Have a 97 4runner 3.4L over heats only when driving, takes about 5 min factory gauge will peg in the red. Installed mechanical gauge it will read about 240 checked with external temp probe, it shows 215 at the top radiator hose housing (gooseneck on intake). Has 212000 miles. Things done, new bearing, rings, water pump oil pump, new gaskets on everything heads have been machines, new temp switchand temp sensor, new crank sensor, radiator has been rodded and cleaned, new Toyota thermostat. Any ideas would greatly help I am at a loss

 

Head gaskets installed upside down? Post 54, 56.
https://www.yotatech.com/forums/f2/9...tumped-245391/

Did you use Toyota OEM HG?

What was the temperature before the engine work?

 

Head gaskets on right, don't remember what the temp was, isat for 4 years before rebuild. It did blow a head gasket that was the reason for rebuild. Not OEM HG

 

Is the thermostat opening at the proper temp?
Cooling system is totally burped of air?
Fan clutch is working?

Did you have the heads pressure tested?

 

Fan clutch is working it was checked recently.
System as far as I can tell is burned but not 100% sure.
One head was replaced. Plugged oil passage it is good the other head, not sure if it was pressure check when I had it at machine shop. Have not checked the thermostat to ensure it is opening. I do know.that the radiator.is hot on the top half and goes from warm to almost cold as you move towards the bottom. Bottom rad hose is slightly warm when it shows it is over heating.

 

Something is seriously blocking the coolant flow or exhaust gases are still getting into the coolant and heating it up. Was a rag left behind in a outlet or hose in the cooling someplace?

You might pick up a Block-Check kit to see if exhaust gases are in the coolant.

 

Maybe a mod can move this thread to the proper forum also.

 

Sorry new to the forum didn't know where to post. Gonna do some more checking tomorrow. Thames for the help so far and sorry if I posted in the wrong area....I'm just a newbie...lol

 

When you filled the radiator did you leave a heater hose unconnected to allow the air to burp out? More than likely you have no coolant in the block and just the radiator. I've seen that happen many times. I'll also remove the upper hose from the radiator and fill into the upper hose so it fills the block first.