Coolant temperature sensor location

Back rt corner of engine by the egr cooler

 

Sounds like your cooling system is clogged,maybe someone put some engine headgasket repair stuff in your engine

 

It sounded like the engine with the blown gasket got replaced, and this is about the replacement. (I guess it could be a used replacement that somebody else put gasket gunk into, but that's kind of speculative.)

That is an odd sound from the w/p. It sounds as if it is struggling to start. Perhaps it's getting inadequate voltage, might indicate damage or corrosion somewhere in the connectors, wiring harness, relay, or fuse contacts feeding it. A problem like that would be common to all the pumps you have installed, and could also be behind the failure of the old engine's head gasket in the first place.

Caution: I'm relying on memory here: I think the water pump is fed on 12 volts (unlike, say, the air conditioner, which gets 200+). If I'm right, you should be able to troubleshoot as with any other 12 volt device in the car, no worries. If I'm wrong (and the wires feeding it are bright orange), then ignore what I'm writing below (it'll have to be approached much more carefully).

If you have Techstream (lots of threads here about that), you can command the w/p on and off without the engine running, so you have less other noise and distraction while checking out the pump. A multimeter with fine-tip backprobes will probably let you test the voltage right at the pump connector when you have commanded it on. If it is not plugged into the pump, probably you will see 12-ish (close to battery voltage) when commanded on. The key will be watching whether it stays that high, or how low it drops, when the connector is plugged into the pump (hence the need for backprobes).

The back of the connector probably has rubber seals where the wires enter. These seals are usually crimped into the terminals at the wires' ends, meaning you shouldn't try to slide the backprobe in through the central hole in the rubber where the wire goes through—that would end up piercing the seal. Try to sneak the probe in around the outside of the seal (can be tricky because the connector housing might have a step in it beyond the seal).

If you see a voltage that drops (you might see it alternating between close-to-12 and something lower, in time with the weird sounds from the pump), then it's just a matter of following the circuit back in the direction of the relays/fuses to see at what point the voltage drop becomes a thing. Then fix that.

By "following the circuit" I don't mean physically trying to trace the wires back, they're all wrapped up in black tape and stuff. You'll want access to the wiring diagram at techinfo.toyota.com to know where the various intermediate connectors/fuses/stuff are located, then just test there. You only need to start unwrapping tape if your results seem to point to wire damage between two points where you test, but in that case you'll probably see some obvious gash to the harness from driving over a rock or something, and you'll have a good idea where to untape and repair.

By the way, the wiring diagram is also what will tell you which poles of the water pump connector are the power (if there are more than two). I bet it probably has some monitor wires also, to confirm it's running. In fact, you might check the Techstream live data to see if shows water pump RPM (I don't remember offhand). That could also help you see whether the pump noise has to do with trouble starting. (Any readings in Techstream might not look perfectly in time with the pump sounds, because Techstream is reading them from the car's computers with a bit of delay.)

About the temp sensor, that does sound like a separate issue, possibly overlooked in the engine swap? Using Techstream (or even just a ScanGauge, Torque app on a phone, or really any old OBD-II reader, because coolant temperature is a standard item to read), you should be able to just watch your coolant temperature while your engine warms up. If it looks reasonable, maybe the sensor's ok. If it looks stuck on some unlikely reading, then you'd dig in to make sure it's connected, and the connector's not damaged, etc.

-Chap