Normal Operating Temperature

[dr_karlb]

I have owned a 2001 C4 Cab (7,000 miles only!) for the past few months. Now its getting warm in California, i see the engine temperature fluctuate from the 8 in 180 on the gauge, to above the 0 in 180. Is this normal ?

I vacuumed out a few leaves from the bottom corner of the radiator, but it seems to be the same.

I checked the fans when the AC was on and they both work... they seemed to blow outwards... is this normal ?

I havent heard them run without the AC on at the slow speed.. when do they kick in for the different temperatures and different speeds ?

Is there a fuse or relay to check ?

The coolant level looks fine thru the bottle.

Sounds like other folks see something similar.. but is this normal behaviour ?

Any advice ?

Thanks

[djantlive]

How is the condition of the coolant. It's supposed to be lifetime but it may be good to check if it's dirty or simply running low.

[1999Porsche911]

Normal operating temp should be around 192 - 196. Most 996's show the needle just a hair to the left of the "0" in 180. When the needle gets past the "0", you are pushing temps above 210. This is fine for hard driving but the temp should drop back to normal when you back off.

[wwest]

Fans should come on independent of A/C operation. Assuming not enough forward speed to provide sufficient cooling airflow the fans should run on low speed as the coolant temperature rises to the first "limit", and then to high speed if the temperature continues to climb. As it certainly will on a hot day with the additional "load" of the A/C.

The airflow from the front radiator fans should be out the bottom just in front of the front wheels. If you are feeling reverse flow then it is possible the fans are installed backward, or possibly reversed voltage polarity.

From experience I can tell you that if its a hot day and you're using the A/C and the low speed has failed by the time the system reaches the higher temperature and turns on the high speed mode it is a little too late and the car will now run slightly overtemp.

[dr_karlb]

Thanks all for the replies.

I re-checked the fan air flow and it does exit thru the opening in front of the wheels. I think i just felt the back-pressure come thru the front vent openings.

I couldnt see the low speed fans enable at all when i let the car idle at the gas station.

When the temperature gauge reached near the right side of the "0" in 180, the high speed fans kicked in (while i was stopped)

The temperature is fine when im driving... its between the "8" and "0" in 180.

At stops, it slowly creeps up.

Im guessing that the low speed fans are not kicking in at all, so the high speed ones are keeping the temperature at i higher level.

Any ideas on troubleshooting the low speed issue ? It there a fuse or relay to check. ?

[umn]

...

I havent heard them run without the AC on at the slow speed.. when do they kick in for the different temperatures and different speeds ?

...

From memory:

The fans work on low speed:

Always when the AC is switched on

or

if the coolant temperature is >100 Celsius

The fans switch to high speed:

If the coolant temperature is >105 Celsius

Cheers,

Uwe

Edited March 15, 2005 by umn