Flow through the radiator could be obstructed by scale built up in the radiator itself. Be sure to check for that.

 

I tried to replace the thermostat today. Well... after one stripped bolt, radiator fluid all over the driveway, and tools flying accross the yard.. it didnt go too well. i will try again tomorrow with a better socket.

I also happened to notice that my radiator cap is broken the spring was actually sitting inside of the radiator and i removed it. could it be posible that a faulty radiator cap could reduce the cooling system pressure and cause it overheat and nott flow through the lower line? or could it be the thermostat and the radiator cap both being faulty?

 

Yes very possible the rad cap is the issue...I think Jim or PA asked about that.....without pressure in the system, the boiling point is lowered quite a bit.

I think the bolts are a 10mm socket.

 

yes i thought i recalled someone mentioning that earlier in this post. it appears to be just the spring that has broken off. im still no quite sure though because theres still the issue with the cold lower hose and the engine side of the thermostat being around 200 while the upper hose and radiator are boiling and the temp guage never goes over half.

 

You could have a couple different things here. Bad radiator cap can cause it to boil over, with all the visual cues of overheating.

Still, the cold lower hose doesn't sound like a bad cap. That can be caused by a blocked radiator.

 

im not sure its a blocked radiator. when i disconnected the lower hose it drained the radiator quite quickly. but still the temperature reading around the thermostat make me to believe it may be the thermostat as well. i found it to be over 200 near the engine side of the housing and about 90-100 on the hose near the thermostat housing, so perhaps the thermostat and cap?

 

Yes, it could be that. You'll drain at least some of the antifreeze when you change the T-stat. Look inside the radiator and/or inside any other water passageways & check for scale build-up.

 

Fluid looks damn near new. which it should be because there was a reported front ennd collision in 2004 so unless the owner then put around 100,000 on that new radiator then it should be still good.

Whats the probably that all the problems could be just a defective radiator cap?

is it more likely a combo of t-stat and cap or could that cap be causing loss of pressure in the cooling system deeming it useless

 

I'd say cap and T-stat. I don't think a bad cap alone would cause the cool lower hose.

 

so im thinking i should replace the stat before putting the new cap on so it doesnt cause any other problems when it gets hot. i have no idea im just assuming that sealing the radiator will cause the pressure to get very high if the engine overheats again.