this last Monday my car over heated. it was quite the experience as water and steam blew out from the vents of my hood. took me several hours of short driving to make it back home. so i get it home and buy a new oem radiator. put it on. burped the system as advised and in 5 min my car nears the over heat on the temp gauge. i turn the car off and get out to feel the hoses. the engine out hose (hose going to the top of radiator) is really hot while the one from the bottom of the radiator isn't hot compared to the top one at all. so i'm thinking maybe my thermostat has gone bad. weird cause i just replaced the cap and the thermostat about 6 months ago, and with a fail safe one at that. if it goes bad it will stay open. so I'm a bit stumped and my fans aren't turning on. when i turn on the ac the fan bolted to the ac compressor does but not the radiator fan. so i bypass it by pulling the plug to my cooling fan switch and yay the fan now turns on. all the time but never the less it means my sensor is bad. so i let the fans cool my radiator down for a while and get back in and start the car. car dosent over heat now but it is irregular. it will sit at 2/4's the way there, and go up to 3/4's and drop back down to 2/4's. i turned on the heat and even with my car warmed up it blows cold, im guessing this is because my fan is on all the time. i also sit in the car for a while and i noticed my air to fuel gauge isnt acting normal. it usually will swing back and forth the full range of optimum, now its swinging back and forth but in a very small area in the optimum range. as if i was cruising at 45 in 4th or 5th gear. so i wondered if my fan relays or fuses could be bad, i open up the fuse box and the efi main relay is super burning hot. painful to touch for less then half a second. i go back and feel my lower radiator hose and it is now hot so that rules out the thermostat.

so far....
the cooling fan switch is bad
water pump could be bad?
my head gasket might have blown but i checked my dip stick and saw no coolant mixed with the oil.
is my efi relay supposed to be that hot?

sorry for the long post. suggestions? guesses? all appreciated. use my painfully long and descriptive post to help me narrow down the possibilities.

 

Did you change the thermostat?

A blown head gasket need not cause water in the oil. You can purchase a Block Test kit that uses chemical to test for exhaust gases in the coolant.

Exhaust in the coolant can cause overheating, thermostat operation problem, etc.

 

i changed the thermostat and the cap about 6 months ago.

update. just bought a new radiator fan switch and installed. fan still dosent turn on. im gona buy and replace the thermostat tomorrow because upon 2 min of start up i noticed the upper radiator fan is bloated to hell. looks like it's about to explode. so i took my thermostat out and i boiled it in water to see if it would open i lil before boiling point. it did... im so confused. with the thermostat out i turned on my car and took note that the upper radiator fan was once again back to normal (not bloated) so there's nothing blocking the water other then the thermostat. i checked my relays today for the fan as well. everything works fine. any ideas on why my fan wont turn on unless i unplug it from the radiator fan sensor?

 

No, your fan switch may work fine. It is not activating because the water temp in the bottom of the rad has not reached a high enough temp. But you can test it by putting it in hot water and doing an continuity test. You may just have air in the system that created an air lock. Jacking up the front end as you fill the rad helps to vent air. You should also have installed the stat with the bleed hole at the 12 o'clock position.

 

it was indeed the thermostat and the water on the bottom wasn't heating up. fan turns on now! but my head gasket is bad =(. oh boy... my back is gona hurt for several days

 

so update guys! fixed all the over heating issues and i started her up last week. but now it bog's really bad and runs super lean. i at first thought it was my head gasket. checked oil and no water in the oil. i flushed the radiator and no oil in the radiator. so i did a compression check just to be sure. roughly 120 psi in all cylinders. so i got to work on the fuel system. changed my fuel filter but to no avail. so i was thinking maybe the egr or my injectors, spark plugs and wires. i figure i'd start from the cheap side and hopefully luck out. changed the spark plugs. the old ones looked nothing out of the ordinary. my wires upon inspection looked ok too. changed them anyways and horray! its running normal again!

so i got to thinking. my celica has 180 thousand miles on her plus some, cant remember off the top of my head. she was my daily driver till about 2 months ago when i bought a used 05 camry (WHOOP!) and since then i've been to a few auto crossing events and only drove her as my weekend warrior. she's goten old...... so i ordered a new 5sfe for $800 with a 3 month warrenty! pics will be coming soon. some questions though. i ordered a rev 1 5sfe so i dont have to pull the rev 1 ecu and the harness out. the engine is a 93 5sfe with roughly 98 thousand miles on it. compression tests were roughly 150 in all cylinders. did i pay too much? this is the first engine i have bought.

 

Nah thats not too much, but as advice, never buy an engine claimed to have been rebuilt if the owner cant provide reciepts from a machine shop and if they said they did it themselves call bs, laugh and walk away or ask them to show you what they used to machine everything and ask them if they plastigaged the crank bearings. As for your fan troubles, i would of said hell with the sensor, put a toggle switch in so you can turn it on yourself when its gettin warm

 

I think problem is in the thermostat

 

I am having some overheating issues as well. It gets hot then I refill the radiator and the overflow to the proper levels and just all the sudden in 2 til 10 days it will run hot again. I took it to my mechanic and he says that is is leaking in the conbustion chamber. He told me he put a pressure test on it all night and there were no signs of an external leak, therefore it had to be internal.

He said I had two options; Sell it before it dies; or rebuilt the top of the motor.

Any suggestions or has anyone had the same problem?

HELP I don't want to lose my Toyota....

 

If that is so (head gasket) then after it runs hot and you shut it off to let it cool you should get water in one or more cylinders. Remove the sparkplugs to see if water in cylinder. Compression test will also show which cylinder the head gasket is affecting. Car should be running like crap as well.