Cooling Fans

[jetbox]

Hi,

I am trying to understand how the front cooling fans should work... Please help. I have done a search but still have a question.

I was putting my C4 in the garage yesterday and I noticed the fans were running. I got out of the car to check and found that I could only feel/hear the driver side fan running.

Should the fans run on both sides of the car at the same speed (speed 1 or speed 2) or can they run at different speeds. The aircon was on and the car does not appear to run much hotter than 80 degrees.

thanks

Jetbox

 

[Richard_Hamilton]

You didn't find this then: http://www.porscheclubgbforum.com/tm.asp?m=330170

They should both run at the same speed. Most likely one of the low-speed ballast resistors is faulty, but it might also be a relay.

 

[jetbox]

Hi,

Thanks Richard.

Could not see any mention of fans at different speeds. I will see if OPC will fix under warranty..

many thanks

Jetbox

 

[Nick_USA]

The 986/996 fans run at two speeds and as previously mentioned should run the same speed on both sides of the car.

btw the 987/997 fans are variable speed.

 

[johnk]

the fans should both be running at whichever speed it requires, with aircon on the both run at low speed, but you sometimes find that one of the fans fail on low speed this in turn then causes the system to up the speed to high and both fans end up working but only on high... opc should be able to system test these with piwis by testing the speeds in drive links

 

[jetbox]

Hi,

After some more playing and diagnosis I have confirmed that its the l/h fan that will not run on low speed. r/h will run on low and then as the car gets hotter both run at high speed. I have checked the fuses and now swapped the relays from now 1 position to no.2 position with no change to the fault.

I could give up and take to opc under warranty but would like to fully diagnose the fault as part of getting to know and understand the car better. I guess the next step is the low speed ballast resistor or a wiring fault. Where is the ballast resister located and can it be easy swapped from side to side to prove the defect.

thanks

Jetbox

 

[Richard_Hamilton]

You would struggle to swap the ballast resistors side to side. Even the workshop manual says to cut off the wires and splice in the new wiring. The resistors have plugs on the fly leads, but you have to dismantle half the front end to get to them. They are a really common problem (I had to fit two to my old C2) so I would suggest just going ahead and changing it.

(Photo courtesy of Loren at RennTech)

 

[jetbox]

Richard,

thanks, just been searching and found the post from Loren on rentech with the location... looking at the cost of the resistor my next step is to call opc to book in car for warranty fix.. I have learnt alot in the process though. May as well use the warranty before it expires...

many thanks