Topic: quick radiator question

[JoeWelder]

im thinking i need a new radiator but i want to make sure.....usally you can run a vehicle with the cap off and its fine, but after a few minutes, mine will start flowin out the top. my truck did sit for a long time (years) so im thinking its cloggd up with  ive washed it out with a hose but its still doing it....also a guy at work said it could possibly be a blowin head gasket??

[Rocksurfer]

thermostat can cause that.

[JoeWelder [OP]]

i thought of that....so i took it out, but its still does it

[Rocksurfer]

Does it run hot or normal, if it is running hot may be the pump. Usually if it is a blown hg it will do it from start up on.

[79coyotefrg]

pull the thermostat and run it without one just to see if it forces the water out, if it does   you have a blown head gasket

[yotabj]

Have a radiator shop clean it, I bought a used rad. for my s10 and flushed it many times and never got it clean. I took mine and he said it was prolly the worse radiator he had ever cleaned.

[JoeWelder [OP]]

it got real hot when the thermostat was in, even with out it in, after about 20 seconds of starting it, it start flowing out, if i gave it more gas, more comes out....i also replaced the pump

[JoeWelder [OP]]

i did run it for about 15 minutes with out the thermostat in and it defintly helpd, it didnt get nearly as hot

[93tonkatoy]

All of this can be done easier without the t-stat installed!

To tell if it IS your head gasket, start with the engine cold, fill the radiator, disconnect the overflow tube from the overflow tank, then crank the truck an let it run (and rev the engine hard a few times - not for high revs, just quick full open/close throttle bursts) for 45 seconds to 1 minute (not enough time to get the coolant hot). Watch what comes out of the overflow. If you only get small drips of water, then the coolant is expaning as it heats. If you get "geysers" of coolant coming out, especially when revving the engine, possibly followed by air, then your HG is blown. Immediately after you shut off the engine (BEFORE THE ENGINE GETS HOT) open the radiator cap. If you get pressure release, it is the HG.

Also, with the cap off, and the engine running, check to make sure you have coolant flow across the radiator. If not, check the radiator core and the water pump.