why after i drove my boxster for 30mins them tempature will at "0" of 180 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

ferrari355 · 03-08-2007, 07:26 PM

i think my car is having problem now, after i drive it for around 30mins, the tempature gauge will point at 0 of the middle 180. sometime will at the next black mark which is the one before the 250'. i checked the coolant which is ok, also if i try to turn on the heater the temp will go up a little too. i think maybe the cooling fan is no working? anybody who had same problem please help me!!

03-08-2007, 07:29 PM

Are the front radiators clear/clean?

racer_d · 03-08-2007, 08:13 PM

Quote:

Originally Posted by bmussatti

Are the front radiators clear/clean?

Excellent point. Lots of times these are neglected. Leaves and other debris will build up over time and impact the cooling effectiveness. Plus, its not so easy to notice the build-up without crawling around on the ground in front of the car.

Also check the fuses for the fans. These can fail and cause the fans not to come on.

Also, what kind of drive? 30 min stop and go city traffic at low speed? Highway cruising? High rpm track driving

?

The "zero" of the 180 is not an issue. Warm perhaps, but not a problem. When it gets closer to 230-250, then there is a definate problem.

Does turning the "heat" on full blast help reduce the temps? (it should), should you have an emergency near melt-down.

ferrari355 · 03-08-2007, 08:33 PM

Quote:

Originally Posted by racer_d

Excellent point. Lots of times these are neglected. Leaves and other debris will build up over time and impact the cooling effectiveness. Plus, its not so easy to notice the build-up without crawling around on the ground in front of the car.

Also check the fuses for the fans. These can fail and cause the fans not to come on.

Also, what kind of drive? 30 min stop and go city traffic at low speed? Highway cruising? High rpm track driving

?

The "zero" of the 180 is not an issue. Warm perhaps, but not a problem. When it gets closer to 230-250, then there is a definate problem.

Does turning the "heat" on full blast help reduce the temps? (it should), should you have an emergency near melt-down.

thanks for replying!so where is the fuse box for the fan? it is on the left driver pedals area?

ferrari355 · 03-08-2007, 08:35 PM

i was driving at city without pass 3500rpm!

MNBoxster · 03-08-2007, 09:00 PM

Hi,

To check the Fans, turn on the AC - the Fans default to ON with the AC, this will tell you if the Fans do operate, but not necessesarily whether they are Temperature responsive.

As mentioned check the fuses (C8 - Rht., C10 - Lft.) but also check the relays. The Boxster uses two-stage (speed) Cooling Fans controlled by a resistor integral to the wiring harness. The fans have a Relay for each speed (Low/High). These are #19-22 (#19 - Lft. Low, #20 - Rht. Low, #21 - Lft. High, #22 - Rht. High) in the underdash Relay tray.

But, since you also report unusual Gauge Readings, I might also suspect the Coolant Temperature Sensor. This is because it is an NTC Resistor which sends a signal to the Temperature Gauge (pins 1,3) and to the DME which it uses to energize the Cooling Fans (pins 2,4). If you have a Code Reader, download any codes you may have stored (these will not all throw a CEL). In particular, look for codes P0115, P0117, P0118. If you have a faulty Thermostat, this can also throw a P0115 code as well. Hope this helps...

Happy Motoring!... Jim'99

ferrari355 · 03-09-2007, 12:12 PM

today i turned on the ac, i only feel that the right side fan is blowing out air, the left side didnt. when the ac is on, both fans suppose on right?

MNBoxster · 03-09-2007, 01:24 PM

Quote:

Originally Posted by ferrari355

today i turned on the ac, i only feel that the right side fan is blowing out air, the left side didnt. when the ac is on, both fans suppose on right?

Hi,

Yep... both should be functioning. Check the items in my previous post. But, I also think your radiators may be in need of a good cleaning too because once the car gets to 27MPH or so, the airflow through the radiators is sufficient to keep the system cool w/o the Fans on all but the hottest days or Stop & Go traffic. Good Luck!...

Happy Motoring!... Jim'99

CJ_Boxster · 03-09-2007, 02:14 PM

Quote:

Originally Posted by ferrari355

today i turned on the ac, i only feel that the right side fan is blowing out air, the left side didnt. when the ac is on, both fans suppose on right?

