hey all,

The Story:
last winter my 1994 toyota pick-up (22re) started surging at idle, about a month later my engine started pouring steam out of the radiator. engine wasnt getting hot prior to steaming at all (according the temp gauge). i replaced the radiator cap and re-filled radiator with proper mix of coolant and water.

The problem was fixed completely until this winter (about the same time, when the weather starts getting cold), same symptoms, surging idle and then a month or so later, i was driving to work and steam started pouring out of radiator.
so what could the problem be?
i dont have a fluctuating temp guage (started getting hot becuase i had to drive it the rest of the way to work, but never got in the red.)

oil is clean and not burning.
no smoking exhaust.


thanks in advance for suggestions!

 

Have you replaced the thermostat?

 

OK,

today i finally got the time to work on my truck. what i did was replace the thermostat/gasket. i fixed a leak in that hose next to the housing (bypass hose?). but im still having surging idle. when the radiator cap is off the surging idle is directly related to surging in the coolant. the coolant is surging out the cap in time with the surging idle. If i put the cap back on pressure builds in the radiator exiting the cap as steam. its not circulating properly it seems. what is the best way to determine if my coolant paths are clear (in the motor). all hoses are clear going to the overflow tank but no coolant is going there.

the only thing i can think of is that the waterpump is having to work harder to push coolant and making the engine idle surge to power it?


any ideas?
could a bad radiator cause this?
there are some dented fins on the fan side but water flows thru freely when flushed.

 

...bump

 

hmmm, strange...

but the coolant is going to fluctuate with the RPMs if the caps off; every time the RPMs jump up the water pumps speeds up, so it'll push the coolant accordingly. that at least means you're water pump's working

have you burped the system to get all of any trapped air out?

 

what is the best way to burp the system?

all ive done is let it run with the cap off until no more bubbles.

 

do just that, but try to pull the truck onto ramps or something to get the front up higher; you want the rad cap to be the highest possible point, and the incline will help the air rise to it

 

you can also disconect your heater core hose to, thats what i did