Coolant level warning

[Jdw1222]

2014 Cayenne -V6

For the last week the car has been flashing low coolant level and the temp gauge pegs for maybe 10-15 seconds when we first start the engine. Obviously a false reading. Coolant level appears to be fine. not sure why its getting both a low coolant and high temp as I would think these are 2 different sensors. after this happens the temp reading appears to go back to normal and doesn't have any other warning while driving, but seems to happen every time we start the car.

ANy thoughts?

[P2C4]

2012 Cayenne Turbo -- I've had the same issue.  Every few weeks, typically as I begin driving before reaching operating temperature, the low coolant level warning message flashes slowly, and the coolant temperature gauges (both digital and analogue) will run up to 255 degrees F.  Then if I touch the brake, or the accelerator, or hit a bump on the street, the temperature gauges revert to normal levels (201 degrees).  I know the coolant level is not low. And several time when it has done this, the engine isn't even up to operating temperature yet.  Happily, the digital oil temperature gauge in the instrument cluster never seems to show these fits of variation, and is always in the reasonable range.  There is no regularity to when the low coolant level and high temp gauges act like this. But they always reset quickly, within a few seconds if I barely touch the brake or accelerator. 

 

Coolant and coolant pump were changed by an indi shop in October, first time it acted up like this was in February (winter here in Utah).  Next time it did it was in May. Then a several times in June, and now a couple times in July. 

 

Is it the gauge? A temperature sensor? The engine coolant is definitely not overheating when it does this. 

 

Any suggestions?

Edited July 27, 2022 by P2C4

[ophthodawg]

Thanks for your post

 

i just had that same experience with my 2015 Cayenne Diesel, starting in subfreezing temp before the engine was warmed up, cluster showed a message indicating low coolant and warning of do not continue driving ! I wasnt driving yet so i just turned off the ignition, glancing at a pegged engine temp ! 

 

i stopped the car and restarted it and everything was fine with an engine temp at 93° I couldnt open the hood because it was frozen … ill check coolant as soon as a can open the hood but the truck was fine driving … 
 

very concerning but it looks like a false reading … 

[MFDoom72]

it's 1 of 2 coolant temperature sensors and the auxiliary coolant pump 

replace all 3 and the problem will go away -- had this issue for a short time on my S Hybrid, replaced the 2 sensors (one is on the back of the engine ) and the auxiliary water pump ( which can be had on ebay for 1/5 of the Porsche price, from the OE manufacturer ... Pierburg ).... coolant sensors are cheap all over the net 

[vsurg]

related, but not identical issue...2014 Turbo S with "Coolant Display Defective" warning. I have fixed the problem but enroute, I did not know what the normal temperatures should be. I assumed, that since the coolant level was 'normal' when the warning came on and returned to 'normal' when I turned off the ignition and restarted, that the problem was the temperature sensors (front and rear). These were replaced to no effect. I discovered that the thermostat also has a temperature sensor and that replacement of it was the next step. Not being able to stomach that bill ($2400), I did it myself. It is still early but it seems to have fixed the issue but, I discovered that the 'normal' temperatures I was seeing before were actually too low. I now get to 200deg F in about three miles and it stays there. Before, it wouldn't get above 170 on average. I have not been able to get a spec sheet on what the actual 'normal' temperatures are supposed to be. Any assistance here would be welcome.

[P2C4]

From the digital readout on my 2012 Cayenne Turbo, the normal coolant temperature on my care is 201 degrees F.