dammad

As you may see from my past posts, I had a overheating scenario this weekend. I'm trying to track it down. By car has a new coolant tank a few months ago (latest style from Porsche), however I'm thinking that the coolant tank cap or value may be leaking.

Could it be that a new tank doesn't come with new cap and bleed value?

No steering pumps or other things up in front of the cabin yet behind the wheels? AC or power steering?

Car went okay today avoiding traffic. Trying to nurse it home tomorrow then I can get more info.

Ac hack is holding down upvent and recirculate at the same time. sixth number is an approx coolant temp.

Thanks for the ideas. The squeal comes even when the fans are off so don't think it is a fan bearing or squealing ballast.

Yes definitely from the front, loudness at the rear of the wheel arches. Water pump is about 15000 old so i assume okay.

Strange huh?

Had a pleasant drive to Yosemite this morning until I hit the hills. No sooner and I see the temp guage going high. Switched on the 6c Ac hack (no tester handy) and watched it go up to 111c. Both fans working,ac on and 100f outside. Stopped, let it cool and continued up the hill. This time it hit 113f before I could stop (AC on).

I'm at the hotel now and noticed that there is a loud squeal noise at the front (no particular side). Let it cool again and started with Ac off. No noise initially but after a minute or two the squeal came on again. A few

minutes later the squeal reduced and then returned louder.

During this time I turned the AC on to see if it helped, but no change to the squeal. Fans both came on and held the temp steady.

Turned off the AC and the temp went up but returned down again after the fans kicked in.

BTW I have a tiptrinic so believe there is a third radiator up there. Is there a third fan?

Given the fans seem okay, any ideas why it got soo hot or it making the strange noise?

Need to drive into yosemite valley so need to determine if it is okay? Wife will not be happy to breakdown there.

Renntech please help. I have a slate grey metallic 996 cab, and i keep it clean as possible, and covered 99% of the time in LA. I noticed that my decklid is losing its shine very quickly and becoming almost dull in apperance. Has any one else heard of this?...It's on on the deckild, and the car does not run hot. Thanks for your advice.

I have slate grey too, beautiful color. :) I'd suspect the cover you use. Do you leave it on in direct sunlight? During/after rainstorms? Is it fading on your front hood or rear engine cover? It could be deteriorating clearcoat on a paint repair. The factory clearcoat is pretty robust unless you leave it sitting in the desert sun for months at a time or expose it to solvents or other abrasives.

It's quite possible that a good polish can fix this problem. Go to a local auto shop and pick up some Meguiar's fine cut cleaner #2 or 3M rubbing compound (both are readily available polishes and have a medium cut), along with some microfiber applicator pads and microfiber towel. Wash the car, then pick a small section (2" or so) of the dull paint and with a nickel-sized dab on the microfiber applicator, apply the compound in a firm , even swirling motion for about 10 seconds and then lift. If your applicator has grey paint on it stop immediately, that means the dullness is caused by your clearcoat wearing off. If not, continue applying until the compound has dried to a haze, then remove the residue with a microfiber towel.

If you like what you see on your test spot, do the rest of the lid. Post some pictures for us so we can see the damage.

Mark

Mark - Thanks mark take a look at the damage:

Dammad - Does yours resemble this?

Loren heres a pic of the damage

Yes, exactly like that.. But mine is the spoiler itself, not the lid part.

I have the very same problem on my 1999 996 Tip (Arctic silver). I'm the third owner and keep is about 50% in sun and 50% out of sun. Regularly cleaning.

I have tried various polishes on it, but it looks like the paint itself is fried because it has a line-y appearance.

My car overheated at one point 2 years ago when the water pump broke. Not enough to damage anything, but resulted in lots of coolant steam out the back. Alas at the time I was more concerned about the motor, so forgot to wash down the back. So perhaps it can be caused by coolant stream condensing on the lid, since the coolant would eat into the paint.

Dammad.

I do not know. As soon as I repaired the fans I went back to the regular screen on my ac panel.

I will have to check. I have put the car up for the week so this weekend I will get it back out for a PCA drive. If you are close to OKC come on with us. Saturday Morning we meet up at 9 or so.

