How old is your rad? How clean is it when you look in the top?

It’s easy to tell when the stat is open and coolant is flowing through the rad with the cap off. It will flow by the cap opening really well if you leave enough of an air pocket. Something you’ll never see with that “burp” funnel sticking in the hole…..

When I fill a cooling system I fill until I have a 1” gap under the cap and start the engine, and leave the cooling fan off. Just the heat lever on max temp.

As the air pushes out I keep adding coolant until it stops dropping. As the engine warms up and the coolant expands….when the level hits the top of the rad I’ll put the cap on.

When you say “turn them off” are you turning off the fan and putting the temp lever to cold or just turning off the fan?


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Radiator and cap are ~2 years old. It looks very clean. I've filled and drained my coolant a few times since the head gaskets and it comes out basically the same clean pink color every time

Yep!

Ok, so that sounds like either my t stat isn't opening, there's a blockage, or the water pump isn't pumping.

The tstat seemed to operate correctly when I boiled it (see video). Also, it was working just fine before the head gasket work, so idk how it would go bad just sitting on the bench. I'll try a new one anyway just to be double triple extra sure.

The water pump is a brand new aisin unit being driven by a new timing belt which is being tensioned by a new tensioner.

As far as a blockage, is there any way to test for that? It stayed cold (~145-155°, max 167° up a long steep climb) without a thermostat so it seems like there isn't a blockage, unless it's only partially blocked and would have actually been even colder.

Leave your temp setting on max heat. That shuts off the external coolant loop.

Leave it on max heat.


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Head gaskets could be on backwards blocking flow.

One of the gaskets could be leaking depending on surface prep.


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Might try a new thermostat.

Radiator, Radiator Cap, Thermostat, Water Pump, Timing Belt, Timing Belt Tensioner all new or nearly new.

Thermostat removed and tested anyway just to make sure... it works fine (vid).

Coolant coming out is the same color as the coolant that goes in.

Air in the system has been thoroughly bled/burped multiple times.

I'm still gonna try another thermostat even tho mine tested well. I already have the new one in hand and I boiled it and it performed almost identically so I don't see any reason why it would work.

I think it's time to start considering...

These other 2 threads I found describe my exact symptoms as well. So it may be time for me to start digging in again

Help! Overheating issues after new head gasket, can't figure it out


(toyotanation.com) 97 Overheating..Help

By the way, another observation I had:
sometimes my dash temp gauge begins moving well past halfway to redline when my computer still saying 185 degrees. If i leave it alone the gauge will continue on to red and my computer will read 210+ but what I believe this is confirming is that the coolant is not circulating and even with the thermostat out it will probably suffer from hotspots.

Confirmed, Head Gaskets are on wrong heads.

This is a DRIVER-SIDE gasket i got from yotashop.com. On one corner it has L marked on it.


And here is a picture of my PASSENGER-SIDE head viewed from the wheel well with the splash guard taken down

Glad you figured out your problem.

You get the gold star for guessing the issue first!

-Charlie

Even a blind squirrel finds a nut once in awhile!

Did you replace the head bolts when you replaced the head gaskets?

If you did will you replace them again since they may be considered

stretched after torquing and some heat cycles.

The head bolts are not torque to yield.
The FSM says "If any bolt is broken or deformed, replace it."
and if while torquing them "If any of the cylinder head bolts does not meet the torque specification, replace the cylinder head bolt."

Finished re-doing the head gaskets.


Went on a couple test drives.
Coolant temp steady @ ~180-190° with 170° thermostat on my twisty mountain roads

Thanks everyone for the help!

Awesome, glad you got it sorted!