Hey Guys,

I have a strange issue, my coolant temp seems to going up and down, when driving it around it around 70c-80oc when i leave it idle for 5 min or more it will slowly go to the middle. Well not entirely the middle just a slight bit over the middle bar but still on it. The HVAC (code 49) will show it rising, i've seen it go as high as 97c on the HVAC, but the temp gauge does not move past the middle. Any ideas on what might be the problem? Also is it normal for the coolant temp to get this high when on idle?

I think i might replace the thermostat and coolant sensor, anything else to check?

 

It is not unusual for temperature to fluctuate, part of why you dont see the gauge move is because it is quantized, not continous, ie it will only move up for example to the next notch when the temp reaches a threshold, I think 100 or 102. If it is not moving in entire segments, you could have either of the common coolant issues (sensor or cluster). Although you could have an issue, I am not sure you do. What does code 51 say? That is the smoothed coolant temperature number. Are you r fans kicking on? Carefully look to see that they do, or check the fuses atop your battery.

 

51 is a steady 90, and fans are kicking in

 

Sounds fine to me then....but I am sure more informed members can weigh in. Part of the reason like I said of the discrepancy is for exactly the reason you have a question: the gauge only moves when changes reach certain thresholds, so people dont get bugged out by normal fluctuations.

 

i been posting this issue before but i will say it again just to get this more clear.
new thermostat, new radiator, new timming belt. new water bump and tensioner.
the temp needle will stay at mid in normal driving. but in heavy traffic or if i let the car idle for like 5 minutes or so.. the needle will reach the first notch after the mid and the fan will turn on so the needle will come back to mid. and it goes so on.
HVAC No. 51 always reads at 90 degree for engine oil temp i think.
HVAC No. 49 is from 93-98 all the time in normal driving. It will reach around 103 degree when the needle reachs first notch after mid and the fan will kick in to lower the temp back to around 96. 97...... and needle will come back mid...


i been doing a lot of researching... seems like it is normal for a lot of TTs out there.. for some of them... the needle will STAY at first notch after mid in regular driving... ppl always telling me it is normal... so don't worry about it.

 

thanks, problem with mine is it's running 68-75 during driving, i think the thermostat is stuck open or whoever owned the car before me put a cooler one in. Thanks for the advice guys.

 

replaced the thermostat today, it's now stays in the middle on the gauge and fluctuate between 88-94 on code (49).