Coolant Temp/Sensors
 

Hi all, I've been a lurker on YT for more than 15 years since I bought my first t4r and have saved tons of cash by searching and reading all of the amazing posts on here, so THANK YOU! That being said, I've got a problem I can't seem to find a definitive answer to. I have a 94 Pickup with the 3.0 v6, manual trans, 4x4 and AC. I had the head gaskets replaced at 95k miles along with a new thermostat and water pump. The truck now has 123k. In the last few weeks I've noticed that it seems to take a while for the temp gauge to start moving, then it (quickly) moves up to the mid point. It then seems to fluctuate between the midpoint and 3/4 or so, which it never did before. It also seems to be taking an extended period of time (7-10) minutes for the air coming through the vents to get warm. From what I've read, this doesn't seem to be an ECT sensor issue, or is it? Kind of stumped here, any help would be greatly appreciated!

Side note- the truck is running as it should, no loss of power or mpg.

It's hard to fairly compare how the heat performs between fair weather and cold weather. But assuming your observations are correct, I would suspect a sticky thermostat. It's stuck open (slowing your warm-up), then quickly closes (spiking your gauge), and then works intermittently (causing the gauge to fluctuate.)

You can test a thermostat http://web.archive.org/web/201311071...10thermost.pdf , but for the price of a replacement ($4-$14 at RockAuto) I would probably just swap it out.

Also check to make sure since the 30k of added mileage your coolant levels are still within minimal range and if not, then check for possible leaks.

Thanks for the input! Took it to the local Toyota guy today to replace the AC compressor. He said there was some leaking around the thermostat housing. I'm assuming that may lead to the issue. Will find out more and update. Thanks again!