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Two Stage Thermostat

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Old 02-15-2015, 12:23 AM
  #41  
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2-Stage (two-stage) Thermostat PN 90916-03070

Originally Posted by JKelly0117
I see the thread has moved onto finding better replacement studs, however I just figured I'd throw in my 2 cents. The two stage Toyota t-stat is the best t-stat I've had in the three Toyotas I've had. One being a 84 22r pickup, second being a 88 22-re pickup and third being a 87 22-re 4runner. Keeps the temp at 1/3 on all three rigs in both summer and winter. Worth every penny.
Tnx, JKelly0117, for steering discussion back to original topic.

Guys, I wanna replace mine with the dual-stage, too. Currently I have the drilled T-stat. No issues except that it takes longer than normal for the engine to get to normal operating temp. I believe that could sacrifice some MPG.
Does anyone know of a write-up on actual replacement procedure that mentions details/tricks we need to know not covered by FSM?

Last edited by RAD4Runner; 10-16-2016 at 01:23 PM.
Old 02-15-2015, 01:28 AM
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well a 22r is simple, however both my 22-re s I did during the rebuild
Old 02-15-2015, 07:49 AM
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I'm sure the details of the history of two stage stats involving Toyota and Mazda are very interesting. The purpose behind using two stage stats is different for both companies. The original Mazda two stage stat looks strikingly similar to the Toyota two stage stat. http://www.clubprotege.com/forum/sho...age-Thermostat It makes you wonder if they were both manufactured by the same company. Another interesting question is why did Mazda decide to change their two stage stat to a newer design. Toyota is using the two stage stat to address the design problem of a single engine, Mazda was interested in a bigger issue... using aluminum heads on iron blocks and extremely cold outside temperatures that produce thermal shock.

Last edited by chuckross1957; 02-15-2015 at 08:11 AM.
Old 02-15-2015, 09:44 AM
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Originally Posted by RAD4Runner
Does anyone know of a write-up on actual replacement procedure that mentions details/tricks we need to know not covered by FSM?
Have a heli-coil kit handy.
Run a thread chaser through the threads
Use anti seize on the bolts/maybe use liquid thread sealant with teflon like chuckross1957 has done

For the paranoid, use studs instead of the factory bolts and torque to factory specifications. 19 N-m or 14 ft-lbf
If you can't use a torque wrench use a 1/4 drive ratchet so you don't end up with too much torque helping to strip the threads.

.

Last edited by Odin; 02-15-2015 at 09:47 AM.
Old 10-16-2016, 02:00 PM
  #45  
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Received my two-stage thermostat fromLC Engineering today. T-Stat has 85/88 degrees C stamped on it and that converts to 185/190.4 F, which makes sense.

However, I'm wondering... Picture of Toyota factory part on 4crawler's site shows a Toyota package, while actual I got from LC Engineering has a Tama (made in Japan) package with Tama PN WW52EM-88A. Could this be that Tama really manufactures the part for Toyota, OR LC Engineering is selling less expensive alternative for the price of Toyota OEM?

From LC Engineering:
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Toyota Packaging Picture on 4Crawler's Site:
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Also got gasket. It wraps around the edge of the T-Stat like below. Do you remember yours looking like this?
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Originally Posted by chuckross1957
The original Mazda two stage stat looks strikingly similar to the Toyota two stage stat. http://www.clubprotege.com/forum/sho...age-Thermostat It makes you wonder if they were both manufactured by the same company.
chuckross1957,
Perhaps the above pic answers what you're wondering about?

Keywords for searches:
twostagethermostat, dualstagethermostat, 22recoolingsystem

Last edited by RAD4Runner; 11-21-2020 at 10:58 PM.
Old 10-16-2016, 04:53 PM
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I'm back to using the Stant 180 degree superstat. It seems to be a better choice for me in my climate and because I'm running such a large gap (.044) on my spark plugs. If I'm ever in a situation where I have frequent sub zero temperatures, I'll swap back to the two stage stat. I did find an interesting document linking the Tama part # to the Toyota part # ( it is in the cross reference section) and some Mazda p #s. http://www.nitomainc.com/npsp2.php?m...o=BP6F-15-171A

Last edited by chuckross1957; 10-16-2016 at 05:15 PM.
Old 10-18-2016, 09:08 PM
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Hey Ray,

As far as the Tama brand, I don't know if they are OEM for Toyota. I just went to their website and can only go by what it states which is the parts under their brand are made by OEM's. And yes, the gasket around the thermostat is needed and my Toyota cam with one.

http://www.tama-e.co.jp/en/business.html

I guess if you were going to look into using a Tama it may be worthwhile looking into an NTC one that is made for Mazda. A friend of mine who is into RX7's had told me that NTC was the OEM supplier for cooling parts. Just a quick search brought up this part no.8AK1151719U which I think cross references to the Tama part no. However, I don't know if it comes with the gasket or not. I don't know how much you paid, but if it's close to the Toyota branded cost, then I would just get a Toyota one. If it's like $20 cheaper then.....I would probably try it! I had no idea about the options when I purchased my Toyota one so I didn't go through that dillema. If the one I have ever goes bad I'm going to pop in one of the KIA ones I got for super cheap. ***CHECK THIS OUT RAY!****

http://www.ntcl.co.jp/en/

***CHECK THIS OUT RAY!**** I know it's just amazon, but the seller is Toyota and says it's a genuine Toyota part, and the picture shows NTC on top!

https://www.amazon.com/Toyota-90916-.../dp/B00OW39HFA


Last edited by Grego92; 10-18-2016 at 10:50 PM. Reason: Add Information
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