Alas I'm in California. But let me know what you find out at the weekend.

Appreciated.

Well I called my dealer, Bob Moore Porsche and they had the part! I went up and picked it up and installed it. Works like a charm. The low speed fan now comes on when I turn on the AC.

Thanks for the direction and Thank You Bob Moore Porsche for having the part in stock and taking care of me!

Install notes:

I pulled the headlight out and then the plastic wheel well. This gave me enough room to run jumper wires and to cut and install the new ballast. Cut a few wires, a little solder, tape everything up, tie off the wires, replace the liners and time for a test ride. She runs nice and cool now.

Great. Just out of interest, at what temperature in practice (according to the AC 6c display) do the low speeds now getted turned on (with the AC off)?

I have a fan not coming on now.....So if I get a tester to check the ballast, what readings should I get. (volt meter tester)

I checked the fuses, switched the relays around, turned the fan blades, the driver side was very easy to turn (the one not working) and the passenger side was just a little harder to turn with some magnetic resistance if I am guessing.

Well, I just did the AC panel adjustment and got the car to temp.

With the AC on the passenger side fan comes on high. The temp stays under 98. With the AC off the temp will rise and at 103 the passenger side fan comes on high.

So, I have no low speed on either side and the high speed is not working on the driver side fan. It looks like the drivers side ballast was replaced and the connections are tight.

I am thinking I will pull the inner finder liner and try to jump the motor as above..

1999 C2 with tip. 120,000 miles.

I have a similar situation on my 1999 C2. I found that the AC hack temp isn't very accurate and the OBDII showed lower figures. I also found that when the fans came on at 103C it was the low speed fan not the high speed (they are much louder). So don't assume it is the high speed fans coming on.

To easily hear the high speed fans, just pull out the low speed fan relays (drivers footwell). The high speed fans will cycle on/off.

some information based on my investigations for future members with overheating:

(1) AC coolant temp hack (6c) isn't very representative of current coolant temperature. When comparing with the OBD2 figures, the AC figure is a running average and 1-2C higher than OBD2 coolant temp (PID 0x05).

(2) If you remove the relays for the low speed fans (drivers footwell), the high speed fans will cycle on/off with a 2-3 minute interval from cold. This is a real easy way to see if the high speed fans and how noisy they are.

(3) Slight pressure leaks in the coolant system can allow the system to not fully pressurize. If things are running hot, clean the rads and check for slight leaks on the coolant (for example the tanks are prone to go).

(4) On my 99 according to the OBD2 numbers, the low speed fans come on at 100C and turn off again at 96C. I assume the DME has a more direct sensor value, so 100C on the OBD2 might be 96.75C to the DME.

Thx. didn't realise they were in that fusebox.

Okay I've read that the relays for the fans (cooling) are behind the driver's seat under the shelf carpet. I've peek under a bunch of carpet back there and don't find anything.

I've a 99 C2 Cab.

which is it:

1) under the floor carpet behind the seat

2) under the seat itself

3) under the rear seat footwell wall carpet (faces driver's seat)

3) under the rear seat's themselves?

I found the relay in the drivers footwell fuse box (underneath), but not this 2nd relay box.

Has anyone used Klasse All-in-one Polish on a car with ah 3M Clear Bra?

I've read a review on Amazon that seems to imply Klasse will ruin the clear plastic. But I find this difficult to believe (after all they are both Arcylic).

I used Klasse AIO on a 3M clear bra on my 2004 G35c for about 5 years. I did not notice any problems when applying it not afterwards. HTH.

Thanks.

Has anyone used Klasse All-in-one Polish on a car with ah 3M Clear Bra?

I've read a review on Amazon that seems to imply Klasse will ruin the clear plastic. But I find this difficult to believe (after all they are both Arcylic).

How do you know the AC Hack temperatures are what the DME is seeing?

You need to look at what the DME is seeing with a PST2 or PIWIS.

Yes, I don't know what the DME is seeing.. May have to take it to the dealer to see.

