mitcheljamespratt

Bought my 4 runner last week and its having overheating problems only on the first start. the temp gauge seems to be fine it starts at the bottom and slowly works its way up till it gets close to overheating i will pull over and shut it off and start it again and it will be fine i can drop it in 4th and tromp on it up a hill and it does not move untill i shut it off again. i just changed the thermostat yesterday i put in the stage 2 one made no difference at all in how it runs i ordered a new clutch fan and will be installing it soon since the old one has a little play in it but it wouldn't make sense for that to be the problem. so i'm out of ideas someone please help me all my fluids are fine and no cross contaminates also i ran the truck with the rad cap off so there is no air pulling into the cooling system so i don't know what else it could be

rworegon

What is the condition of the radiator and radiator cap? Dirt in the fins? Internal condition?

mitcheljamespratt

its only a couple years old and everything is in almost perfect shape few bugs stuck in it like usual but thats it

rworegon

Get the new fan clutch in and post up the results.

mitcheljamespratt

will do ill probably have time to get around to it at work tommorow

BigBluePile

iTrader: (3)

Yes. Also, make sure that it's actually been bled properly. Does it have rear heater? Make sure that's on too when bleeding.

Terrys87

iTrader: (1)

Below is how I fixed my temp guage issue. Like others and you have mentioned fan clutch, thermostat, and radiator. If you flushed the radiator with the Prestone kit, it will help but wont get the build up out. Take it to a radiator shop and have them to power flush it. It will look like mud coming out of it. I have to pull my radiator for my local shop to do it as he wont do it in the truck.

Copied...
A while back I was mentioning that my wifes truck water temp guage was going from half way to cold. I actually forgot about it until I drove it today and it did it again. I pulled the water temp sensor and it had green corrosion on the sensor cleaned them with a brass wire brush and then I cleaned the contacts that goes to the wire as well with electrical contact cleaner. No more problems. Stays just below half as it usually does. I knew it wasnt overheating, but still like having a guage. Another thing that helps with other issues is to pull your instrument cluster and just tighten up all of the screws in the back of it. Some have backed out over time and usually 1/2 to a full turn will tighten them back up.

Here is a picture of a dirty Temperture Sensor. I have seen worse. I chipped some of the scale build up off so you could see a difference.


The sensor sits just below the Cold Start Injector in the Intake manifold. Uses a 17mm deepwell socket and is a 5 minute job. Sits between #2 and #3 cylinder and use a brass toothbrush to clean. Not a bad idea to clean the other sensors as well such as Cold Start Timing Switch, Thermos Switch next to the CSI Timing Switch, and the sensor above the two sensors just mentioned.

mitcheljamespratt

so I changed the clutch fan out and bought new rad cap just cause and still hasn't fixed the problem might get the whole system pressure washed and it does have the rear system heater, thinking maybe head gasket too but i'm not losing coolant so I don't know I am almost ready to give up on it has been doing it less frequently now though thanks for the ideas guys