When you say fans... do you mean the fans behind the radiators right? not the interior A/C fan for passengers?

ferrari355 · 03-09-2007, 04:55 PM

Quote:

Originally Posted by MNBoxster

Hi,

To check the Fans, turn on the AC - the Fans default to ON with the AC, this will tell you if the Fans do operate, but not necessesarily whether they are Temperature responsive.

As mentioned check the fuses (C8 - Rht., C10 - Lft.) but also check the relays. The Boxster uses two-stage (speed) Cooling Fans controlled by a resistor integral to the wiring harness. The fans have a Relay for each speed (Low/High). These are #19-22 (#19 - Lft. Low, #20 - Rht. Low, #21 - Lft. High, #22 - Rht. High) in the underdash Relay tray.

But, since you also report unusual Gauge Readings, I might also suspect the Coolant Temperature Sensor. This is because it is an NTC Resistor which sends a signal to the Temperature Gauge (pins 1,3) and to the DME which it uses to energize the Cooling Fans (pins 2,4). If you have a Code Reader, download any codes you may have stored (these will not all throw a CEL). In particular, look for codes P0115, P0117, P0118. If you have a faulty Thermostat, this can also throw a P0115 code as well. Hope this helps...

Happy Motoring!... Jim'99

well, today i opened the dust cover and used a battery connected to the fan directly and the fan worked. also i checked the relays, i did switch the #19 20 21 22 and still only the only right fan is working so i dont think is the reley. but when i check the fuse box i cant find where is the c8 and c10 because it only had numbers on it i cant find where is the "c" 10. so what i am thinking is the resistor for the fan, but where is that?

MNBoxster · 03-09-2007, 09:36 PM

Quote:

Originally Posted by ferrari355

well, today i opened the dust cover and used a battery connected to the fan directly and the fan worked. also i checked the relays, i did switch the #19 20 21 22 and still only the only right fan is working so i dont think is the reley. but when i check the fuse box i cant find where is the c8 and c10 because it only had numbers on it i cant find where is the "c" 10. so what i am thinking is the resistor for the fan, but where is that?

Hi,

The Ballast Resistor is in-line with the wiring harness between the two fans. It is integral to the harnes, but available as a separate part (PN# 996.616.101.00) which must be spliced into the harness. Hope this helps...

Happy Motoring!... Jim'99

ferrari355 · 03-09-2007, 09:59 PM

Quote:

Originally Posted by MNBoxster

Hi,

The Ballast Resistor is in-line with the wiring harness between the two fans. It is integral to the harnes, but available as a separate part (PN# 996.616.101.00) which must be spliced into the harness. Hope this helps...

Happy Motoring!... Jim'99

sorry that i still dont get it, is it on the back of the left fan? is that resistor for both fans? if so why there is only right fan is working now? also can i run a wire from the right fan to the left would be that easier?

MNBoxster · 03-10-2007, 09:00 AM

Quote:

Originally Posted by ferrari355

sorry that i still dont get it, is it on the back of the left fan? is that resistor for both fans? if so why there is only right fan is working now? also can i run a wire from the right fan to the left would be that easier?

Hi,

The Ballast Resistor is integral to the Fan wiring harness, just before the connector. There is one for each Fan. It reduces the voltage supply for low speed Fan operation. This resistor dissipates a great deal of heat and as a result it burns out periodically. The part # is: PN# 996.616.101.00 and it costs about $20. There is one resistor for each Fan. To replace, you must cut out the old one and splice the new one in it's place.

Two-speed fan operation? Why not forget about fixing the ballast resistor and just run the fan at high speed? Because there is a large inrush of current when going from OFF to High Speed directly and the High Speed fuse or relay may blow, leaving you with no Cooling Fan. Lastly, this is very hard on the fan bearings, shorting the life of this expensive Fan (PN# 996.624.135.00) - about $300.

The other possibility is that the Fan itself has failed and might need replacing. But, there are two things you can do. Just replace the Resistor anyway because it's most likely the issue and is a much cheaper starting point, or either swap the Fans Lft. for Rht. to see if the other Fan indeed operates. You could also fashion a jumper harness and leave the Fans in place accomplishing the same thing. Hope this helps...

Happy Motoring!... Jim'99

ferrari355 · 03-10-2007, 11:06 PM

thanks for you early replys! MNBoxster
have another question, is there any way i can bypass the resistor?

ferrari355 · 03-10-2007, 11:08 PM

also i did hook up a battery to the fan directly, the fan worked. i also found the c10 fuse but it was blown, i put a good fuse on c10 but the fan is still not working and the fuse wont blow again.