It appears the thermostat is stuck closed (OE one lasted almost precisely 300k miles - try that with a Stant).

I am not home and wanted to repair it asap tomorrow am. There is a NAPA nearby which has the OEM TAMA thermostat and needed gaskets ($35 for the t-stat and 2 gaskets - good deal). Much, much cheaper and and lots closer than the Lexus or Toyota dealers in Bellevue. All I have with me is a 3/8” craftsman socket set I keep for emergencies, and some random wrenches at my friend’s house (no big tool set). I am thinking thats adequate to get at it given what I recall is that all I did to access that area in the past was remove the airbox and then the inlet pipe was right there and had 10mm bolt easily accessible.

Sound correct?

3/8 ratchet
10mm socket
12mm socket
6” 3/8 extention

Couple of bud lights on the engine cover. (Optional)

I got some cheap but tasty Sauv Blanc at Trader Joe’s tonight, I guess that will have to do. . There’s some Rainier in the fridge at home, but I’m not there.

Thanks! That’s what I thought and I have all that in my “basic” trunk tool kit. I have extra extensions, etc. to round out the kit so I can change a serp. belt, etc. with it.

I am forever reminded to chuckle when a Master Mechanic’s car is tripped up by such as this. Oro, I am among the many here that recognize the wisdom in your words, but... A 300K Thermostat? Really? C’mon, man... lol

Hope it goes well.

Ha ha. There’s a real story about why the t-stat was in 300k.
I took it out at about 225k to replace it preventatively. I had not at the time appreciated the significant difference in the quality between OE and aftermarket t-stats. I had a Stant or similar in hand when I had it all apart and then said “screw this.” I was not putting the new stant in to replace the (then) 12 year old OE t-stat that was working well. It would have taken two days to get a factory t-stat at the time, so I just put the OE back in and belayed the job to the next t-belt interval or such.

I didnt’ make it quite that far, but it’s a small job and I don’t regret putting in a cheap aftermarket part than can fail catastrophically. I’m totally a bargain hunter in general, but t-stats are not a place to do that!

So as an FYI for people, NAPA has an OE quality t-stat available and generally stocked at their stores, for $29.

The listing says it is made by TAMA and they are OEM. Compared to me OE thermostat, it is as robustly built, with only tiny design differences. The gasket for the perimeter of the tstat was $2.5 (it was $12 at the Toytota dealer, I called to check).

So it’s good to be able to go grab quality parts elsewhere.

Definitely not around here. It was $42, plus the gasket. And $37 at the Toyota dealer (plus the $12 for the $2 gasket, making it effectively $50). I didn’t ask the lexus price for the gasket, but would imagine it was then closer to $60 at the local dealer vs. $31 at Napa for the exact same thing.

$20 and change for OEM stat and gasket online.

But when you’re stuck somewhere looking at a dead 300K stat, a good STANT in hand is truly priceless. Let him gloat.

Correct - my point was that when you need it TODAY, you can go to any Napa and get a fair deal for real OE parts. I wanted to pass that on so the forum would know and be able to take advantage of it if the need arises for them, or pass it along to a new poster who urgently asks about a thermostat problem. (Not intending to gloat. ).

I replaced the radiator last summer and upgraded it to the 1” (it was the 5/8” model originally). I SHOULD have thought to replace the t-stat then when I could have ordered ahead, and saved also the extra gallon of coolant that was wasted on this failure. I don’t know why I did not think to do so since I knew this was an issue (original thermostat still in it).