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Jared D
Jared D, ASE Certified Technician
Category: Toyota
Satisfied Customers: 1914
Experience:  Shop Supervisor at County Fleet
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2003 toyota Sequioa is overheating. I replaced the radiator

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2003 toyota Sequioa is overheating. I replaced the radiator and thermostat . Not losing fluid anywhere , oil is clean. What's next?

Good morning,

The fan on your truck has a clutch that is supposed to allow the fan to free spin while moving at highway speeds, but run the fan full force a idle speeds. That fan clutch could have gone out. Does it seem like the vehicle overheats more when idling or when driving at highway speeds?

Customer: replied 3 months ago.
Not sure. My wife left the car on while she went into the store with AC on full blast on a hot day. Came out and AC was blowing hot. She drove it to my brothers (5 minutes) and parked it. When I went to fill it up with water, it just came pouring the the radiator. Replaced the radiator and thermostat, and here we are. Should I take it for a drive and see? Should I try running it without the thermostat in there? The top of the radiator is hot but the bottom is not. Same thing could be said about the upper and lower radiator hose, what's up with that?

I'd probably drive it a little and see what it does. It sounds like coolant might not be circulating if the top is hot and the bottom is cold. I've seen a handful of these engine have bad water pumps that will no longer circulate the coolant. If only the top is hot that means it's not flowing like it should and you already eliminated the thermostat as a cause for that.

Customer: replied 3 months ago.
Are we still talking ? Sorry, this is the first time I've tried out justanswers.

I'll be here for as long as you need for follow-up.

I come and go- I don't work directly for just answer- I run a mechanic shop- so I'm not always at my computer, but I'll keep checking in to see how the testing goes.

Customer: replied 3 months ago.
Thanks, I'm going to take it for a drive and let you know. Any chance I bought a faulty thermostat? Where is the water pump in this vehicle? How accessible is it?

It might be faulty. That's not very common though.

The water pump is below the thermostat housing.

Here is how you replace it:

Customer: replied 3 months ago.
Thanks. I drove it, it got hot fast. I'm going to try running it without the thermostat. Water pump isn't dripping or grinding at all . Anything else it could be?

That's a good plan. Pull the thermostat and see it it improves. If not I would pull the water pump. Usually the way they fail is the turbine blades on the pump disintegrate and no longer move the coolant.

If the water pump looks ok then the only other cause of an overheat would be a headgasket issue. A blown or leaking headgasket can cause an overheat in about 5 minutes.

I just remembered that the water pump is behind the timing belt on this engine. It's a good idea to replace the timing belt and components while you are in there.

Also, with the engine off try spinning the fan by hand. If it spins freely then the fan clutch is probably bad and might be causing the problem.

Customer: replied 3 months ago.
Thank you. I've got an appointment to get to, and will try those things out as soon as I can get to it. Is it possible that it's the head gasket if the oil and water are perfect? Also, what direction does the water flow? Upper radiator to engine through thermostat then lower radiator? Is that right?

It's possible to have a head gasket leak or a cracked head and not see and oil in the coolant or coolant in the oil.

It should flow from the top to the bottom. In other words the lower hose feeds coolant into the engine.

Jared D and other Toyota Specialists are ready to help you
Customer: replied 3 months ago.
Ok, well it seems as if the lower hose is not feeding coolant to the engine, and here is why I say that. I pulled the thermostat, and ran the vehicle on idle without AC on. After about 10 minutes, water was boiling out the reservoir, and the u
Customer: replied 3 months ago.
Sorry about that... The upper radiator hose as well as the top of the radiator was "burn you" hot, while the lower radiator hose was cool to the touch, as was the bottom of the radiator. It should also be added that there is a lot of squeeking coming from the from of the engine. At this point, it seems evident to you that the problem is the -------------------?
Customer: replied 3 months ago.
Ok, I also turned the fan by hand with the engine off. It didn't free spin, but I am able to turn in with minimal effort. I'm guessing that if the fan clutch is bad, it still doesn't explain the lack of circulation in the engine though.
Customer: replied 3 months ago.
Praise The Lord!!!! It's fixed! Thank you for all of your help!

Sorry, I was out working on stuff all day.

I'm glad you got it sorted out. What did it end up being?

Customer: replied 2 months ago.
There was an obstruction inside if the lower radiator hose. The obstruction was removed, and all is well. Should I be concerned about the fan?

How weird. It sounds like you got it nailed down.