3VZE takes a while to get up to temperature

[Steven94]

I talked about this a little when I first joined here, but I have learned a few things since then that may give you guys a better clue.

So here is the deal. My 3VZE (automatic trans version) takes a while for it to read that it is up to temp. Most of you know that until it is a temp, it will not shift into overdrive. So I will be driving down the road at 45MPH in 3rd and at around 3,000 RPMs. I had the coolant temp sensor replaced a while back. The one we pulled out was so dry and corroded my friend was able to break it in half with two fingers. So we figure the coolant is not properly flowing to the sensor.

Any opinions on what is causing this?

Thanks,
Steven

 

[Footofgod]

Many new thermostats fail in the open position. If you have one like that and it has failed, it can cause the engine to take longer to heat up.

 

[Steven94]

I had considered the thermostat as well and replaced it a couple months ago. It didn't help.

 

[dubs283]

So we figure the coolant is not properly flowing to the sensor.

have you verified there is no coolant flowing to the sensor, or are you guessing there is no coolant there??

the temp guage sender in the engine needs coolant flowing over it to read properly, it will not read air, i.e. if the guage reads a temp, the sender probably has coolant flowing over it

have you tested the guage??

 

[Steven94]

I haven't looked recently, but we think that is what is going on. When we pulled the old one out it looked like it had not been wet in a long time. The last time we checked the temp sensor there was coolant on it, but we had just turned the heater on. When I turn the heat on after driving for a min., the gauge will jump from registering a quarter to half way (where it should be) in a couple seconds.

I have not tested the gauge.

 

[Steven94]

Have any of you bought a thermostat that didn't work from the get go? I really don't think this is the problem, however I won't rule it out completely.

How do you test the gauge? I am pretty sure my diagnoses plug is fried, so that probably wont work.

 

[Steven94]

Did another google search and found this answer. It sounds like this could be the problem.

"This answer comes from personal experience with exactly the same problem. It had the Toyota mechanics stumped for a couple years.

A water passage is probably blocked. There is a cross-over water passage, that has the coolant temp sensors mounted in it. This passage is in a reomvable casting, mounted on top of the engine, next to the firewall. It is not easy to get to. You will see it in the repair manual, when you look for the coolant temp sensors.

This passage gets plugged with crystalized coolant deposits, and sharply restricts coolant flow. It also traps air, the cause of the crystalized coolant. Note - The red Toyota coolant is what crystalizes, the green stuff does not have this problem.

You may want to purchase a new casting and gaskets, as the original may be eroded to badly to repair. If you dont get e new casting, at least get new gaskets. Remove the casting, and scrape out the deposits. Replace the casting and gasket.

Check the sensors for proper function before re-installing, or replace them with new ones.

Bleed as much air as possible, any way you can, from the coolant system. Air gets trapped in the casting, and does not conduct heat to the sensors. Design error on Toyota's part."

 

[77'911]

If your sure it is not the t-stat, you might consider checking the fan clutch. Replaced both the t-stat and fan clutch on our 1990 and made a big improvement (old f-clutch was eating power and t-stat was keeping warm up cycle on). You might also consider looking at your o2 sensor (might be running too rich).
regards