overheating

[B-FISH]

temp goes up and drops say if im on the freeway, i took a look at the thermostat, i noticed that the air bleed was at the bottom, do u think that may have caused a really bad air pocket??? i think the thermostat was ok....
im really hoping it isnt my water pump....

or my radaitor.....

or anything really dam expensive....

 

[chilkoot]

the thermostats are designed to fail open, from my experience and what i've read after it fails your temp gauge will stick at about the first tick marker. the jiggle valve is supposed to be at the top, try flipping it and seeing if that helps.

I don't really see how a failing water pump could cause temp fluctuations; I'd think the most common failures for it are either coolant seeping or the pump completely seizing.

 

[B-FISH]

Thanks For The Reply, Im Really Thinking Its Not The Thermostat, Because My Lil Tank Is Usually Low, But I Bypassed All That And Put Coolant Right Into The Engine, Drve And Checked The Level And The Coolant Was Being Pumped Back Into The Tank And Actuall Overflowing Witch Makes Me Think Its Not Getting Through The Thermostat.....does This Make Sense To You Too???

 

[B-FISH]

hey, i jus threw in a new thermostat and filled up on fluids and it seems to be running fine again. i think my thermostat was sticking or opening at a higher temp that it was suppossed to....because my car got really hot and i pulled it out and it was the first time i'd seen it opened up tha way it should be, but none the less i put the new one in because the ols one looked kinda old n beat down, so i thought i'd mite as well do it now...\

but ya its runnin like a champ again...thanks for the help...

 

[Nick M]

Thermostats stick closed. They have wax inside that needs to heat creating an opening.

 

[chilkoot]

Thermostats stick closed. They have wax inside that needs to heat creating an opening.

this contradicts what I have read here about the LS thermostat and my own experience, are you speaking specifically of our cars or thermostats in general?

 

[1uzvl]

They can do both,if replaced many that have failed either way.Although most seem to be stuck partially open but still work(havent really failed)but replace them as they then circulate water when cold.

 

[sideshow]

i ahve found std toyota 1uz thermostats have a small hole

a cheap aftermarket here in australkia have abit bigger diameter in centre

i have bought a trd 71 degree thermostat and it has big hole so more water flow then i drilled tiny holes round outside to get better water flow

i tend to think in our hotter weather the water flows to slow thru enigne

this does help abit but fitting an alloy rad cured 70% of my heating probs

 

[UZZ30-Québec]

not all the thermostats are designed to fail open.

drilling holes in the thermostat will cause your engine to have a longer warm-up time.

there are "high flow" thermostats available but with a stock engine you don't really need them. before drilling the thermostat, i'd double check my fans and radiator for efficiency.