Makes sense to me. I agree the thermostat is very cheap anyway. I think my plan of attack is
- replace the thermostat
- bleed the cooling system
- if necessary flush the coolant.
I think we have a winner. I did replace the thermostat and it was stuck. I also ran the engine afterwards ad it read overheating at idle within like 3-5 minutes. However, nothing was hot on the car. The intake manifold wasnât hot, none of the rad components were hot. The valve covers were warm but that was it. iâm thinking a sensor is playing shenanigans. I disconnected the two wire sensor (twin turbo identifies as gauge sender in post 37 pic 1). the fans turned on immediately (yay working fan) but the gauge activity remained the same, it steadily climbed. not sure how if thatâs the gauge sensor. So Iâm going to reasonably assume the carâs not actually overheating. I am going to bleed the coolant system since i opened the system anyway to change the thermostat. Should I assume the coolant sensor mentioned before in that pic needs replaced? or do i have some kind of wiring issue if itâs climving regardless of whether itâs connected or not? But the fans do kick on if itâs disconnected.
Replace ALL coolant temperature sensors . . . theyâre cheap enough, and hopefully your problem(s) will disappear
I appreciate the response and i mean no disrespect but Iâd like to properly diagnose the problem to the best of my ability. I donât want to throw more money at this than is necessary. I know the sensors arenât super pricey but Iâm also working on an engine swap on my GFâs subie thatâs eating my finances.
The sensor next to the thermostat with one black wire and one yellow wire is the coolant temp sensor for the computer. Iâm pretty sure thereâs a seperate sensor for the gauge.
That would make a lot of sense. that would explain why the gauge made no change when i disconnected the sensor near the thermostat but it kicked the fans. on. I just need to find the other sensor. There is that other âfan switchâ in the second pic on post 37. the one green wire sensor. unless thereâs a 3rd coolant sensor.
Not sure. Might check out a website like rock auto and see what they list.
This site mentions that one wire sensor might be it. I did replace that before but mightâve been an improper part since the people at oreilly didnât seem to understand that well.
https://www.thirdgen.org/forums/cooling/528733-temp-gauge-not-working.html
I think the single green wire is for the gauge. You could unplug that bad boy and see what the gauge does.
Yeah, theyâre labeled incorrectly in the post with the pics. The one with two wires, Iâm positive, is the engine management coolant temp sensor. The green single wire, Iâm pretty sure, is for the gauge.
Yeah I can definitely verify through multiple sources that single wire sender is for the gauge cluster. the question is, is the sensor bad or is it a wiring problem. I guess If I unplug it and the gauge spikes then itâs definitely a sensor, if it doesnât then some wiring goof. Iâd assume since it slowly climbs not jumping or anything then itâs probably the sensor anyway but Iâll find that out tomorrow.
Yep, sounds like a plan. Unplug it and see if gauge spikes. I have no idea how to test it, so might just get a new one if theyâre cheap.
You are 100% correct, my mistake, I have a question if I may; I just had my water pump replaced and I still have an error message âlow coolantâ, is this a bad ECTS? I also would
tell you when we hook to my ECU we no longer get fault codes when we clearly have âfaultsâ, last month my BFF scanned and got 2 failed O2 sensors, one up and one downstream, now no fault codes at all, even with the âlow coolantâ error on the dash. The ECU cant be completely failed or my car wouldnt even run, any ideas? Thanks John
Well I ran into a new probably unrelated problem (go figure) the car is now stalling after a short drive. It will idle pretty much fine bt it seems after driving for a short bit, trying to accelerate causes a bit of problems. Iâm going to assume either fuel delivery problem ( looking at the fuel filter for starters) or a vacuum leak somewhere (entirely possible since I took the intake hose off to get to the thermostat something may be loose.)
ok stalling issue potentially fixed. when i messed with the coolant sensor, it wasnât latched down. Iâm thinking it was loose and causing shenanigans. I drove it a couple blocks and had no issues.
Not familiar with your car, exactly, but âlow coolantâ - there may be a sensor in the coolant reservoir and it may be bad, assuming coolant level is good? I donât think the coolant temp sensor would monitor coolant level at all.
Well. I believe the problem is resolvedâŠsometime during the overheating process, all the coolant was gone. Iput about 1.5 gallons of coolant in and used the funnel to bleed it out. Now itâs not getting hotter than about 220. and it took itâs sweet time and a good 10 min drive around town to get that hot.
Yeah Iâm pretty much going with resolved. Iâve been driving it pretty extensively and after quite a while of driving it will start peaking around 220-240 (assuming thatâs what 3/4 of the gauge means) and sometimes go just over that line, but will start coming back down to 220 shortly afterwards. Itâs not come close to red lining at all. When it getâs to itâs âmaxâ I donât hear coolant boiling or any other strange sounds. Iâm assuming at this point itâs just running like any typical old engine of the time. I do have the newer fan switch which is supposed to turn the fan on alot cooler (i believe 190 if Iâm not mistaken) so once I get that on, Iâll see if it runs cooler.