348 thermostat and 140624 alternative

My thermostat failed open (bottom bracket broke allowing spring to force open). The OEM thermostat is ridiculously expensive and based on my research fails as-new more than any part has a right to.

I measured the bypass port at 25mm (see image) with room up to 42mm, and flange to port at 42mm (measurements approximate). This means any 56mm flange thermostat with a bypass plug of >25mm and <42mm that will open >42 mm (flange to bypass) will work. Pick your temp.

I found Gates 33798 (2006 Prius)
Advance/Carquest 14108
56mm flange
35mm depth to bypass flange
28mm Bypass flange
180F

I bought the Carquest 14108 which is a MotoRad (see image); $10 and measures the same, not sure of it’s manufacturer part no.

OEM Toyota maybe worth your time too; not sure of manufacturer.

As part of the project I also sourced a replacement for coolant hose 140624, which is also ridiculously expensive. Took some measurements, and searched local parts retailers and found Gates 20470 has a bend with the exact angle needed. It’s $10. Requires trimming to fit, but works perfectly (see image).

Both parts work as they should, will save you $200 +/- and I’m betting the thermostat will be more reliable.


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A few message threads with some considerations when choosing an aftermarket thermostat...

https://www.ferrarichat.com/forum/threads/348-thermostat.490525/

https://www.ferrarichat.com/forum/threads/348-355-thermostat.496181/

https://www.ferrarichat.com/forum/threads/thermostat-question-348.395227/

Bleed hole required?

http://www.birdman308.com/service/thermostat/thermostat.htm

 

The MotoRad thermostat I referenced above has a bleed hole. Should have noted that.

The previous threads I found focus on matching up exact dimensions of the OEM thermostat, but that is not necessary. It just needs to operate correctly in the housing at the right temp. The thermostats in the previous threads that reportedly work are only available overseas and with shipping run $50-100. The others have a smaller flange which Birdman and Ernie both notes cause issues.