So I just replaced the thermostat, and heading to the mall today notice it was overheating again, this time it was just a little over the middle on the gauge, what could it be? Thermostat, Water pump, and radiator cap changed. I also noticed that when it was above the midpoint, I'd put the heater on and it would bring it back to the normal point where it usually is at.

How many miles? This is important.

I'll chime in here.

Turning the heater on actually helps cool the engine by pulling heat out of the engine bay.

Why it is overheating...
- Pink milkshake could be happening. Did you look at the coolant; what color is it?
- Head/gasket issues

I am currently facing a head job on my 97 w/199k miles. I will know more on Monday. IMO if your truck is overheating, I wouldn't drive it around. Spend some time calling until you can find a local should that specializes in Toyota engines.

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Good luck!
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Sounds like your radiator is full of rust and oxidation. you might have to flush your coolant system with some sort of cleaner. If it doesn't improve, then you might have to replace the radiator.

I don't think it's the head gasket, at least I hope not. I don't have any of those symptoms. No loss of power or white smoke out of the exhaust. I'm going to have my dads shop check it out, hopefully it's just the radiator...

Might as well get a $106 koyorad from amazon and flush your old coolant out. I agree with singtoe as rust could have possibly stopped up enough of your radiator to create problems.

Lets look at what it could be and eliminate what is likley not the problem. There are three primary reasons for an engine to overheat: Insufficient water flow, insifficient air flow, insufficient cooling ability, or mechanical malfunction related to the engine.

Insufficient water flow

This could be caused by several things. The water pump might have a bad or worn impeller (with a new water pump, this is unlikely). The thermostat might be malfunctioning (new thermostat and the fact tha tmodern thermostats fail in the open position = unlikely). Build up of contaminents in the cooling system, such as rust or viscous fluids (likely). High probability.

Insufficient air flow

Only a couple things here. Fan not working correctly (fan clutch may be out). Radiator coils may be clogged (always possible on an old radiator, if this is the case, clean it with condenser cleaner for air conditioning units). Shroud may not be intact (this should be very easy to check). High probability.

Insufficient cooling ability

Given that the load that you are moving has not increased significantly, this is unlikley. This happens when the engine is being "lugged" and is not spinning fast enough to handle the load placed on it. Low probability.

Mechanical Malfunction

A few things here. Old oil or contaminated oil will create more heat within the engine as a result of increased friction. Head gasket malfunction can also cause this. There are others, but they are pretty unlikley given your description of the problem. Low probability.

Just came back from my dad's shop and they said it was the freeze plugs? They quoted me $120 parts and labor said it was about a 3 hour job. Does this make any sense? I have no idea what those are lol.

Freeze plugs going bad would allow coolant to leak out and a loss in system pressure which will cause overheating. Have you noticed any coolant loss after replacing the water pump and thermostat?

so your dad owns a mechanic shop or do you mean the shop your dad takes his car to.

if that shop cant diagnos it and if it isn't a toyota specialty shop I would try to find one. you are in east LA correct? thereis probably a toyota shop that focuses on trucks within 50 mi of you.

I'm glad you made sense of that because I was thinking wtf!

Your dad owns the shop and he charged you and you don't trust what they told you? LOL

haha sorry I meant my dad's mechanic shop. Yeah I have notice some coolant slowly leaving the coolant res. Is that a reasonable price? I noticed it didn't overheat on the trip there or back. I guess it's when I've been driving for a few hours in hot weather?

The freeze plugs are so if your engine cooling system freezes because of a bad coolant ratio and cold weather, they will pop out as the ice expands to reduce the chances of a cracked block. Although, they don't work very well IMO, the block usually gets cracked anyways if it freezes. The question is why is the plug leaking? I'm guessing corrosion.

That's what it sounds like to me too. But replacing the radiator may not be enough. If rust corroded that freeze plug, the plug may just be the beginning of it if. In fact, if it's not leaking enough out of the freeze plug to even make a puddle on the ground, is that what's really overheating his engine? OP, is it leaking on the ground?

This is a big question to the OP.. Do/did you ever have rust in the cooling system?

Haven't had any rust in the cooling system or leaking on the ground at all. Should I have them go ahead and do the plugs for $120 parts and labor?

If the freeze plug is leaking it needs to be fixed regardless, so yeah, I would go ahead and do it. Hopefully it will take care of the overheating. A loss of pressure can cause overheating like athlon450 said.

Not an expert but it sounds like you may have air in your system.
I had a similar issue a year. Got my truck for $4500 with 64k on her but it was sitting for 5.5 years on a storage lot with no maintenance. i didn't do much checking other than making sure the windows, 4x4, transmission, engine and the basics were working. I drove her home approx. 100 miles with NO problems until about 3weeks later she started overheating. checked the radiator fluid and it was brown lol. (rust, and a mixture of red and green coolant) So i got a new radiator, thermostat, new cap and some toyota red coolant.

First; make sure u drain the entire system including the heater core any air in the system can cause overheating or no heat from your heater ( i used lung power to make sure the system was clean and clear before i added the new coolant)

Second; after i hooked up all the lines and thermostat. i turned the heater on and on full blast (position the lever for the head and feet setting) then i started my truck; while its running i filled the radiator(1 gals of red coolant and 1gal of distilled water) and revved it until there were no more bubbles then topped it off.

The entire process took about 1hr including the installation of new radiator and thermostat and i did it by myself.
Truck running great after 2 years just need some new shocks/struts and ball joints. Thats gonna cost some $$$$