Workman

Rice18, your problem sounds like a problem with a connection or chaffed/broken wire. From what I remember, ( I hate electronics) the temp sender reads resistance which registers back at the guage. I would probably start by cleaning the connection to the temp sender and possibly the plugs at the back of the instrument cluster. Someone else may have some better ideas but that's where I would start.

As for my problem, I was able to find a few threads about the "U" shaped hose behind the plenum being a sort of trap for junk in the cooling system. Some recommended pulling the hose and shooting some compressed air into the hose with the t-stat removed. If I get off work early enough tomorrow, I may try this and report back. It's been showing warmer on the guage but still not enough to get OD, so maybe the whatever's plugged up is starting to work itself loose.

abecedarian

Something else might be the lower radiator hose is sucking closed. If that happens, nothing's going to circulate through the radiator but you will get flow through the heater since it bypasses the radiator. When things start getting hot, steam may build up beneath the thermostat... but it should still read hot though so ....
Hope you didn't blow a head gasket.

Anyhow, sometimes I'll pull the t-stat housing and stat out and fill the block up from there then re-install so that the only air is in the upper hose.

Workman

Problem Fixed! Only took about a month. I pulled the t-stat and the "u" hose and blew air in both directions. Sure enough, small chunks of silicone start coming out the t-stat opening. Put everything back together and filled up and the guage climbed to halfway in about 5 minutes. Project for tomorrow, if weather permits, pulling the heater hoses and cleaning or replacing them. The moral of the story, don't overdo the silicone with these engines. The previous owner must have loved the stuff.

Rice18

today to ensure a solid connection with the temp sender i spliced back the wiring got a new connecter and soldered the wire to the connector, a while back i had already tried to replace the sender, and we can now rule out the sender connection, i have pulled the plugs on the insturment cluster and it also had no effect.... for some reason i suspect an air pocket but it does seem highly unlikely that it would effect my gauge.

Workman

You may try the same thing that fixed mine. Pull off one end of the hose at the back of the plenum and blow some air through with the thermostat removed. Then bleed it. I found a redneck way of making a funnel bleeder like I used. Get a 2 liter soda bottle and cut the bottom off and cut a hole in the center of the cap. Wrap a little tape around the cap to get a good sealed fit in the radiator. You may have to plug the hose to the overflow tank. But fill the bottle and run the engine until air bubbles stop working their way up into the bottle. I've found that with this method, you don't even have to raise the front of the vehicle.

Rice18

thanks workman, ill give it a shot when i have some extra time, while im down there working on it should i go ahead and get a factory toyota thermo? or is it really going to matter at all?

Master_Yota

i went thru 2 faulty new thermostats on my 22re and the 3rd one was the good one. so just get different thermostat like a 195 degree.

Workman

It wouldn't hurt to get the yota thermostat. Mine was only about $15 so it's definetly worth doing while you're there.

Rice18

today, still hearing a horrible rushing sound in the center of my dash i decided to try to bleed the radiator more, i made a shotty funnel and went to warming up/reving the engine i began to get very large amount of bubbles out, i did this for around 25-30 minutes and had to stop due to my funnel warping under the heat of the coolant.... soo i havent completely ruled out air in the system.... how likely is this air going to prevent my gauge from working?