My 2001 Tundra is overheating

I have a 2001 2WD Tundra with the 4.7L V8. It is not my daily driver and was gonna help someone move the other day (seems to be the only thing I use a truck for any more) and noticed my radiator had a very small leak (about 15 drops a minute). Deciding to address the situation I bought a new radiator and new hoses and new thermostat just to get it all. My water pump was replaced within the last 50k not sure when exactly.
When I fired it up to look for leaks unnoticed the truck starting to overheat. I then replaced the fan clutch also. I bled the system as best I can and I'm still overheating.
Has anyone else seen this before and if so what did you do to address it?!

 

Also does anyone know the temp range it should be running at?! I have a reader and I've been shutting the truck down around 230 where the temp needle starts to rapidly approach the Red H

 

Sounds like thermostat is stuck.

 

So in trouble shooting I cut the old thermostat so the metal ring and O ring keep it from leaking but it will not restrict fluid flow and I'm still having the eat issue.
Sitting at idle with the heater on it will maintain around 223 or so but when driving or revving it goes up and doesn't come back down till I shut down and let cool

 

And idling with heater off it just keeps climbing. It was approaching 240 (237) when I shut it down from idling and no heater

 

Thermostat or water pump failure. Mine runs at 195.

 

Belt routed the right way?

 

Definitely not the thermostat, Like I said I cut out the center of the old one so when i reinstalled it it is just an opening. Takes longer to warm up but it will not restrict liquid flow to the radiator.
My water pump isn't old, but it could be damaged. I didnt see any debris when i changed the radiator from the pump fins though. All I can think it could be is the water pump or a blown headgasket- getting combustion gases directly into the water jackets and causing it to over heat.
Does anyone know of a way to check if the water pump is pumping correctly?!

 

if it were the head gasket, you'd more than likely have other symptoms - either white smoke out of the exhaust, milkshake for engine oil or blowing hoses on the cooling system. Did you torque the water pump fasteners with a torque wrench? any chance debris got in the system during the rad change? Small pieces of discarded plastic film can really eff some s*** up...

 

when you run the engine - do all the coolant pipes get warm/hot? if they are all getting warm at roughly the same time - logic states that water is flowing around rather than heating up through conduction which would take longer and appear at different time in different hoses.

 

The upper hose gets hot, and the top of the radiator, but the lower hose is only hot near the thermostat housing. the closer on the hose toward the radiator the colder it gets. I have been trying to find out if that is the supply to radiator side or the return side. if it is the return side it makes sense being cold as it has already transferred to heat to the radiator. If it is the supply side then my pump is probably bad. does anyone know what the direction of coolant flow is on this truck?! also normal operating temp of the coolant system?

 

Does anyone know how to test if the pump has failed?

 

Squeeze the top radiator hose with the engine running you should feel a surge of pressure when released if not you either have pump failure or a blockage in the system.

 

Air pocket in the cooling system...or you have a bad water pump.

 

Why did you remove the thermostat? Now you have the same temp water thru out the system

 

The thermostat is designed to prevent coolant from entering the radiator until it reaches a specific temp (usually 180 F). This allows the engine oil to reach optimum operating temperature quicker and reduces wear on the engine. By installing the old thermostat with the center cut out I can eliminate a potential bad thermostat that isn't opening and therefore not letting coolant get to the radiator. the fact that I know there is no blockage from the thermostat, lets me know that isn't the problem. Now the question is is it a blockage, a bad pump, or potentially a bad head gasket (although I have no signs of a bad head gasket other than the temp).

 

I did that years ago when I blew the head gasket...it will buy you time But not much.

 

God I hope you are right!!! I dont have a lot of free time so I had a chance to get this far last weekend but I wont be able to take a look at it again for two more weekends. can anyone tell me what it looks like when you take the radiator cap off and run the engine... does the coolant pressure out the top consistently? im trying to figure out how to tell if the pressure is normal or low.

 

You should see the coolant circulating.

 

I know this is a late follow up, but I eventually found a blockage. The new lower radiator hose that I had bought has a piece of rubber stuck inside it restricting the flow. Looked like residual from the manufacturing process. Goes to show, always inspect your parts before you install them. I wasted a lot of money on unneccesary parts and coolant before I finally found the problem.
Over the last year I have had no issues with my truck (even though I still only drive 2-3 times a month!) besides the rear vent window latches broke last time I took the truck off-roading for a camping trip. Still haven't fixed them, need to find the time and cheap parts!

 

Thanks for posting the solution!

 

This may help with the window latch parts: https://www.tundras.com/threads/access-cab-window-latch-repair.26105/

https://www.ebay.com/itm/2x-Quality...ot-For-95-04-Tacoma-00-06-Tundra/273140191272

 

If you are getting overheating and you can't find a specific failure point, check for a build up of debris on the radiator behind the air conditioning evap unit, this area gets clogged a lot.

 

Thanks for the post. I have a 2001 4WD 4.7 Tundra. In the course of 3 years or so I changed thermostat, radiator, water pump, head gasket, fan clutch, did a flush, head checked for curvature and pressure at specialized shop. It is still overheating sporadically. I drove one day about 200 miles without overheating and while running air conditioner. In the winter I can get away driving with heater on. Will check hoses for obstruction.

 

You sure you clocked the jiggle valve on the t-stat at 11-1 o'clock during install? Refilled with heat on, and burped the system?

 

I will double check on t-stat. How do you burp the system? Is there a valve on the engine to let the air out?

 

@Eugene R Got a new OEM radiator cap?

I've had a bad cap give intermittent overheat like conditions when it looses seal for a bit.


Burping our system is just driving it and then letting it cool. Just make sure the reservoir is filled.