Vinnx

So today I was driving along, there was pretty heavy fog, I turned the car on, and did 2 laps around the community at very low rpms to warm up before I head off. I had the inside air temp set for heat, turned the fan about mid way, and turned on the rear defogger. About 15 mins into my journey when I looked down to check my speed my temperature gauge was in the RED, nothing felt different with the car, but I came off the gas and slowed down and made a right turn and pulled over the side of the road and shut the car off. At this time I realized my hazard lights don't work.. I touched the top of the hood, but it felt cold, then I opened the hood and that too didn't seem to hot :/ I checked my oil and that seemed fine, just yesterday I added 1qt of Mobile 1 Synthetic oil in. Couldn't check the coolant cuz the car was hot. But after the car sat for a while I started it, and after a while the temperature started to rise then fell a little, then I turned it off again. Now I turned it back on and went for a test drive, the temperature gauge was... moving around slowly I watched it rise to 3/4 to overheat then fall back to the half way point over the course 4 seconds. So I drove the car back home and only twice on my journey did the gauge move weird, it rose a little then fell, going about 40mph. But then on the main road I just said screw the gauge downshifted into third and gave it some gas to pass some trucks and went about 80 mph, and the temp didn't even budge! I slowed down, made my left, floored it in second, took it to red line and again the temperature didn't budge! But when I entered the community, after about 1 mins of driving at 25 mph the temp started to rise then fell a little, then started to rise while I was pulling in to park.

Ok, so I feel pretty confident it's probably faulty wiring or temp gauge, or sensor. But any ideas of how to diagnose the problem my self to figure out where the problem lies? I really don't want to drive the car knowing my temperature gauge isn't working properly..

lazlong

1. Push and hold the trip/reset button
2. Turn the lighting switch on
3. Turn the ignition to ON(II)
4. Within 5 seconds, turn the lighting switch OFF, then ON and OFF again
5. Within 5 seconds, release the trip/reset button, then push and release the button 4 times

The beeper sounds 5 times. Then all the indicators blink. Then the odo/trip segment blinks 5 times. Then all the needles sweep from min to max back to min. Then it will run a communications check and display either all 8's or the word error. 8's are good, error means the connection between the cluster and ECM/PCM is bad. If anything doesn't work properly in test mode replace the cluster.

Vinnx

Ok I tried that 4 times word for word and nothing happened.. maybe I'm missing something?

Any ways I took the car for another test drive, took it around the roads, went to 70mph held it, took it into the high rev's slowly a few times, and nothing happened... the car felt fine, and the temp didn't shift at all. Then after all this I took it around the neighborhood around 20-25 mph, and the temperature started to climb, then drop, another lap, it rose fairly high, then dropped. Something is faulty ><

lazlong

I just tried it and it works fine. Use your right hand to hold the trip/reset while you work the lighting switch and ignition. And by lighting switch I mean the one for exterior lights, not your dome light.

blackrandom

I tried this on my car too and it worked, I had to do it a few times because the trip/reset button wasn't working very well. I got all communications working properly, still have to check for a bad head gasket though which I hope it is not

BlueEM2

iTrader: (1)

It's probably not a faulty sensor. You probably have air in your coolant system. You need to bleed the coolant system and find out how the air got in there. Is your overflow at the correct level or is it too full ? too empty ?

Don't just to a head gasket conclusion when it could just be a rad cap

harpf

I have the same basic problem - erratic temperature indications 2005 Honda civic 1.7.

Started by changing the thermostat (no help). It seems to get hot and cold to fast to be engine problem esp with the rapid drop in temp.

My next step was washing out the sensor connector with 'boe shield' T-9. The fault has been not seen since (half hour test drive, via subdivision, hiway, city and back. If it comes back, my next step is to put a thermocouple at the temp sensor and run the wire back into the car to see if the intermittent 'hot' indication is real.

- If temp indications are real I'll change the cap, and make sure the overflow system is working correctly.
- If the indication is the problem I'll change the sensor.

