Theyseemespoolin

I just installed a new mechanical coolant temp sensor/gauge after getting fed up with the cluster gauge. I have flushed my radiator, checked all the lines, etc. The previous owner looks to have replaced water pump, and most likely thermostat. The temp gauge will read sub-150 for a long time, then climbs steadily to 210, 220, 230+ farenheit. When it passes 220, I slow down, ease of the throttle, and after 10-15 seconds, it comes down to 180F and stays. Haven't taken the truck on the interstate since putting in the gauge and flushing the rad.

Is this a normal temp cycle for the water pump/thermostat? I feel like going over 210/220 is a bit high, but I don't really know. I'm currently waiting on my account to be approved on the 22rte forum, so they might have different expertise.

Melrose 4r

Why risk overheating with an unknown thermostat? The first thing i do with every used Toyota i buy is pitch the thermostat and put in a new one of the correct rating. In my experience thermostats last about 120k miles or 10 years. After that you are on borrowed time. I believe the correct rating for the 22rte is 195* stat. Get a new one and then report back.

Theyseemespoolin

Aisin THT-002 is listed as OEM, but has a temp of 190f. Should I Amazon that b****?

87-4runner

Stock CT20 and exhaust?

Theyseemespoolin

As far as I know, stock ct20. PO straight piped it though.

87-4runner

I'm upgraded to a CT26 10 lbs boost...
82 Supra AFM
Custom charge tube, custom 2 1/2"
Down pipe and 2 1/2" all the way back...
oem turbo thermostat....
New head gasket ARP studs...
New fuel pressure regulator & fuel filter
Stock injectors
Stock ECU
no innercooler yet...

I run about 185 till the outside temps get to about 80 and running the A/C...
It will sometimes creep up to 210...
I can stay out of the turbo and yeh temps come back down to about 195-210

87-4runner

87-4runner

Theyseemespoolin

Beautiful truck 87-4runner. I think my thermostat is sticky but not stuck yet, just judging by the fact that it gets sooo hot before coming down. Definitely gonna get a new thermostat.

I've been reading about people drilling their tstats to make it "dual stage," where do you drill the holes?

arlindsay1992

iTrader: (8)

I've never heard of drilling the thermostat to make it dual stage. I've heard of and bought a dual stage thermostat. Cures the temperature gauge overshoot. See link at the bottom of this post. On other cars, I've also drilled a 1/16" hole somewhere on the thermostat flange to help burp the cooling system after installing a new thermostat. Many thermostats come with a small jiggle valve for this purpose. This allows air to flow through the thermostat so that the thermostat can be submerged in water. If there is an air bubble caught behind the thermostat it will not see actual coolant temperature and will not open. This makes is very hard to get the coolant to flow though the whole system and bump the air out.

https://www.4crawler.com/4x4/CheapTr...tml#Thermostat

Theyseemespoolin

From 4crawler link:

"A lower-cost version of this can be done by drilling one or more small holes around the edge of the single state t-stat to allow some coolant to flow all the time. This functions like the normal bypass hose on other engine designs."

So I guess it doesn't make the thermostat dual stage, per se, but it does provide a constant pathway for coolant to bypass a stuck/failed thermostat.

arlindsay1992

iTrader: (8)

A couple small holes aren't going to do anything for a stuck thermostat. They are there to allow easier burping and a tiny bit of flow. This is a band aid for the temp. gauge overshoot, which was a known issue by Toyota. The fix is the dual stage thermostat.

87-4runner

The OEM one has the dual hole