How-to Thermostat Toyota 3.3-liter V6 3mz-fe 3.0-liter 1MZ-FE - Sienna Camry Highlander RX330 RX300

For Toyota 3.3-liter V6 3MZ-F and 3.0 liter V6 1MZ-FE. Basically the same engine with some minore differences. The inlet tube to the thermostat housing is slightly different between the two engines but the fasteners for the housing and its position are the same. The thermostat is difficult to access on these engines. How to diagnose a bad thermostat. How to verify a bad thermostat. How to remove and replace the thermostat. How to pressure-test the coolant system. Vehicles with these engines are Toyota Camry, Highlander, Sienna, and Lexus RX300, RX330.

[@Adam-kb2mn]

About to do mine.Good to see whats involved

[@Merryfrankster_]

Thank you for watching and for commenting.

[@antrinh5525]

3mezfe is a 3.3 liter engine, the 1mzfe is a 3.0 liter engine. they are almost the same with the 3mze is slightly bigger at 3.3 liter vs 3.0 liter. the 1mze has a sludging problem due to the faulty valve cover, if switching to the 3mze valve cover it will eliminate the problem.

[@Merryfrankster_]

Unfortunately, 20 years down the road, it's too late for a new valve cover. The sludge damage is done. A new valve cover does not reverse it.

[@gman4141007]

Fuck, i have the 1mz, wish i knew this earlier 😭

[@winder6]

Great job, Frank. That cooling system pressure checker, could it be another way for checking for blown head gasket? Great video cheers

[@Merryfrankster_]

The pressure tester could be a way to check for head gasket leakage but if the water is leaking into the cylinder or into an oil galley you are not gonna see it. Tough to say. To diagnose anything, it is preferable to take complementary but independent data points, each one alone might not be sufficient, but in combination they give a conclusion with high confidence. Example with this thermostat. Overheat, cold radiator hose, plus boiling water test. What if the thermostat had passed the boiling water test? Well then, we would have to gather more data. In some circles, this is called the scientific method.

[@winder6]

@Merryfrankster very good, thanks 😊

[@gman4141007]

Thanks for this video, i have the 1mz and had the same symptoms with half the radiator being cold, the car never overheated so i dont know how it can be a faulty head gasket with only 93k miles

[@Merryfrankster_]

This indicates a blockage or the thermostat not opening.