Dumb question, but have you tried a pressure test on the rad? Is it possible your cap is pooched (highly technical term) and not holding pressure?

 

replaced the rad cap last week, but it is not from toyota. If it over heats today I will have a friend pressure check it.

 

Tortis-- Where did the radiator come from?

 

O'rielly's. It was relaced about 18 months ago. The fins are all straight and clean. I am starting the water pump and lower hoses replacement now. It still got pretty warm on the highway this morning.

 

My 94 3.0 did the same thing. Radiator was plugged..new one fixed it. What were the results of your hwy test after the new clutch fan?

 

The highway test after the clutch fan install didn't help.

Replace the water pump today, and the lower rad. hoses, and in town, the temp gauge stayed at 1/4. Got on the highway, and the temp gauge went right to halfway, but I was able to drive 70mph instead of 60mph..

I am replacing the rad next. The rad and water pump are both under warranty, so no cost to me.

 

what is the normal temp for our trucks? I haven't noticed the temp much until mine overheated this weekend driving to phx. I replaced some leaking hoses behind the engine next to the firewall and that didn't help so I changed the tstat and that helped a little but even just driving around my lil town the gauge reads @ just below 1/2 until I start driving over 60mph, then it climbs a lil. My rad looks hella clogged so having that cleaned would be a good start i guess but I'm not sure about the water pump either. Mine also passed the pressure test but I dunno where to start.
We're in the same boat and it sucks

 

What mixture of coolant are you running? If you are running pure antifreeze the truck will run warm and may overheat it needs a mixture of 50/50. Did the thermostat you get have the jiggle valve in it?

 

22, I hate being on a sinking boat.

85, I am running about 60/40. The t-stat does have the jiggle thing. what is the jiggle thing for?

 

Unless you live in an extreme winter environment, 30% coolant is PLENTY for lubrication & general freezing protection. Water is a superior heat exchanger, so don't run any higher percentage of coolant than you need...

You can clip the jiggle thing off with a pair of cutters. It serves no useful purpose.

 

Put the new rad in this evening and I did notice a better flow at the rad cap.

the gauge ran a little cooler, but it is only 87 instead of 101 degrees outside.

 

I would drain some coolant out and try to get your mix to a least 50 percent water 70 would be better. As long as you have 30 percent antifreeze in there you are fine. The jiggle valve helps bleed the system. Some people break the jiggle valve off so that more coolant passes through it. I know from experience if you run a thermostat that wasnt built with a jiggle valve or hole when one is required it will sometimes run hot or overheat after a few minutes.

 

Well, It seems the radiator was bad after all, so far. I ran it on the highway and it stayed at 1/4 on the gauge. It is not hot here today, and tomorrow it is going to be 80 for the high, so it maybe Friday before I know for sure. The water pump had some worn out looking blades, but I can't figure out why they would have worn so badly in 18 months or so.

 

If water pump blades are wearing, it's one of two things; 1) the bearings are shot & they are hitting the pump housing or block, or 2) you have some type of abrasive in your coolant!

 

Any update on your overheating tortis? Im dealing with similar problems and following this thread helps me understand whats happening in the old 3.0 lava machine I am running right now.

 

I had overheating issues with 3 brand new thermostats. Finally read online where a Toyota owner suggested drilling a 1/16 hole in the center of the thermostat. I did just that and everything has been perfect ever since. Maybe this could help...

 

are getting pleanty of flow from your water pump? maybe that water pump you got WASNT WORTH THE MONEY YOU SPENT ON IT. you can always mount a pusher electrical fan on the other side of the radiator so u can flip the switxh to cool it down.
Also you might want to just take one of those IR tempsensor and shoot engine temp idle and after a short trip..

 

I had a slow coolant leak that I didn't notice for awhile, and unfortunately I may have run it pretty hot a few times with very little coolant in the system.

I got the leaked fixed, and it's full of coolant. I replaced the fan clutch because it was near shot. On slow highway drives the temp stays about normal, but when I begin to push it much at all, the temp starts to climb up over the middle mark. Sometimes it will climb all the way to just before the red mark. I can control it if I put the heater on.

There's a newer T-Stat in there, but is there a possibility I burned it up when I was low on coolant? This is the only other thing I can think of. Except I do have an aftermarket muffler installed, and the muffler shop did somewhat of a jenk job putting it on, could this have anything to do with the overheating?