Engine bay fan

Hi all, How can I check easily if the fan in the engine bay is working correctly? I ask because recently the car has been running at a higher indicated temperature than usual. I've had it for 3+ years and it always sits in the 0 of 80 when warm (unless in heavy traffic for a prolonged time i.e. in London). Recently it has started going half way from here to the 100 line (although it doesn't go further) even when running about at 30mph locally. A motorway run keeps the needle in the usual position. I've checked the coolant level and it's fine. I've checked the front fans and they are operating properly so the engine bay fan is the only other thing I can think of unless anyone else has any suggestions? Thanks in advance

Never had the engine bay fan on my GT3 and it was never a problem. I'd suggest you look elsewhere as the temperature you're seeing is water temp and that's what the front fans and rads deal with. My guess is your rads are old and blocked up through the fins with rubbish that you can't see unless you pull off all the covers and shrouds.

Thanks for the reply. I would have agreed however one piece of key information there is that the rads were all replaced under warranty last year. Might have helped if I had mentioned this earlier I guess

Hi Gizmo, would still the condition of the rads, mine are cleaned out each yr and I'm still amazed at the amount of crap they collect.

Yes, would still check them as they could be full of leaves etc but now maybe it would be worth taking it to wherever the work was done and asking them to look at it. I don't believe though you have anything to worry about.

OK, thanks guys. Will get the hoover and home made attachment out and clear all the rubbish from the corners and see what happens. Rads were replaced under OPC warranty so I will have a word with them too

Engine bay fan only comes on at something like 120 degrees in the bay itself. I don't think it's linked to engine temperature. Clean out your intakes and make sure your coolant level etc is ok :thumb: Edited to add: It's worth taking the front PU off to REALLY clean the crud out, especially between the rads and condensors. While you're there fit some grills.

Switch-on conditions for engine compartment fan: The engine compartment fan is switched on when the engine compartment temperature is >80°C or the coolant temperature is >102°C. It hardly ever came on when I had my C2, but on the Turbo it comes on quite a lot in this hot weather. If you know a friendly Indy or OPC they can test the engine bay cooling fan with a Porsche tester.

Numerical dyslexia, however you spell it, thanks for correcting my waffle

As all above plus in this very hot weather mine is running just past the 0 of 80 when it normally runs on the left verticle. If you take it out for a good thrash in this hot weather and then park it up (in a garage if you have one ) and go back in two or three mins and switch the ignition on the engine bay fan will probably come on as the bay will have heated up. Turn the aircon fan off so the only fan will be the rear one (unless the rad fans come on also.) I also wondered if mine was working and did this today. Its the first time in three years I have heard it running. But as others have said I dont think it will affect the water temp guage.

Update: It seems that the radiator fans are NOT operating normally. Whilst they work on the "high" setting, they are not coming on on the "normal" setting - on either side. This obviously means that in traffic the temperature is getting much higher than it normally would before it is receiving any cooling from the higher power fan setting. Looks like new fans for both sides :sad:

It is far more likely to be the ballast resistors (which control the low speed) have failed. It's very common. One on each side, at the back of the PU, clipped on the frame.

Hi Richard, thanks for your input (as ever) its very much appreciated. Can you tell me, is there any way to test these resistors in situ so that I know if they are the culprits?

Sorry, I don't know. IIRC there are 3 wires going to each. I believe they are 0.55 ohm resistors, but no idea how you can test them. The manual says you cut the wires off and splice in the new resistors, and believe me, that's the easiest way to do it. The new resistors come with the plugs on the end, but it is a marathon to get to the sockets, which are up near the fan motors. Both mine went on my C2, but I didn't notice until after the second one had packed up. I guess it could be the relays, but it is less likely that the two low-speed relays would have packed up simultaneously.

That makes a lot of sense, in that I was thinking how unlikely would it be for both to die at the same time. However, with one still working and most of my journeys being motorway / A road I may well not have noticed one had stopped working and only now notice as both have died.