I have read the DIY on p-car for this recommended mod. It looks fairly straightforward, depending on switch location.

However, shouldn't this high-speed fan come on anyhow at the appropriate temperature? Accordingly what is the true purpose ... possibly just getting things cooled off a bit earlier so that it doesn't get into that irrecoverable '10:00' situation when in stop-and-go traffic?

Thanks,

 

Yes, you've answered your own question.

The purpose is to not let the needle pass 9.00 o'clock or keep it at around 7 or 8 at the most.

 

Couldn't one just install a different thermo sensor/switch that kicks on at a lower temperature?

 

For 99% of 993 owners, hypochondriasm...

 

Wouldn't that be 99.3% :-)

 

Hey, I resemble that remark

It's often funny, I think, that these marvelous cars that we love to speak so highly of, that we continue to "tinker" with them in the quest of "improving" them ...which inherently implies that there was something sub-standard about them.

C'mon, it's funny lots of the time! So with the oil temp, sure Porsche designed the thermostat at the fan to switch on the low-speed circuit at just about 9:00. And sure the same gizmo was designed by Herr Porsche to click into high speed at above that to wick away heat and keep it from approaching the red zone. But are WE ok with that? Heck no! We choose to listen to the gurus that tear open 911 engines for a living as they warn us of the perils of high operating temps. THAT is why, for this "oil temperature" issue anyway, we all parrot "8:00 ...no more than 210 degrees..." and the like. I'm not being cynical, mind you. I just find it funny at times, especially given Porsche's "racing heritage" and "over-engineered mechanicals," not to mention the cost of admission. So do I like my oil at 210 better than at 248? You betcha! Why??? 'Cause I've been told that it's better. So there

Edward

 

Another reason for the fan switch:

in the pits or at an autocross, when there is little or no airflow over the cooler, switching on the fan will keep the oil significantly cooler.

 

I drive my 993 as a daily driver on the Los Angeles Freeways. In 90 degree weather in stop and go traffic I can hit the override switch and keep the oil cool; just below the 8:00 position.. Otherwise it would stay at the 10:00 position. I can't tell you if I am saving the engine but it makes me feel much better. It's all about peace of mind.

 

One missed point that was covered in an earlier thread on this topic is that most of the temp senders for the "Low" fan speed crap out after a few years, mine did.. you can test it (search for the thread..) while it's not the most expensive part, it's really hard to change.. Installing the switch gives you the opportunity to switch the fan on while in traffic when the (broken) low speed temp switch should have done the job..

COleman-

 

On this DIY, is disconnecting the battery an alternative to pulling the ccu out and disconnecting the wiring harness from the back? Would this accomplish the same thing? I can find the green and black wire behind the dash easy enough.

Stupid idea?

I appreciate any thoughts or comments you have...
chuck

 

you have to remove the CCU in order to acces the wire.. It takes 4 nails, or 4 small phillips inserted in the holes in the front and a slight tug.. it's actually harder to remove to power to the battery!

Coleman.

 

Thanks Mr. Coleman. I think I may be to access the wire-I found a bundle behind the dash that come out of the CCU and there is a green and black wire. But it sounds as if the CCU is relatively easy to pull through the dash. I was just afraid, that with my luck, I'd break a $900 part.

Thanks again. I am getting awful close to doing this. If the kids would cut down on baseball practice and games, I might be able to find some time to get this done.

Take care,
chuck

 

i did this diy last week. you can get the tools to remove the ccu from Kragen for like $5. why take a chance? pop in the tools and reach underneath and push the ccu out. then you can remove the connector and positively i.d. the correct wire. though it's unlikely there is more than one green and black wire it would be a shame to cut the wrong wire. i pushed the connector back through and down and worked on the splice from below.

the whole procedure took me 1 and a half hours including drilling the hole for the switch. you'll need a 3/4 inch drill bit for this particular switch which i bought at radio shack. don't forget to get some connectors for the new wires to the switch.

i just drove to vegas and back through Death Valley. whenever i was going to start driving hard i'd flip the switch first. anytime i saw the needle start to climb above the 8:00 line i'd hit it the switch and keep the temp in check. definitely "peace of mind". the whole time i was running my a.c. on full and never saw the temp rise above the 9:00 position.

 

very clean install

 

Indeed, a nice clean spot to mount the switch. I put mine in the same location, but found a smaller, rectangular black plastic rocker switch that fit nicely within the rectangular "blank." But by far the best installation is in the center console with the sunroof, etc. switches. Now that's nice! Do a search; it was just a few days ago, I think ...or maybe a week? Looked truly OEM.

Edward