Just to be clear, I'm trying to work out if there is more than one sensor that the various parts of the car use for 'coolant temperature'.

I've got the wiring diagram from the workshop manual, but can't make head-nor-tail of the various connections from page to page.

I've been trying to track down why my '99 996 cab tip runs hot (99-104C according the AC temp hack). Fans run on low speed when the AC is on, but refuse to turn on when the AC is off. Yet, the AC temp hack says the coolant temp is 99C+.

However, the manual says:

"Electric fan, speed 1

(Ground to DME control unit, terminal 35)

Coolant temperature higher than 96.75°C or air conditioning switched on.

Electric fan, speed 2

(Ground to DME control unit, terminal 36)

Coolant temperature > 102°C or air-conditioning fluid pressure switch closed (coolant pressure > 16 bar)."

So what gives? If the AC thinks the coolant is 99C+ and the AC is off shouldn't the fans come on. After all they definitely work with the AC switch depressed?

Could it be that the AC and DME get coolant temperature from different sensors?

First of all, your engine never ran at 80C. If it had, your thermostat would have remained closed. The high speed radiator fans do not come on just because the A/c is on. I have heard otherwise on this board but on the more than 35 996's I have tested, NONE of them come on high just because the A/C is on. High speed fan operation is determined by pressure in the A/C and/or coolant temperature.

The targeted coolant temperature for the 996 is 90C and in reality, it will run slightly above that at highway speeds. Slower, around town driving may raise the temperature to as high as 105 -110C unless your fans are running on high.

Apart from something broken or jammed, why won't the fans run on high with the car above 105C? What temperature are the fans supposed to switch to high speed?

There are a bunch of threads on here related to fans not running at high/low speed that cause some cars to go up to the mid-to-high 100's celcius. Might want to check if your fans are running.

My 1999 996 rans around 94C normal, but has recently edged up to 100+C, so I'm investigating the same issue myself.

What temperature is a 3.4 996 supposed to run at? Mine says 101C. Seems reasonable (just around boiling).

I have a similar need. Can you PM me the info too?

Alan.

I need to replace the pulleys on my '99 996. Not sure how easy it is to do DIY, so wanted to know what the book-time (recommended time by Porsche for the change) was to see how expensive it might be.

I've had this kind of information in the service manuals for other vehicles I have owned, but can't seem to find this for the 996? Very useful to keep independent repair shops honest.

Decided that I might be able to work out the problem just by taking off the airbox and listening (down a pipe) to localize. Seemed a little less ambitious.

It seems that the noise is coming from the top roller on the serpentine belt by the alternator. Are these known to go bad? I assume they have some bearings inside. Is there anything near that roller that it could be instead?

Thanks.. Didn't know that was possible.

I let it to cool down and started again. This time the clunk, clunk is more of a whurr, swish, swish noise now with the same kind of speed. So it sounds like an alternator or AC pump (water pump was changed at 90k).

I noticed that my 99 996 cab has seem to become a little noisier to drive recently. More 'gruff' in engine note, but otherwise runs fine.

Out of curiosity, I parked and left it ticking over to check out the engine. On opening the engine compartment, I noticed immediately that there was a noticeable (but not from inside the car) 'clunk, clunk, clunk' noise coming from the top center of the engine with a period of about 2 secs for 3-4 clunks. I turned off the AC, fan, etc. to help rule out those, but it remained. Alas I was on my own so there was no way to increase the RPM while listening but will try that when I get home.

I've also noticed that the AC causes a bit of noise when on (audible from inside the car after running it for a while). Do you think the noise might be the bearing going on the AC or something worse (blow engine)?

Given the speed/idle it seems like it could be the tappet on one of the cylinders, but why would that 'clunk' rather than tap as normal?

The car has 105k miles on it and runs well otherwise. New mobil 1 0w40 about 1000 miles ago. O2/MAt done about 10000miles ago. No CELs or anything.

??

Dammad.

I called emailed sunset to get a quote on a 3 button remote and was told that a 3 button remote won't work on a car 99-01 (1 button). Has anyone tried this on a 99-01 car (preferably a cab) that can confirm??