malakis48

I have a 2000 Boxter S, and the engine cooling exhaust fans both stopped working about a week apart. How much or how long can the car be driven before the fans are repaired? Should it be driven at all without the fans working??

Macster

If by engine cooling exhaust fans you are referring to the radiator fans if these do not work you should not drive the car at all. While the radiators might receive sufficient air flow with the car moving at some speed if you have to stop at a light or even slow down, with the fans not running the engine coolant temp will almost certainly rise to dangerous levels.

If you think you can circumvent this by shutting off the engine what happens is the heat load the engine has built up from running raises the coolant temp and pressure to higher than normal levels so the engine restarts with these at high and probably unacceptable levels.

(Under normal circumstances when you stop at a light of course the engine is idling and this pumps coolant through the engine too carry this heat load away. If during this the coolant temp rises too high (and in warmer climes it will) the fans come on (if they are not on already) and this removes the heat load the coolant has picked up from the engine.)

Get the car to a qualified repair shop and have the fans fixed. For both to fail at the same time is a bit odd in my experience. If one fails often it is the resistor.

A shop equipped with the proper diagnostic equipment (PST2/PIWIS) can control the fans individually to verify they work at low and high speed and if they don't then can perform simple tests to determine the cause of the problem.

Sincerely,

Macster.

Byprodriver

Heads crack quickly when these engines get too hot!

jittsl

My spec Boxster race car doesn't even have radiator fans so you can drive without them but why would you? If you get stuck in traffic you will certainly overheat the car. Porsche definitely put them there for a reason.

Ps if you want a good deal on a pair of fans let me know. I think I still have mine from when I stripped the car.

malakis48

Thanks to Macster,ByProdriver,jittsl.............since I posted question, I took car to a local shop that works on Porsche. The tech used a hair dryer to test the fans/motor and said it was fine. He said it has not been hot enough for them to turn on. I find that hard to believe, since I live near an interstate and drive it with regularity. I'm still looking for someone but not sure where to go besides a dealer.

Macster

Sure, depending upon the climate and how you drive the fans may not come on that often, but I too find it a little hard to believe, unless it has been very very mild (cool) where you are, that the fans do not come on.

Furthermore, if the car has A/C when you turn on the A/C both fans should come on at least at low speed. (High speed under some high demand A/C conditions.)

On the freeway with no stop/go or slow/go driving the fans may not come on because with the car moving the air flow is sufficient to keep the coolant temp below 212F at which point the fans should come on low speed. They are switched off when the coolant temp drops to 205F.

Even when I pull off teh freeway and drive on surface streets even pull into a drivethrough restaurant drive and wait with the engine idling it can take a few minutes for the coolant temp to climb high enough to turn on the fans.

Anyhow, to purposely get the fans to come on I drive my car long enough the coolant temp gage needle has been at or around (above) the '180' mark for 10 or more minutes. From my monitoring the coolant temp I know the engine is fully up to temperature.

Then I purposely drive the car in city traffic -- well on city streets anyway -- wtih slow speed driving, lots of stops, accelerations (just from a stop to 30mph or 35mph whatever the limit is), and idling at lights.

In a pinch I'll pull into my parking space and raise the engine rpms to a fast idle, call it betweem 1500 to 2K rpms. I hold the rpms there until I feel/hear the fans come on.

At this time if you want confirmation the fans are working and working equally well you can get out of the car and put your hand in front of each radiator air intake and feel the inrushing air and then put your hand under the car near the air exhaust -- just ahead of the front wheel well -- and feel the hot air being expelled by the radiator fan blades. Do not put your hands in any openings!

I'd do the above just for my own peace of mind that the entire circuit that controls those fans is working properly and that not only do the fans come on they both move about the same amount of air and the air temp is about the same to ensure both radiators are working about the same.

Sincerely,

Macster.