Robdynamite

Have the same problem did that solve the issue? Using the "bowshield" where exactly did you spray the bowshield?

I have a service light on which started to come on but goes on and off.


Codes:
PO135 - O2 sensor Heater Circuit Malfunction Bank 1 Sensor 1
PO134 - O2 sensor Circuit No Activity Detected Bank 1 Sensor 1

noJeepshere

I have a similar problem to the OP, the gauge will climb towards the red zone only around idle. I tested it in a parking lot today, let it sit (after fully warmed up) and waited for the fans to come on (2 min) yet the needle climbed, even after I turned the heater to full hot. There wasn't even warm air coming out of the vents. I revved it to 2,500-3,000 rpm and the vents suddenly became hot and the needle dropped to where it should be.

Back at idle the vents cooled off and the needle started climbing again, so I went to the top of a hill and let it warm up again (needle in top half of range) and coasted down the hill for nearly a half mile (I have a manual trans so it's ok) and it did not cool off until I put it in gear and let it engine brake at 3,000 rpm, at which it promptly cooled down to normal.

I know it's not lack of cooling capability, as I can climb a mountain pass with it in 3rd gear, 3,000 rpm, full throttle, a/c on, 95* day, and the needle will barely get over the halfway point. I'm thinking either air in the system (flushing on Tuesday with new thermostat and rad cap) or a bad water pump. I'm hoping it air in the system and flushing it will fix it.

Matt_75

Air in the system or a blown head gasket. Try to bleed it and see if the problem returns.

noJeepshere

Definitely air in the system. When I pulled the thermostat housing, the rubber gasket/o-ring was brittle and cracked. Not sure what happened there... and the system had green coolant in it, which I guess was put in with a head gasket replacement. Funny the things you learn when you start digging... I made sure to flush it well and put Asian vehicle specific coolant (safe for aluminum engines) in it, with a new cap and thermostat. After getting all the remaining air out of the system and taking a test drive, I let it sit nearly a 1/2 hour with no issues at idle.

anibis

I hope the problem doesnt return, but knowing how these cars eat through HG's I would bet it will.

Debbie Van

...Oh wow, my car exactly! Driving around in town, car is fine..get on highway for 10 miles or so, temp gauge starts rising, I'm desperately looking trying to figure out where to pull over..it's never been hot under the hood

Jimmyswart

Mine is 01 doing all the same things only one difference. After mine has gone through all the up and down. And I shut it off it won't restart without cleaning the brand new plugs which appear to be fuel fouled. This has new head gasket,new radiator, new thermostat, new cap, new water pump, new reservoir. No signs of leaks and has been bled numerous times. Head and block were guaged at gasket replacement. And I did the dash reset all good. Pressure test holds for an hour with next to know let down. I'm a master tech and at a loss.

Debbie Van

Maybe you need new rings..

xRiCeBoYx

iTrader: (22)

Not if a pressure test held for an hour with no leakage. I'm assuming cylinder pressure (leak down) test, yes?

Dumb question. Did you check the temperature sensor and/or bleed the coolant 100%?

HondaCvcHybrd07

I have a 2007 Honda Civic Hybrid. I am having the same problem with the temp guage. I've re-done the head gasket because I did have a blown head gasket. I've changed all the thermostat and the sensor. I test drove it yesterday. Drove it to the gas station (20 min) and idled in line ... it did fine. Left the gas station and drove it for a bit (maybe 15 min) and the temp guage starts to rise slowly first just a notch above half way. Drove a little more and it climbed two more notches and then dropped back down to normal. It never actually go all the way. When I got home, I parked, left the car running and popped the hood. The engine felt normal in temp after driving it. I did let it run for a bit before I headed to the gas station, checked the engine .... normal temp (didn't seem any hotter than usual). Like I said, I've changed out all the sensor and thermostat but the guage still does it's crazy thing. I am getting ready to put it in the shop this week if it keeps doing this. It's hard to drive the car when you cannot rely on the temp guage. Could this be electrical?

Robertlx

How did you bleed the radiator?