3.4 overheating

Absolutely!
I’m not surprised by anything
Everything I have tried, I thought would work. I’m even open to going back to a cheap single core radiator!!

 

Yeah I could tell the different possible fixes you were thinking by the questions you were asking. I don't know if you can have too excessive flow and overheat? Like the radiator couldn't remove enough heat due to coolant passing too quickly through? But then the thermostat should just stay open a lil longer to compensate right?
Yeah, new oem thermostat or that Gates or Stant heavy duty one that looks similarly constructed

 

I’ll give it a whirl along with a few checks of flow tomorrow
One more thing I just thought of, the bottom radiator hose was manufactured out of two radius hoses with a “stint “ in between. It is thin wall but could it present turbulence or other troubles?

 

Interesting, that's the one that leads to thermostat right? You know I wouldn't think it woukd, but the more I learn the more I realize I have very few absolutes man lol

 

Another thing to try and replace I guess!!

 

Thanks for your help!!

 

Lol removing that hose sucks because than you have to remove the coolant from radiator instead of just being able to use those hose pinching clamps. Removing just the therm you can pinch the lower hose off and save yourself a little time. If you can buy the hose when you get the thermostat, yeah why not do it. Especially since we're in this specific spot and it's questionable. Good call.

 

Might as well
I’ve only drained and refilled 100x already!
What once more!!

 

I would doubt it is causing the over heating but it may help you narrow down the issue if you don't have two things going on at the same time.

 

Gosh that's gotta be annoying as all get out by now. But I'm sure you've learned the tricks to do it nice and effectively

 

A pro at it now
Know anything about water wetter?

 

It was a good idea until we found that it negatively affected something in the cooling system. This was prolly 10-12 years ago in the Land Cruiser world. I can't remember what it was but it was disappointing because the water wetter was actually lowering our operating temperatures.
Some chemical or component in the water wetter was affecting.... A gasket maybe?Head gasket? Nah I don't think it was that. Shoot I really don't remember now. I haven't heard it mentioned much here

 

Reviews are mixed and it has no freezing protection properties
You have to run it with distilled water

 

Uhhhh I thought we ran it added to our coolant and we were seeing like 5-12 degrees lower with it. I must be thinking of something else if that stuff doesn't get run with the coolant mix

 

Reading further, can’t run it with 50/50

 

I'm chiming in with more of a question and sharing something I recently read. I saw somewhere the 3.4 5VZ should run at 198F under ideal conditions. I am NOT sure this is a fact, but IF it is true, what position would you then want the T-stat mounted? 6 or 12 o'clock? If you want to be around 198F, maybe it should be at 12 o'clock...? Or maybe somewhere in between, at a bit of an angle.

I had my T-stat replaced at 90k by the dealer when I had the timing belt and water pump done, along with a slew of other preventative maintenance. I do not know what orientation the tech installed the T-stat in and at that time I did not know to ask.

I can say that during the hottest part of the day in Sacramento CA in the summer, I have seen my engine get up to 206 on my scan gauge 2. The factory gauge in the dash is always dead in the middle.

 

One more thing: a step that sometimes gets missed is letting the engine cool after doing a coolant flush and topping the system off. Was that done? Are you certain the system is full to capacity and there are no air pockets anywhere?

I am running 60/40, with 60% distilled water and 40% factory red fluid. This was recommended by the dealer. Heat transfer happens with the water mostly. If you were to run 100% factory red coolant with no dilution, your engine would actually run hotter.

 

My factory gauge starts to climb at 206.
I’m replacing the thermostat today and not drilling holes in it.
Also checking for flow
I’m just above Sacramento in the foothills so I’m always driving in mountain conditions

 

The factory tacoma gauge is deadened to the center until about 220* or so before it even starts inching upward. Pegs on red at 260

 

You want the jiggle valve at the 6'oclock position...and normal temp for these trucks is closer to 190˚ at least in my experience. Mine is at 188˚ probably 75% of the time, might push closer to 198˚ if I'm wheeling or it's a really hot day out.

Only time I ever saw temps well over 200˚ was when I was still running e-fans that did a poor job of moving air.