RR95V64R

I just had new heads, head gaskets and timing kit put on my 95 4Runner after I blew a head gasket. Everything is back together and the motor sounds great but the engine wants to overheat still. I flushed, refilled and burped the cooling system and replaced the thermostat and radiator cap today. I’m not leaking/ losing coolant. Radiator fans seem to be working well… unsure of where to go from here.

Any thoughts appreciated

Kindly,
Ryan

RR95V64R

Another detail I forgot; on both occasions I drove it the needle climbed pretty close to red and then fell back to dead center once or twice before finally getting too close to red for comfort when I killed it.

2ToyGuy

Did you top and burp it after you replaced the tstat? Are the tstat and cap OEM? It should open fully at 195° F. Worst case, you can check it in a pot of water on the stove, and a thermometer that will read up to over 250° F.
Did you leave the temperature control full hot while burping it? Did you ensure the coolant was fully topped after you burped it?

FanS? Do you have OEM fan and clutch, or an after-market electric fan? Is the fan shroud installed and in good shape? If you have an OEM fan, does it make a "whooshing" sound for 30 seconds to 1 minute after start, and again when the temp climbs above about the 1/2 way mark?

Have you tried getting a thermometer, the kind that reads remotely, and pointed it at the thermostat housing to verify the gauge's reading?

Have you tried leaving the cap off the radiator, and once it warms up, seeing that you have good flow across the radiator? Beware, there will be some coolant overflow as it warms up. Does the bottom hose get warm, but not HOT?
Did you replace the radiator with a new one, OEM?

All I can think of, real quick...
Pat☺

RR95V64R

thanks for the thoughts- first block of ideas around thermostat are mostly yes regarding temps- tstat, coolant, burping etc. the radiator cap is not OEM. However- the second block of questions is mostly unknown- I haven’t really tested the fan or radiator. The fan blows is about as far as I’ve gotten. Radiator and fan are original to the truck.

2ToyGuy

Presuming the fan shroud is on the radiator correctly, and is complete, ie: it's got the little strip on the bottom (it matters), I would say right off, the fan clutch may well be shot. Just cause the fan is moving some air, it may not be moving enough air when the temp gets up a bit. If, when the temp gauge get to/above 1/2, the fan doesn't start making the "whoosh"ing sound, and really blasts air through the engine compartment, it's definitely bad.
Also, if the fan is relatively easy to stop with your finger before the engine warms up, but after the "start" period, and remains easy once the temp gets to/above 1/2, bad fan clutch. It's just a plastic fan, and won't hurt you to test the ease of stopping.

Over and above all that, you might want to open the radiator cap, when the engine is cold, and LOOK at the down tubes you can see. If they're clogged up, or restricted with scale, etc, you've got a bad radiator. If you have water sitting on top of the down tubes when the coolant is drained below te top of the tubes overall, they're clogged.
Some radiator shops will pull the tanks off and rod out the down tubes, but it costs enough that replacing the radiator entirely is a valid choice. A good, 3 core, all metal radiator is not all that costly, and well worth it. I've got one in my pickup that's lasted probably 25 or 30 years now.
Also, check to be sure the fins outside aren't bent over, blocking/restricting the air flow.

IF, once the temp gauge gets to/above 1/2, the top tank of the radiator, over on the driver's end, doesn't get HOT very rapidly, you may well have a bad water pump. If you happen to have the radiator cap off, you can look in and see how much flow you have. It can tell you a bad water pump pretty easily. If you have very much water coming out the weep hole right below the water pump's pulley, bad water pump.

Hope something in all this is useful...
Pat☺

millball

Sometimes on 3vz's it is impossible to fill them completely full of coolant, except by disconnecting the upper radiator hose from the radiator,

then turning the hose up near vertical on the water outlet and filling from there.

RR95V64R

Super helpful and I think the answer is likely in the radiator and or fan. Sadly I had to leave the truck for a few weeks while I travel but this will be my next order of business. Thank you very much for your insights and I’ll let you know what I find when I return.

Ryan

RR95V64R

Thanks for your reply. Id not heard this before. How do you know if it’s full or not if it looks full?

millball

If the block is actually full, the vertical hose will be full to overflowing, and after some time, some coolant will get by the closed thermostat and the coolant level in the radiator will rise.

RR95V64R

Thanks for all the thoughtful replies. It turned out to be a bad fan clutch. Rebuilt and she’s cool as a cucumber