okay so my 4runner started to do something funny the other day. the gauge would climb at a fair pace right up to the red zone and stay there for a good few minutes then drop back down suddently (regardless of outside temp, hills, city or highway driving). it would be fine for the remainder of my 4runner being warmed up, ie stoping to get gas or going to the store. so i checked under the hood and seen that my over flow container had overflowed.

ive replaced the t-stat and toped the fluids off now its doing the same thing but its not over flowing out of my overflow container. but now instead of the guage dropping suddently back down to normal temp it sits at the needle drops down a 1/4 of the guage sits there for a bit then will drop back down to normal.

is my guage hooped?

should i get a new one from princess auto (for those of you yanks its a cheap auto/farm surpluse parts store) and try it if it dosnt do anything then i can always take it back (love there return policy).

i have the money for a new rad, water pump, and all that i just dont want to spend it on that cause im a broke student and am saving up for a D.O.A. built 22re so yah it will be fun

what else can i do? what else could it be?

 

Sounds like a headgasket. Do you see bubbles in the radiator with the cap off while its running?

 

it overflowed your recovery tank then was fine the rest of the day...
then gets 'hot' drops a bit, then a bit more...
but after the first 'hot', it doesn't overheat?

check you lower radiator hose, that it is colder than the upper hose, and that it isn't collapsing when you rev your engine up.

 

I had an over-heating problem with my 87 Runner that sounds kind of like yours....if the gauge goes up to the red in less than 5 minutes of highway driving then you have a clogged radiator.

I also allowed it to cycle up to the red mark too many times and took out the HD.

Check for mud and debris clogging the air fins of the front of the radiator also.

 

Do yourself a favor and do some searching on DOA before you let go of that hardearned $$$$.

 

yah so i did notice bubbles in my radiator and my head gasket is blown also today going to work which is a 15 min highway drive, mt guage took longer to actually climb to the read zone. it stayed at the normal spot for a while before it climbed. it still hadnt droped when i got to work so i dont know.
spraying my radiator off right now to see if that helps a bit

 

I would bet money your Thermostat is sticking. Replace your thermostat and see if she's good to go.
If not have a leakdown test performed on your head.
peace

 

If you got a bad hg your getting air into the coolant system.. Unless its burped and all air removed you will get that wierd hot thing going on...

 

yha i have the new thermostat in there right now and it is still doing the same thing so this could be fun

 

I might be a little late responding to this, i haven't had a toyota do this, but when i worked for chevy, i saw this on a van. its a head gasket, or even something bigger, like a blown cylinder. you probably have power loss right? its showing classic signs of bubbles in the system, it tricks your temp sensor, the temp sensor doesn't know whats it measuring, sometimes just the air sometimes coolant, so it sends hot and cold signals to your gauge, and air pockets at the thermostat, so the thermostat opens and closes whenever it is hot, but with air bubbles, it doesn't really measure the coolant temp and the coolant could be boiling like crazy, its like a bad bleed job, thats a similar symptom. your car is definitely overheating, check for white residue at your tail pipe, which most of the times doesn't help, because we have our radiators filled with just water. if you know a smog guy, you can run the truck over and have him sniff your radiator for Hydrocarbons, you can buy test kits. you can also have your blower fan blowing full heat in the car, and put your hands up to the vent, and you'll get hot air for a while, then cold air especially if you live somewhere cold. do something quick, or else you will be buying a new engine.