I posted a couple of days ago about my alternator replacement. Since the replacement I have been having a wierd issue with the car. It act's (the gauge only) like its overhearing, the needle moves from the normal temperature and then spikes to the top, the buzzer goes off and the needle stays there for a bit. Sometimes the needle resets itself and goes back down to the normal level. If the car sits at a light, the needle wilkll slowly drop back to the normal range. I will take off and within seconds the needle shoots back up and buries itself. It cycles this drop and bury issue several times, until I get an almost constant chiming at times.

The temp gauge will even be buried at the top hours after I turn the car off; although, it is always normal when I start the car in the morning. Before I drive a couple of blocks though, it will be right back at the top doing the dance.

Any ideas? I already replaced the thermostat in the car in the hopes that would fix it. The belt is on the pump and it appears to be pumping. The car is definitely not overheating.


TV

 

Make sure your radiator fan is operating properly. Let the car idle for about until it comes on or the car over heats.

 

Yeah I tried that, the car just sits there at the correct temperature as far as I can tell. I have actually driven the car several hundred miles with the gauge doing this. Bumper to Bumper traffic the car goes from "overheating" to normal within 10 to 15 seconds.

 

Ok, I got into the car this morning, checked the wiring going to the temp sensor and verified they looked ok. I turned the key on to ACC and the gauge jumped to H. This is after the car has sat all night long, so there is definitely something ***** with the sensor maybe? Or could it be the gauge itself?

 

Any additional information? I find it hard to believe that nothing was wrong with the cooling aspects of the vehicle prior to the alternator replacement. Since the replacement the gauge is all wacky, I do know that the previous owner replaced the Timing belt 15k miles ago, but I am not sure if the waterpump was replaced.

I did notice some "steam" coming from the vehicle today, so I looked and there is a bit of coolant leaking from the vehicle. That could be run off from the replacement of the thermostat replacement yesterday or something isn't quite tight enough. I am going to go trace cabling and retighten some bolts to ensure everything is nice and snug.

 

I just went out to the car, pulled off the rad. cap, started the car and ran it until the thermostat opened and the water started flowing. During this first initial time there were some bubbles coming from the system. After the therostat closed the first time a few more bubbles came out until the thermostat opened again and began circling. I let this happen for another 5 minutes or so (total time now is roughly 10 minutes) and then capped it. When I started this the car was on H after 2 or 3 minutes the needle began to drop and within 30 seconds went from H to normal. When I capped it, the needle shot up to H within 5 seconds; although, it did not happen again when I repeated it. There was also no issue with pressure build up on the hose immediately after capping. Revving the car did not cause an immediately pressure build up either.
While the car was running I pulled the temp sensor wire and the car immediately began running rough and the fans kicked on. I plugged in the sensor and the car ran fine again and then turned off the fans after slowing them down first. When I pulled the plug the second time the housing broke of of the sensor. I am going to replace it to fix the broken housing and see if that resolves the gauge issue. The fans never kicked on to cool the car during any of this, but I assume that since it is coming on when I pull the temp sensor they are working.
I also could not find the coolant leak, there were no additional drips from the vehicle while it was running.

Could this be a gauge related issue such as posted in the forums elsewhere? IE, I need to take out the cluster and resolder the panel? I am just trying to think ahead to what may be next and plan out the repair.

 

There is air in your system, and it need to be bled to remove all air bubbles. It need to be filled to the top. Watching the bubbles is not solving the problem

Revving the car is having no effect on your coolant system.

Your gauge cluster is not "wacky." They are soldered when the speedometer functions fail.

If your car is leaking a fluid, open the hood and look for where it is coming from. You are there, not us.

 

Ghost,
I understand that there was air in the system, I purged the air by letting the car run until the thermostat opened several times and cycled the system. I watched the water circulate for several minutes before I capped the system. It ran for about 10 maybe 15 minutes with the cap off, I stopped seeing bubbles after the first 5 minutes. I do not see a bleeder valve on this car anywhere ans this is the only other way I know of purging the system. If you know a better way please let me know.

I saw several dripped that I am sure is related to me replacing the thermostat filler neck yesterday. I retightened the bolts and have not seen another drip.

The fan is coming on and running for what seems to be the correct amount of time. The car will sit there idling for 3 to 4 minutes, the fan will kick on for 1 to 2 minutes then power off. This cycle continued several times and while the gauge was on H.

The temp gauge is definitely wacky, maybe not the entire cluster. Although my gauges HAVE acted up several times where all the gauges stop working for a short time and shot up or down completely. Now it is just the temp gauge doing this.

FYI, I have only had the car 4 weeks and have never owned a Neon before. I have worked as a mechanic for years, I am simply asking for some assistance with a car whose issues I am not familiar. Thanks!

TV

 

It takes long than 10 -15 minutes to bleed the coolant system. Double that time for better results. The tool used to pressurize the system is not that expensive here. All this information can be found in a chilton or Haynes manual. I'd focus on the coolant system before addressing the gauge cluster. Air in the coolant will effect the readings at the gauge cluster.