Temp Guage Warning Light Flashing...

[P1CR]

Manual says its the engine compartment blower fan.

It does not come on all the time, and resets itself when I turn the car off.

Thoughts on a DIY?

Thanks everyone!

[KarlS]

This is a common problem with the 1999 model. There is a TSB on it (I'm sure Loren can give you the number). The TSB calls for replacement of the coolant overflow tank and cap. There was a design issue with the first gen tanks that allowed the coolant to flow away from the sensor under heavy acceleration and trip the warning light. Mine used to always come on at the track but once I had the TSB done, I never had the problem again.

Karl

[Loren]

First have a look at this in the Tech Tips section...

Flashing Coolant Light -- What it means.

From TSB 8/99 1940 Coolant Expansion Tank dated 10-22-99

A new type coolant expansion tank is installed in production as of February 23, 1999 and VINs:

99 7 XS 62 5704, Coupe

99 7 XS 65 4287, Cabriolet

The new coolant expansion tank (part number, 996 106 147 55) prevents false illumination (flashing) of the coolant warning light when the volume of coolant fluctuates in the expansion tank. When replacing an engine on vehicles prior to the above VINs, the new type coolant expansion tank should also be installed. The new coolant expansion tank can also be installed (on vehicles produced prior to the above VINs) for repeated complaints of coolant light flashing when there are no indications of overheating or coolant leaks.

Note: A thorough bleeding must be performed to ensure no residual air pockets exist in the cooling system.

There have been at least 3 tank designs. The latest one is 996 106 147 56. BTW... leaking caps (and hoses) have also been a problem.

Just an FYI... The MY01 and newer cars got yet a different (larger) tank and there have been 3 of them also.

[P1CR]

Covers all Carrera, GT3, TT / GT2 and Boxster cars

Here is the long explanation from the service manual on the flashing coolant light.

"Four functions of the coolant warning light:

1. Engine coolant level too low -- light flashes slowly (0.5 Hz)

2. Engine compartment temperature too high -- light flashes slowly (0.5 Hz) (engine compartment blower might be faulty)

3. Engine coolant temperature too high -- light is lit; pointer on the right

4. Temperature sensor at water outlet faulty -- light flashes rapidly (1 Hz) ; pointer on the right

Note: The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously."

So,...How do I figure out if it's the tank?

I know, check the VIN. What if it's been replaced already? (I'm the second owner).

Is there a way i can tell if it's the engine compartment blower?

Also, what's involved with changing the tank? Bleeding the system, etc...

Thanks so much for the input guys,

[Loren]

1) Do you have any leaks? Is the the coolant level below the mark? If so, you need to find the leak first.

2) Call a dealer and ask them to check your VIN and see if the tank was replaced.

3) The engine compartment purge fan rarely comes on. Mine has only come on twice -- and I live in 90 plus degree California! Here are the conditions the fan comes on at.

Switch-on conditions for engine compartment fan (this fan pulls air into the engine compartment) The engine compartment fan is switched on when the engine compartment temperature is > 176 degrees F or the coolant temperature is > 216 degrees F. 

After-running of engine compartment fan 

If the ignition is switched off and the engine compartment temperature is more than 140 degrees F, the DME control module remains in readiness for another 20 minutes. During this time, the engine compartment temperature is retrieved every 10 seconds. If the engine compartment temperature is > 185 degrees F , the engine compartment fan is switched on for 20 seconds. If the engine compartment temperature is still > 185 degrees F after this time, the fan remains on for a further 30 seconds.

4) There is one TSB where some of the fans were wired wrong (reversed) but this was only on aerokit cars (sorry, can't remember if your car has an aerokit). But this was just a few cars and again the dealers were supposed to correct this.

5) Changing the tank just takes some time as you will need to remove a few other items (air pump, hoses, etc). You will need more Porsche coolant and bleeding the system is as simple as opening the bleed valve and then refilling when cool.

[P1CR]

I have a coolant leak.

Just noticed coolant dripping onto the driver's side exaust tip.

Running temps driving hard in a 90 degree day were still cool. So it seems to be a small leak.

Also, the light only came on yesterday (in the heat), but not on my 45 minute drive to work this morning (it's much cooler outside).

So I think htis leak is related to high temperatures.

Of course, laying under the car only taught me that its running down the inside of the bumper cover. I can't otherwise see any obvious places from which it's coming.

Anyone?

[SPR]

Hey loren do you have the write up of replacing the coolant tank then? I just took my car into the dealer for some small things and surprise they wanted 500 bucks to do it! I would appreciate it as well as the part numbers for the best and newest tank and cap that will fit in my 99 996 c2 coupe. thanks.

[Loren]

Hey loren do you have the write up of replacing the coolant tank then? I just took my car into the dealer for some small things and surprise they wanted 500 bucks to do it! I would appreciate it as well as the part numbers for the best and newest tank and cap that will fit in my 99 996 c2 coupe. thanks.

Have a look at ninerguru's DIY with pics here

996 106 147 56 is the tank that is shown for cars prior to MY01. Double check with a dealer as they have changed these 3 or 4 times and my parts list is Nov 2003.

The cap is: 996 106 447 01

[SPR]

Thanks Loren! I totally thought you had to drop the motor to replace the tank but it looks really really easy- easier than doing the third radiator for sure! I spoke to the dealer and he said that the larger tank will not fit in my year? Is the part number you listed not only the newer one but the one with the antislosh relocation? thanks again! sean

[SPR]

Hey also Loren, is the thermostat in the bleed recepticle? I was curious about the possibility of being able to put a newer thermostat in as it appears that the newer ones let the engines run cooler not so much the cooling efficiency?

[SPR]

never mind I check a pet pictorial and it showed the thermostat in a different location. oh well.

[Loren]

Thanks Loren! I totally thought you had to drop the motor to replace the tank but it looks really really easy- easier than doing the third radiator for sure! I spoke to the dealer and he said that the larger tank will not fit in my year? Is the part number you listed not only the newer one but the one with the antislosh relocation? thanks again! sean

The number I gave above is for the pre MY02 (3.4 liter) cars so it should fit fine.

[Loren]

Hey also Loren, is the thermostat in the bleed recepticle? I was curious about the possibility of being able to put a newer thermostat in as it appears that the newer ones let the engines run cooler not so much the cooling efficiency?

To my understanding the thermostat has not changed since introduction (including the 3.6 liter update).

[SPR]

cool good to know then thanks as always

[SPR]

Hey Loren thanks for the link and part numbers. I just swapped it out in about 1h. I think it is running cooler a lot also! It sits at the 8 now just a hair after the real 180 mark!