead and break them off; drill them out, GRADUALLY, starting with like a 1/16" bit or thereabouts, CAREFULLY centered on the bolt and drilling STRAIGHT into it; increase the size, like to 1/8", then ¼", then to 11/32"; then Heli-Coil the manifold once you get all the fragments of the stud out.

What is this "mechanic" thing you "took" to? Sounds like that might have been part of the mistake? Maybe you shoulda just replaced the hose in the first place?

 

So I had a new water pump and thermostat and hoses installed. I read a lot in these forums, and the 180 degree thermostat seemed like the way to go. Can someone please confirm if this is a good setup?

-Completely stock 305 TBI

-Stock Radiator

-180 thermostat

-Stock SINGLE FAN setup ('89 Formula with AC....is it supposed to have dual fans?)

-Recently replaced temp sensor between Cyl #6/8 TS147T


Does all of this jive?

 

No reason not to use the stock temp thermostat but the 180 is probably OK.

The temp thing between #6 & #8 plugs is the fan switch. The one between the #1 & #3 plugs works the gauge. The one on the intake manifold is what the ECM uses.

AFAIK the TBI cars only came with single fans.