omuddr

'97 4Runner - V6

Replaced the head gaskets after the original failed and started leaking coolant into the number 2 cylinder. All hoses, gaskets and water pump replaced. It appears that there is no flow of warmed coolant pass the thermostat. Checked the radiator and it has good flow. Thermostat checks out okay. Removed the thermostat and refilled... get good flow back to the radiator. Any thought's on what to try next? I'm thinking about removing the bypass hose from the water pump to see if coolant is flowing from the oil cooler out the side of the block. Vehicle runs perfect except for the overheating issue. In addition, when I open the heater valve wide open the truck runs in the normal range. I guess it's acting as my radiator at this point.

mt_goat

So the truck runs cool or normal with no t-stat in place? But it over-heats with a working t-stat in place?

omuddr

To be honest, I didn't run it long enough to determine if it stay cool with the thermostat removed. I will perform a more thorough test this evening. Definetly runs hot with a good thermostat installed. The key is that the warmed coolant never circulates past the thermostat, so in turn it does not open.

MSR

sorry to say but you put the head gaskets on wrong sounds like the right is on the left. seen other shops do the same thing

GSGALLANT

Crap... you beat me to it MSR! That's what it sounds like to me too. Did you take any pics during your HG installation that you can post up so we can have a look?

mt_goat

Was that possible with the 5VZFE too? I know it was common for it to happen with the 3VZE.

GSGALLANT

That's the part I'm not sure about. I've replaced the ones on the '93 I used to have (and it is possible to install them incorrectly on the 3.0L, and still have it run fine except for the overheating - although I did install them correctly)... but I've never removed the heads on my 2002. One would think Toyota would have tried to correct that... given how many screw ups there were when installing head gaskets on the earlier engines, but who knows? I do know that in my FSM for my 2002, in the section for installing the heads, there is a note that says "Be careful of the installation direction" right after the step to place new HG's on the block... that would lead me to believe that they can be mistakenly interchanged.

If omuddr took pictures during his install (which you should always do, by the way), it would allow us to verify that they are installed correctly and at least rule that out as a possibility.

MSR

yes the same is possible on the 3.4 you have to watch the coolant passage on the driver side head that drains right down on the thermostat. also the lettering on the 3.4 gaskets face down not up like the 3.0

97ltd4x4

Sure sounds like the headgaskets are upside down as well blocking the block/head passages...I have seen this happen in the shop a few times...

mt_goat

Bummer, who did the job for you? Take it back.