Engine Compartment Fan/Light

[pontypool]

ETA Hello - long time lurker but first post! This site was invaluable sorting out my roof's low hydraulic fluid problem out but something new has cropped up....

I have searched all the relevant threads alredy but nothing seems to quite fit the problem on my 2000 C2 cab tip (UK car):

1. After driving for about 10 minutes the engine compartment fan comes on (at around 75 degrees C according to the digital read out)

2. After a few more minutes the temp guage starts flashing slowly

3. If i turn the car off and on again and continue my journey the flashing light waits another 5 or 10 mins before coming on again (the fan reamins on)

I am 100% topped up with coolant and it is not losing/lost any at all

The sensor is not hanging down by the exhaust but is sitting in its slot between the air intakes

The fan shuts down a few minutes after parking

The coolant temp sits dead upright on the dial and the digital read out gives between 87 - 93 depending on traffic conditions - not over heating at all

When I disconnnect the plug on the fan to stop it working the light still waits 10 or 15 mins before it starts slowly flashing.

What could be going wrong here????

Edited November 3, 2009 by pontypool

[Loren]

:welcome:

Have you cleaned your front radiators?

Also, if everything else is good (actual temperature readings should be verified with using the Durametirc software, a PST2, or PIWIS tester) then you could have a stuck thermostat.

[pontypool]

:welcome:

Have you cleaned your front radiators?

Also, if everything else is good (actual temperature readings should be verified with using the Durametirc software, a PST2, or PIWIS tester) then you could have a stuck thermostat.

Thanks Loren, but would partially blocked front rads contribute to a dodgy engine compartment fan?

I left it idling for a very long time after a spirited drive and the temp crept up to 103 then the rad fans cut in as they should and the temp dropped back down. Seems to me that the coolant temp is reading ok but something esle is amiss...

[Loren]

The engine purge fan should only run when the engine is too hot. If the radiators or the thermostat are not working properly - then your car is too hot.

The actual values testing with one of the tools I mentioned above would verify whether the engine is really too hot or the their is a sensor/DME problem.

[pontypool]

Having watched the guages like a hawk:

1. Engine compartment fan cuts-in when coolant temps is exactly 75 degrees C

2. Red light starts flashing slowly when coolant reaches exactly 93 degrees C

3. Coolant temp will not continue to rise on dial or digital read-out

4. Coolant still sitting on MAX level

5. Front rads not blocked with leaves

6. Engine Compartment temp sensor in the grommet correctlly.

Is there a way to tell if the engine compartment temp sensor is faulty without PIWIS?

[Loren]

Having watched the guages like a hawk:

1. Engine compartment fan cuts-in when coolant temps is exactly 75 degrees C

2. Red light starts flashing slowly when coolant reaches exactly 93 degrees C

3. Coolant temp will not continue to rise on dial or digital read-out

4. Coolant still sitting on MAX level

5. Front rads not blocked with leaves

6. Engine Compartment temp sensor in the grommet correctlly.

Is there a way to tell if the engine compartment temp sensor is faulty without PIWIS?

Not really - you will need a tool like the Durametric software, a PST2 or PIWIS to get actual sensor readings.

[pontypool]

I replaced the engine compartment temp sensor with a brand new one from Porsche and makes no difference, the light still start flashing on exactly 93 degrees (for example when sitting in bad traffic) , but the coolant remains on MAX and the coolant temperature is not doing anything out of the ordinary - the car is not over-heating.

Next thing to change is the coolant level sensor, but where is it and is it a simple DIY?