Hey guys,

So my coolant temp gauge cuts in and out. I have 2k on a new coolant temp sensor and thermostat. I have hot air, car seems to run fine, and starts as it did before where it does the accelerated warm-up cycle for a few minutes then idles at normal RPM.

I still have to go back in there an re check the connection, but it worked the first time I change the sensor. Could the new sensor be bad? Do our gauge clusters have problems with the gauge itself? All my searching of threads either showed bad thermostat or sensor, but both are new.

The intermittancy seems random. Sometimes it works for an entire drive, others it doesn't work for a whole half hour. On occassion, I've done an abrupt stop, and it works again rising to the middle position, other times it does not. So I'm not sure.

Opinions?

 

Update: I checked the digital coolant temp through the HVAC controller, shows 90c (194F) solid for 15 minutes after warm-up.

Can't remember correct oil temp? Anyone?

Oil temp at about 195F, pretty sure that's normal.
Edit: Car is 98.5 30v QM

 

Sounds about right, mine sits at 90.

Did you replace with the same colour sensor? It sounds silly and I am not sure of the validity of the statement but my mechanic said it had to match. I had a black one and the parts company delivered a grey one. He sent it back and got another black one from a different supplier. It didn't cost me anymore and it's weird he would put the extra effort in if it didn't matter.

 

No, there are replacement colors with updated sensors but you might only be able to use certain ones.

 

not sure if this matters or not, but mine stays on cold ALL the time. I hardly get any heat. previous owner just did timing belt and water pump, so not sure if there's an air bubble in the line or if there's another issue. He's been "out of town" so haven't heard much from him if he replaced the tstat or not...sure would be nice to have some heat this time of year. My laster winter car I complained it didn't have a/c, now i have no heat, i cant win!

 

If you get no heat, chances are it's the thermostat. You should work on that ASAP as it truly makes your car run worse and is not good for fuel efficiency. I had this same problem and the thermostat fixed it.

 

For sure, if there's no heat it's your thermostat.

I'm pretty sure the sensor I have has a green plug. I still have to get in there and check the wiring.

I'll try to remember to update this thread when I figure it out.

 

Not "for sure"

B5s have the tendancy to have clogged heater cores

 

People have the tendency to not change their coolant like they're supposed to.

 

my gauge acted wierd for a while before the check engine light came on. i got the code and it came out as coolent temp, but with the gauge acting wierd and it not overheating, i concluded it was the sensor. i went to the dealer to see what they thought and they said it probably was the sensor and that there were two types, told apart by color, blue and grey. i need the blue one and have yet to replace it. if that helps at all.