Hi,

Car is a 996 (1999 C2 cab ) and it has come to my attention that the car is overheating slowly.

Let says it's 85 outside, if I get stuck in a bad traffic, moving not faster than 1 mph, my car will be considered "overheating" within 20-30 minutes of doing stop and go.. Sometime, when parked, I can smell a very very very small prestone smell, but none of it dropped on the floor, no smoke either. Fluid level is topped. If I put the heater to "max", it will not really solve the problem, except that It will start to "overheat" in 45-60 minutes...

Car has 50k miles.

Thanks

 

OK, a few things could be happening....

#1 your fans could have a problem, there is a resistor for each fan that could go and make the fans not work. There should If I recall be two speeds for the fan. Don't run the A/C when you do this check. Turn it off.

#2 the most likley situation is that you have leaves and junk stuck inbetween the A/C condensor and the radiators. Remove your front bumper and clean it out... Since your car is a 99 you can use the boxster instructions here...

Accessing the Radiators

#3 and finally the 3rd common thing is you have air in the lines.... You need to "burp" the system. But I would check #1 and #2 first. There is a bleeder on the coolant tank. Most people open the bleeder and drive around for a day or two, adding coolant if needed then close the bleeder and you should be ok.

But 1st check #1 and #2. If they are OK and #3 doesn't work bring the car to a dealer or someone who can run some diagnostics.

 

Also, normally not necessary, but I personally did a coolant flush on my 99. There are two mods regarding this. There is the fan switch mod, Porsches are designed to turn on the fans later in the game, this switch gives you the option to precede the regular. Also there is a mod for a third radiator, similar to that of a GT3.

 

There are a couple of things that you could do here

-1st(as mentioned above),access the radiators and thoroughly clean them out

-2nd change the coolant,Porsche says it's 'lifetime',it's not,it's Dex-Cool,which is 5 years/50,000 miles

-Install the gt3 radiator kit

Good luck.

 

Do you have a link or more info on this mod?

 

What do you mean by "overheating"? What is the coolant temperature based on the reading from the climate control or scanner?

 

Hi,

My car is a canadian car and temp reading when "overheated" if over 100deg celcius. There is a mark between 80 and 120deg, and I presume that the middle between is 100.. At 120deg celcius, you are in the red portion and the light will come on.

Thanks

 

Porsche designed the engine to run at approximately 90C when it is receiving full airflow past the radiators. However, in the realworld, the design of the cooling system and front bumper does not allow the engine to get enough air to keep it close to this temperature when driving around town. In addition, the flow of the water pump not sufficient. This has been corrected by Porsche in later models. Therefore, the engine regularly will reach tempertures of 105+.

If you simply use the car for driving around town, those coolant temps will not be a problem. If you regularly get on the engine or track the car, the heat is robbing you of power as well as contributing to unecessary engine wear.

If you want to maintain coolant temps closer to the range intended by Porsche at all times, you can complete my simple fan mod. This will drop your coolant temps by 10%+.

Radiator Fan and Engine Compartment Fan Switch Mod


The 3.4 996 runs extremely hot when driving around town in temperatures higher than 75 degrees. This mod is a way to reduce coolant temps back to a safer level, helping to reduce oil temps and improving performance.

The mod consists of installing a switch that will allow you to turn on the high speed radiator fans at any time, while maintaining the automatic operation of the fans. We do the same for the engine compartment fan.

Radiator Fans

Connect a wire to the ground of the 2 high speed fan relays located on the relay carrier located in the driver’s side foot well. The relays are #20 and #22. Feed this wire to where your switch will be located. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and then connect the other end of this wire to a chassis ground point.

With key on, this switch will now immediately turn on both radiator fans providing maximum cooling. When you turn the key off, the fans will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off.

Jim

BTW: Your gauge does not give you an accurate indictaion of what you coolant temperature is.

EDIT: I missed that you stated that the light comes on. In this case, if coolant level is fine and the system is properly bled, you may have a stuck thermostat (easily replaced) or a bad waterpump (worn). Either way, what I stated above still applies. Be sure both fans are running full speed when you are running at temps above 105C,

 

I already done mode for Front Fans . How i can do mode for Engine Compartment Fan Switch Mod ?
Thank you
Vadim

 

Engine Compartment Fan

Connect a wire to the ground of the relay located in the relay carrier behind the passenger seat, driver’s side. Relay #8. . Feed this wire to where your switch will be located. I simply fed the wire along the driver’s side of the car and under the door sill. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and connect the other end of this wire to a chassis ground point.

With key on, this switch will now immediately turn on the fan drawing air into the engine compartment. When you turn the key off, the fan will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off. This mod helps keep the engine compartment much cooler when driving around town and is particularly beneficial to any engine that draws its intake air from inside the engine compartment, such as the EVO SC.


If you are adventurous, you can automate the operation of these switches so they will switch off at a specific speed, or operate when vacuum is present only, etc. You can choose any style switch you want and even use Porsche switches. I simply used 2 toggle switches that I installed in the batwing,

Jim

 

Super ! Thank you Jim ! Any photo's were i can find this relay ? Relay will be behind drivers seat ? Right ?

 

Pull up the carpet on the back shelf and the relay carrier is on the driver's side. Remove a few screws to get access under cover.

 

Thank you !!! Great information . How hard to change termostat ?

 

Not difficult. Drain some coolant from the bottom of the engine using the plug on the center back of the engine, disconnect 1 end of 2 small hoses on thermostat housing and pump, remove 4 10mm bolts and remove housing. Gasket may remain intact but I use a coating of liquid gasket when I put the housing back on. Pour drained coolant through a coffee filter and pour it back into the engine.

Thermostat is rated at 83C. Running without the thermostat on the 3.4 engine increases the coolant flow sufficient enough to further drop coolant temps at speed.

 

Thank you !