sTyleR

Is the cooling fan supposed to come on in split intervals or simply run without stopping, before an adequate engine temperature is reached?

Grandpa#3

Hello Styler, Check out the link below for Cooling Fan Operation.

http://www.clarks-garage.com/shop-manual/cool-01.htm

Cheers,
Larry

sTyleR

Thanks for the reply. That's great information, but I am still uncertain whether the fast fan supposed to come on in split intervals (about four seconds between coming of, for about a minute total in time) or simply run without stopping (for the same minute in time), until an adequate engine temperature is reached.

Mine comes on in intervals as priory described, but I don't think that's normal.

marcoturbo

Do you run A/C when your fans come on in intervals ? If so, that's normal

sTyleR

It will run in the said intervals, regardless of whether the A/C is on or not.

smokin_944

Why do you keep saying fan? It will run??? On later cars, once the primary temperature point or trigger point of the thermal switch is reached, both fans should run at slow speed. Both. There is no interval of any kind. Once/if the high temperature point is reached BOTH fans should run at high speed. On later cars my understanding is that if you turn on the A/C both fans will run at high speed regardless of the actual coolant temperature.

sTyleR

Okay, here's a video.

http://s922.photobucket.com/albums/a...0910001636.mp4

You can hear the intervals between the fast speed fans coming on, while the low speed fans run in-between. This video was taken when the car was hot, right after I turned it off in which the fans remained on for about a minute.

smokin_944

You have me stumped. AFAIK when the key is in the off position, on late 944s, the fans only operate at slow speed. I've checked with Clark's and my buddy The German (Autohaus Porsche) and they say it shouldn't cycle between slow and high speed with the key in the off position. sTyleR, you are going to have to troubleshoot the cooling system on your S2. Read up on the procedure on Clark's and take it from there. Good luck and keep us posted.

ChrisJ951

Mine stay on high speed for about a minute until the car cools to the temp when they turn off. No fast then slow speeds like yours.

sTyleR

That's what I was thinking it should be doing. A while ago my cooling fan relay went out (fans wouldn't turn off), so I had borrowed a spare relay from an acquaintance. As I recall it, the fans would stay on high speed, as you describe, while using his relay. I eventually had to return his relay and ended up buying a couple of spare relays of my own, out of parts cars. I've found that the fan will now go between high speed and low speed as shown, and that happens with both relays.

I'll trouble shoot it. But based on the above, would it be safe to assume that I've just run across a couple of bad relays?

smokin_944

For late cars "The fans will operate is slow speed regardless of ignition switch position. However, fast speed operation is only available with the ignition switch on." (quoted from Clark's garage). I cannot attest to this myself but that is what it says.

944meister

styler, i have the same problem on my car and i will be fixing it this weekend. behind the battery under the black plastic cover there will be 2 big transisters, there will be 2 wires going to each, check the connections. you will probably need to replace the wiring all together as with my car the wires are very old and corroded looking and are obviously not getting a good connection. there was a thread on this that i found a while back but i couldnt find it, good luck.

smokin_944

944meister, I'm guessing you mean resistors, right? The two hockey puck looking things that permit the slow speed function of 85.5 and later cars... That is an excellent point! They could definitely mess things up. Good call.

944meister

resistor transistor same thing

smokin_944

Not quite,lol...