Radiator Fans - again - 986 Forum - The Community for Porsche Boxster & Cayman Owners

shlim8 · 06-09-2011, 03:16 AM

Just got my car back after getting my radiator fans checked - and my mechanic still insist that my fans are fine....

The problem (if it is indeed a problem) - sometimes only one of my 2 front radiator is on... at low speed. If the fans are spinning at high speed it's both on.

My mechanic says if the aircon is on, both fans are on. If aircon off or compressor off, and the engine is hot, one fan comes on. If engine really hot, both fan comes on at high speed.

Is this true ? I still can't figure out if this true...I seem to randomly have only one fan on... The temp has never crossed slightly more than 90 degree C, so technically it hasn't overheated. I'm just worried the series resistor is on it's way out.

(I know I had posted in someone else's thread on this, but wasn't clear on the answer. Wanted to be sure in case I overheat the box one day)

insite · 06-09-2011, 03:46 AM

each fan has its own thermostat; they operate independently from one another unless the AC is on.

madmods · 06-09-2011, 04:15 AM

Quote:

Originally Posted by insite

each fan has its own thermostat; they operate independently from one another unless the AC is on.

Just interesting learning. Seriously, what kind of engineering is this mate?! Another added possible point-of-failure or just cooling based on the Left & Right wind direction? fak sake....

shlim8's mechanic should have designed the cooling system, it would have been simpler and perhaps better imo

shlim8 · 06-09-2011, 05:24 PM

Quote:

Originally Posted by insite

each fan has its own thermostat; they operate independently from one another unless the AC is on.

Thanks insite for the reply.

Any ideas on what the part no is for the thermostat and where the thermostat is ? I re-looked at the pet catalog diagram and can't find a thermostat anywhere around the radiator. The thermostat should be measuring the temp of the coolant in the radiator (like normal cars) ??

If I have a radiator fan that seems to be on more often than the other side, does it mean that radiator is less efficient in cooling or hence fan is on, or the thermostat on the other side is not working well ??? Or water flow is less on one water pipe.... hmmm

In fact I've never had the left side fan come on without the right side fan being on (but the reverse happens).

Nothing is simple on a P car isn't it ??

insite · 06-09-2011, 05:30 PM

I think it actually measures the surface temp of the the radiator itself. The part number is 996.616.101.00. I actually have my radiators out right now; I'll take a pic tomorrow.

Dale_K · 06-10-2011, 03:39 AM

The fans in my 2000 S seem to work together. I've never noticed only one fan operating. The Durametric can bring them on in high or low but not independently. I could see if the big resistor failed on one fan you'd get a situation where both fans would run in high, when the resistor isn't used, and only one fan would run in low.

I'm not saying you're wrong, only giving my experience.

shlim8 · 06-10-2011, 08:15 PM

Quote:

Originally Posted by insite

I think it actually measures the surface temp of the the radiator itself. The part number is 996.616.101.00. I actually have my radiators out right now; I'll take a pic tomorrow.

That's actually the series resistor... I'm going to order those online and replace it just to be sure...

insite · 06-11-2011, 04:56 AM

They do call it a resistor, but it looks like a thermistor to me. I bet yours has failed.

gery67 · 06-30-2011, 09:47 PM

Quote:

Originally Posted by shlim8

Just got my car back after getting my radiator fans checked - and my mechanic still insist that my fans are fine....

The problem (if it is indeed a problem) - sometimes only one of my 2 front radiator is on... at low speed. If the fans are spinning at high speed it's both on.

My mechanic says if the aircon is on, both fans are on. If aircon off or compressor off, and the engine is hot, one fan comes on. If engine really hot, both fan comes on at high speed.

Is this true ? I still can't figure out if this true...I seem to randomly have only one fan on... The temp has never crossed slightly more than 90 degree C, so technically it hasn't overheated. I'm just worried the series resistor is on it's way out.

(I know I had posted in someone else's thread on this, but wasn't clear on the a
nswer. Wanted to be sure in case I overheat the box one day)

yes it true that when engine is eally hot both fans on at high speed.

shlim8 · 07-04-2011, 11:22 PM

Quote:

Originally Posted by gery67

yes it true that when engine is eally hot both fans on at high speed.

Yes, that's consistent to my car too. But now I've finally had a situation where only one fan is on at low speed with the a/c compressor on. And I've got one fan coming on at high when I start up from cold in the morning. So I'm sure I've got a problem (or two). Going to change the series resistor this friday.

Hopefully this will give me more consistent water temp... and colder a/c

shlim8 · 07-09-2011, 06:29 AM

Got the resistor replaced. Been running around for a day now. Looks like both fans are on now, as san rensho noted - it looks like the resistor was the problem.

Its probably a combination of cleaning the radiators (10 yrs work of junk!) and both fans coming on - the temp is now quite consistent at slightly pass 80C. But no chance to push the car yet as I'm still bedding in the front brakes after converting to the S front brakes.

SF-Rockster · 07-10-2011, 01:29 AM

Quote:

Originally Posted by shlim8

Got the resistor replaced. Been running around for a day now. Looks like both fans are on now, as san rensho noted - it looks like the resistor was the problem.

Great news!
Can you post up the P/N for the resistor ?

Nexus-6 · 07-10-2011, 11:22 AM

Quote:

Originally Posted by SF-Rockster

Great news!
Can you post up the P/N for the resistor ?

Second this. Thanks!