Timmer

I have taken my C4 throught heavy rush hour traffic for the last few days

in stop/start traffic, the oil temp seems to get very hot before the fan cuts in.

Regular driving see the temp at the 8 o'clock and below mark, but sitting in traffic for the best part of half an hour this morning, the needle went up to the 10 o'clock line before the fan cut in and brought the temp back down to nine o'clock.

I have read elsewhere the the fan should have a two stages - does mine seem to be only cutting in a the high speed threshold?

Ambient temp circa 17 degree celsius.

Questions:

1) what temp do the 8 o'clock and ten o'clock positions correspond to?

2) should I be worried that my temp goes to ten o'clock in traffic?

cheers fellas,

Timmer.

Christer

Do you know if your oil cooler opens (It does sound like it does but thought I would check)? If it does, it sounds to me like your fan as you rightly suggest only cuts in at the high speed setting, as the low speed should activate just past the 9 o'clock position. You need to get that fixed but would I be worried about occasional 10 o'clock temps whilst you get it fixed? Personally no, but I would get it fixed ASAP.

Johnny G Pipe

This is a common discussion point, and is well worth a search.

This link should answer most of your questions
http://p-car.com/diy/fan/index.html

The car is probably completely happy at these temps - which is why the owners manual tells you to start worrying only when it goes into the red..but we like to worry about things on these forums - and there is some chat to the effect that running hot regularly may shorten valve guide life..

My car behaved the same - my slightly lazy solution in the end was to fit a switch to bring in the hi speed fan when I wanted - summer traffic jams, on track etc. Its pretty easy to fit..

FWIW,I think your oil cooler thermostat is working, if not, you wouldn't see the temp drop when the fan cuts in.
My own experience is that prior to my thermostat dying completely recently , the car ran just a little hotter in general than it does with a new thermostat..I think it was only opening partially for a while..I have been wondering if that was confusing the temperature sensor at the fan?

DarrylH

As you'll see in Randall G's most excellent treatment on p-car, I'd bet on a perished low speed resistor - sounds to me as if your fan isn't coming on until the high-speed threshold. Easy to check, you'll see how in his writeup.

Johnny G Pipe

I just converted Randall's temperatures into real money: Apologies for the crap diagram..each line corresponds to the markers on the dial (so 90 is actually a little lower than shown)

150
.....\\

120
......\

90 --

..../
50 /
....0

For reference, my friends moderately tuned Evo runs up to over 140 C on track..