Today while idling in traffic in the mid 90's and sunny I noticed my temp gauge read four bars for a moment until I was able to start moving again. This is the first time I have ever noticed it read four bars and was wondering if it is safe for the car.

My coolant levels are okay and had the system flushed and bled about 15k miles ago.

My guess is possibly the thermostat? Or is it something I should not worry about it if I don't see four bars again.

 

4 bars is bad. My car has never gone over 3 bars unless something was wrong ( I also live in FL where we have pretty brutal summers ). I had a thermostat that would work properly for a while and then it would stick closed. If you havent changed it, its probably a good idea to do that. Make sure your fans are coming on.

Ignore the modifry on the right unless it applies..

 

probably some small pocket of air in the system.

 

4 bars can happen, I wouldn't call it the end of the world, but I would be concerned if it was for a period of time after you started moving again. As you see the OEM gauge is worthless, so the Modifry fix is a must have for an AP1. I see 4 bars quite frequently, but I have the Modifry fix

 

Thanks for the feedback, the temperature chart is very helpful.

Would topping off the coolant through the overflow reservoir cause air in the cooling system? Or when removing the IAC valve and a little bit of coolant leaks out, would that cause air in the system?

Also if the thermostat failed and never kicks the radiator fan on, would the temperature not exceed 3 bars while the car is moving due to airflow and only overheat during idle?

 

adding coolant to the overflow reservoir would not cause air in the system.

removing the IAC will introduce air into the system.

if the tstat is stuck close the system will over heat even if moving.

 

I would try to bleed a bit more fluid/air from the system, chances are there is a small pocket of air still in there. Not likely the thermostat as they either work or fail in most cases. Replacing the stat would be the last resort once you know all other parts are working properly and the system if bled of all air. If the overflow tank ever went low you could have sucked in some air maybe after the last service.

 

OP,

Since you state that your engine temp went up while you were sitting still and then went down after you started moving I would strongly suggest that you check your electric cooling fans. That is a simple easy check, and IMHO the most likely cause of your problem.


AE_Racer,

I don't understand the Modifry temp gage mod. In a stock AP1 normal running temp is 3 bars @ 235 degrees. With the Modifry mod the 6th (and last) bar = 235 degrees. So with the Modifry mod, how does one ever know if their engine is overheating ? The exact problem that the OP wrote about would never be known with the Modifry mod.

Am I missing something obvious ?

 

The chart shows 3 bars (OEM) as 160*. The Modifry unit adjusts the scale, since no engine will survive the 273* max reading on the OEM gauge.

 

Duh... I was confused by the different color of the first bar. My bad

So, what is the desired operating temp for an AP1 ??