Well, I'm going to go right now and take out the rad to see what it looks like inside. Hopefully either cleaning it out really good, and checking the water pump will take care of this problem. I really don't want to get into the heads..

There is a little history. A friend of mine bought it because the hg's were gone - it was over heating. He's a licensed mechanic, he replaced the gaskets and put it all back together. He swears he did not mix up the gaskets, he's not a liar, and is a fiarly good mechanic so i am inclined to believe him. However, after he put it all back together it began overheating again, so he replaced the t-stat. Drove it for two weeks and had no problems what so ever. Then he parked it, and there it sat over our 6 month intensely cold winter. In the spring (this past March) I bought the truck and the overheating started for me. Thus, I took out the t-stat, drove it for nearly 2 months without issue, and just yesterday I replaced the t-stat and it all started again.

So, from what you all have said I am going to take out the rad, inspect the insides, flush it and see if anything comes out. I'll also replace the water pump as I have one spare, and hopefully this will work. I'll let you know when I find out any more.
Cheers.

 

After you drain it and when you pull it out if it is really heavy for its size then its mostlikely clogged.

You could possibly get yours recored. Its cheaper than buying a new one.

 

Now that I see you're in very cold weather, that would probably be a good idea. If the t-stat doesn't have a jiggle valve, I'd say drill a couple of 1/8" holes, one at 12:00 and one at 6:00.

 

alrighty, took the rad out, reversed flushed it, and nothing came out. It looks a little dirty, but it does not seem clogged inside.

Next step is to take the water pump off and replace. I will drill holes in the T-Stat, but I am wondering if this is required, as should the T-Stat work w/o having to have holes in it?

 

Yes the T-stat will work without drilling holes in it. I was told it is just to help "burp" it. I think the effects of the two little holes, even if the T-stat stuck closed would do very little.

About how heavey was the radiator? My old one, was pretty darn heavy compared to my new one, and it was caked (almost looked like calcium deposits or something like that.)

 

Well the OEM t-stats come with a hole (jiggle valve) already, but I'm guessing you have an aftermarket t-stat without the hole right? Isn't that why YOU brought up the idea in the first place. There are 2 schools of thought on placing the jiggle valve, one says put it at 12:00 so the air can escape more completely, the other says put it at 6:00 so you can drain the coolant more completely without pulling the t-stat. By drilling 2 holes (top and bottom) you get the benefits of both ways.

My other reason for saying it may be a good idea is in case the t-stat is closing on you while driving in very cold temps. It might just be enongh flow to help keep the t-stat from cycling open/shut. No normally this is not a problem with the 3.0 but something may be wrong with the coolant flow with your engine (like maybe the oil cooler is clogged up). Normally the oil cooler return line dumps out right on top of the t-stat and helps keep the t-stat open.

The t-stat cycling is a problem with the 22re in cold weather and Toyota makes a dual t-stat for that engine. Drilling the holes helps keep the t-stat from closing much like a dual stage t-stat works.

In any case the holes won't hurt anything and they won't cost you anything as long as you already have a drill.
Good luck

 

DOH! Should've just tried the frickin holes before I ripped apart the front end of the engine. Oh well, not that I'm here I might as well replace the water pump - although I've not put the timing out yet, I could just drill the holes in the t-stat and put it all back together.

In regards to the weight of the rad, I would say it's about 15-20lbs.

I don't know how the problem could be the water pump, it's driven by the timing belt as mentioned above, and it's pretty simple in construction...I think even if I were to replace the water pump it would not fix the problem - I think it's the rad.

 

Problem appears to be solved...
I took the thermostat out and drilled two 1/8" holes, top and bottom (12 and 6 o'clock). The truck drove for approximately 30 minutes without overheating which it would not do before.
My only question is, with the two 1/8" holes will the truck still run at normal operating temperature during the warmer months?

 

Great, yeah it might run slightly cooler in warmer months because of the extra flow. Nothing to worry about, keep in mind at normal temps and conditions the t-stat is open (big hole ) anyway.

 

Even though you fixed your problem I'd also recommend checking your fan clutch, considering your temperature fluctuates with your rpm and speed, it also may sound like your fan clutch is bad. When the engine is cold push the fan and make sure it moves only slightly, like less than a quarter of a turn. If it continuously moves then its bad.