SubzeroX

Its the same for me WalterRohrl, starts when i come to a halt, goes off after 5 seconds.

WalterRohrl

Ok, mine's an '02. I am fairly certain it is not the SAI pump. But it only does it once a day as far as I can tell but after driving for a bit and in my case the third stop. It COULD be that that is when the T-stat is fully open, that's about the distance it takes for the water temp to be warmed up if I think about it. That would make sense as to why it only does it once. My coolant level is fine, BTW. I don't usually have two completely cold starts in a day as I work from home. Take the kids to school, run errands, come back and do various things without letting the car sit all day long like if I worked a normal office job.

Thundertub

SubZeroX,
Please listen to those who have suggested that you use distilled water and not any other brand of antifreeze to top off your coolant. We have had a jillion threads on this over the years and the conscensus from the truly knowlegeable is that the Porsche antifreeze is a unique chemical mixture and does "work or play well with others" when off-the-shelf antifreeze is added to the system.

Yes, it could be as simple and cheap as just needing a new coolant cap. They do fail. You will need the Porsche-specific cap, and yes, the serial number should end in .04 to be the latest update.

For anything else, go to a Porsche certified mechanic for trouble shooting.

The description of the fan motor running sounds very much like the SAI motor. It runs randomly when the engine is either cold or very hot. That is the motor still running when you walk away from the car after being very hot.

My temp gauge also reads on the left side of the 0 at this time of year. That is not a bad thing.

SubzeroX

yea i added distilled water.. thanks guys!

Macster

You sure it is not the secondary air injection pump? It can come on after cold start if the DME determines the converters need extra air the air being injected into the converters directly.

I've never heard it come on but it could be with your type of driving early on a cold morning... is your route downhill?

WalterRohrl

Hi Macster,
My route is pretty flat with a slight downhill (gentle grade) just before the third light at which I hear the fan come on. Similar to the slight downgrades you get out there in Livermore, nothing "steep" at all. At the second light I make a right turn, then on the gas fairly hard up to about 50mph, then I let up as I pass the police station (heh heh), then I kind of coast on light to no throttle to the third light down the slight grade.
My SAI pump makes a quite harsh sound, almost a high-pitched metallic scraping noise (more of a "zinging" noise like a rotary saw blade), the noise I hear at the light is very different, more like what you'd expect a cooling fan to sound like. I suppose it could be a pump but only if there are two components to the SAI and only one of them runs at this time as opposed to the two at startup. I don't think this is the case having dealt with an SAI on a Saab previously, so I believe I understand what/how they do in general. The mornings ARE cold, often in the 20's out here since I've noticed it. (same as the OP, I think)
I don't consider any of this a problem, I was only trying to point out that the OP very likely could have two different noises as others suggested the SAI for him and based on my experience I did not think his noise was the SAI pump (only due to the fact that I can detect two very different noises (SAI and then the later mystery noise)). Not sure if that made sense but the OP did respond and said that his noise was different from the startup SAI noise as well.
I'll keep listening and will report back if I can think of anything else...

Pac996

There is a fan on the engine lid compartment for cooling the engine compartment. I'd think that would come on only when the engine is hotter that the front fans can take care of.

fpb111

It would be an interesting experiment to unplug the lid cooling fan to see if that is the 2nd fan noise at the 3rd stop. Odd that it would come on after such a short drive in cool weather.

For the OP. My expansion tank likes to stay ~1/8" below the Min line when cold. I can top it up to Min, when cold, every week and drive myself crazy obsessing or just let it sit at the 1/8" low for months. It shows Max when hot.

street rod

Walter you may know this but the rotary saw blade sound is not normal. This is your SAI pump starting to wear out. They normally sound more like a vacuum cleaner. If you can stand the sound it won't hurt anything however and you can use it until the pump eventually fails. Mine was doing the same thing so I replaced it with a $150 used one off Ebay. Takes about 20 minutes to do the job.

WalterRohrl

[QUOTE=fpb111;10117985]It would be an interesting experiment to unplug the lid cooling fan to see if that is the 2nd fan noise at the 3rd stop. Odd that it would come on after such a short drive in cool weather.

I'll try that one day next week when I start taking the little guy to preschool again after concentrating on the noise the first few days. And I will report back...

Thanks!

WalterRohrl

Thanks for the info, I didn't know for sure but suspected it, the noise is a bit extreme to me. I'll start looking around for a new one. Weirdly enough I got a check engine light today after about a mile or two of driving. The SAI did come on but maybe it is really close to dead. Code reader is ordered and on the way, will report back with the code. Car drives just fine (as it would with a dead SAI) but the code could be many other things of course. I won't replace anything until I know for sure which code...

fpb111

Some folks have "rebuilt" the $AI. As I recall it was mostly cleaning the impeller(s) and light lube of other parts.
Or if that doesn't work pay $1800 for new Porsche box with $300 Bosch part in it (or just buy the Bosch Part in an ugly Bosch box)
http://www.autoatlanta.com/results.p...605%20104%2000