Lately, for about a month or so (maybe longer) my temp gauge has been really jumpy in my '95 4Runner 3.0. I first attempted to replace the thermostat with a 180 degree one from the dealership curious to know if the one I picked up from AutoZone was faulty. I ran the truck, and bleed the system, and I'm almost certain there is no air in the system.

I did a search earlier today and saw that people had suggested checking the connections on the Water Temp Sender and the Engine Coolant Temp Sender. All the connections look good and I didn't see anything unusual. Is there a way to test these sensors before I buy new sensors?

I've noticed that sometimes the coolant may be boiling when I get home after a drive as well, but I have no other issues and had the heads machined and replaced head gaskets and everything else late last year. All of this has just recently started.

TIA!

Andy

 

my guesses would be a stuck thermostat or bad sending units...if everything seems okay, then maybe its the guage itself

 

Download the FSM for your truck Here

It has in detail how to test resistance of the temp gauge sender, and how to check the actual gauge itself.

 

I already have downloaded the manual, but couldn't find anything in there in regards to testing the resistance or the gauge itself. Could you point me to the correct area? Maybe i'm missing something....

Andy

 

http://ncttora.com/fsm/1990-1995_4Rn...emci/eng3r.pdf

Page 6 is for the ECT, engine coolant temp sensor, not very familiar with the 3vze except for there is 2 sensors

I promise you its in the FSM lol just dig around

 

Well after using contact cleaner and cleaning both the connections on the back near the firewall on the 3.0, I was able to drive the truck today and put about 75 miles on it. The temp gauge performed as expected and didn't jump at all. Maybe the connections were dirty, or maybe something was just loose and not seated properly. I'll continue to monitor.

Thanks for all the help!

Andy

 

glad that fixed it, I was going to say, hope its not a HG!