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Low coolant warning, after changing sensor


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Hi guys, any input welcome on this one.
I have a 2006 Cayman S manual.

My coolant was a bit low, so I topped it back up (the car took a litre) and the light stayed on.

I took it to a local garage who said the coolant cap may be to blame for the loss, so changed that and also had the coolant level sensorchanged as it was considered broken (possibly cooked when the coolant level dropped?)

The light on the dash and the message remained, so my mechanic took the car to OPC who used a Porsche diagnostic to clear the code, then read the code again. Apparently it is throwing no codes, the level sensor is fitted properly and the wiring looks sound.

The garage/Porsche have suggested that the fault could be a faulty instrument cluster, which are mega-money from POC. But, the local mechanic says he could remove it and get it sent away for testing (and possibly repair).

I am having the car back tomorrow while I have a think what to do.

Essentially the car seems fine, but the light won’t go off.
Am I missing something obvious and what would you do in my situation?

Thanks all,

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Have you tried just disconnecting the battery for an hour or so and seeing what effect that has?


If you have a burp valve, maybe run the car with it open and see if that has any effect on the coolant level. The new coolant reservoir cap presumably has '04' as its last two digits?

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Thanks both.


Its not just the light, the dash reads something like 'low coolant level' (I forget exact wording), and shows a little icon of a water container.

Would this rule out the temp sensor?


If I disconnect the battery, will I get an alarm problem?

I could try that.


Im not sure if I have a burp valve - the mechanic fitted it (its all hidden under the carpeted shelf in the cabin).

I presume its the black one in this stock photo:


Having said that, the mechanic told me he tried filling and emptying the header tank using a big syringe, but full or empty the light kept coming on.


All ideas welcome! I will try disconnecting the battery first, if no alarm issues are likely.




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Yes, the burp valve is the black thing next to the blue coolant reservoir cap. Carefully lift the metal piece to the upright position and leave it there until you've run the engine to operating temperature. Make a note of the fluid level before and after.


Re disconnecting the battery and the alarm, there should be a procedure for that in your handbook, failing which, do a search on here or Google.


How many miles has the car done and has the water pump ever been changed to your knowledge?

Edited by wizard
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Hard to say what it might be. It could be that the coolant was under-filled or, alternatively, it could be that you have a leak somewhere. Equally so, it could have been a defective coolant reservoir cap ('04' being the latest) ... or it could be a defect in the instrument cluster. It could be that you are getting an incorrect temperature reading.


It's always best to rule out the easier things before moving on to dismantling the dash.


I have a 986 so I don't know the layout of your engine. If there's a leak at the water pump, you'd normally see a (white) residue in the vicinity. 100,000 miles on the original water pump (if it is) is perhaps stretching it.


If you are intent on 'burping' the cooling system, monitor the engine temperature and low coolant warning whilst you do it and, naturally, check the coolant level when the engine is cold. 


See JFP's post immediately below ... and his to you. He is an authority on Porsches. As he says, check that your fans are functioning as they should. If yours is the same as the 986, the fans at the front of the car are two-speed.

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It's very helpful to be as precise as possible. You have only now mentioned that the light is blinking. If one naturally assumes that not to be the case,  the 'engine coolant temperature too high' would be a factor.


Let us know how you get on.


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Sorry, I thought I had mentioned that. And I agree with your post. It is blinking slowly at the end of the rev counter. Now that you are furnished with this information, does it give you new ideas? Thanks for your input thus far 

Edited by Gerlewis
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Nothing else springs to mind, other than visually checking your coolant level regularly and perhaps inspecting the water pump.


Depending upon how mechanically adept you are, removal of the serpentine belt which drives the pump and checking it for play/residue is a straight forward process on the 986. I don't know if that's the case with the 987.


I'd still focus on ruling out the more mechanical elements before considering removal of the instrument cluster.


Disconnecting the battery to see if that clears something that has been stored, and burping the system will do no harm at all. From memory, burping calls for the heater to be set to high and for the front fans to activate. I'm sure you can find the procedure through Google.



Edited by wizard
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I dont use the car for commuting and this is the busy time of year for my business, so I intend to try all of this over the next few weekends.


Then I will report back.


If no joy,  I will try getting a second opinion from another mechanic.


Thanks again for your time



Edited by Gerlewis
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