Hey guys. My 87 S4's temp rises to hot (red) when I'm stuck in traffic. When I'm rolling its fine. It even goes back to cool as soon as I begin movin. I've changed the termostat. Fluid changed but couldn't get block plugs out to fully drain. Any help appreciated

 

did you change the rear seal in the thermostat housing?
are both of the fans working
how old is the water pump?
what type of coolant are you using,
and whats the mix %

 

Symptoms point to airflow. Start with the fans.

 

WP is new: < 2 months, changed all seals using Dewayne's oil filler neck instructions < year ago. Fans do seem to be louder than before. (Before TB/WP job). While sitting it cycles on/off. Blows for 30 seconds off for 30

 

One or both fans? Have you checked the flaps?

 

Chances are the final stage module is bad and only one fan is working. The reason it is lounder is that one fan quits and the other runs in high speed to compensate. Mine worked for a little while last summer after a cleanup of the module and then quit again soon after. I am just avoiding driving on hot days and I avoid traffic for now. Easy to do where I live. There was a thread where someone was building a new FS module replacement but there has not been a progress update for some time now.

 

Is final stage module hard to get to? Expensive?

 

That was J. Liedel out of Texas. We haven't had an update for a while.

 

Very easy to get to. It's on the ledge in front of the rad.
Check your fan operation first though. They should work as a pair.
Also check the fuses and connectors before you mess with the amp.
If you do a search on here, there's a number of ways of dealing with an issue if that is indeed the problem though.

 

Come to think of it....could be a fan motor too. I've had one give up the ghost....

 

I just went through the process of determining why 1 fan was operating and the other not. First check fuses 28 and 29. There is no fuse for the Control module you mentioned. If the Fan Control Module is out generally one fan will run like crazy or both will be our completely. This can be checked by removing the Final Stages Fan Module located in the left front corner as you stand looking at your car. It's about 3.5 in by 5 in with ribs. You can remove this module and open the back panel. Once you have access check to see if any of the original solder joints are cooked. If they appear in tact you can also check the amps coming from the non working fan. They should register somewhere between 13 to 17 amps or so. I have found through recent experience that the FSCM can be repaired but they can be found for a fair price used. New one's are extremely high.

Let me know if I can be of any service

Hope this helps.

 

Thanks for the knowledge. I saw you car at Wikki's place a couple of weeks ago. He charged my freon for me. That is one sharp car. I'm gonna check out my car now. Will let you know if further help is needed. Thanks for all the help guys!

 

Does the back just pry off? Will I damage anything?

 

Yes you can pry off the back to check. There is a gasket which will already be cracked and dry. If you discover that the FSCM is the issue. I have a couple places that may have them in stock "used" but with Warranty.

What in the world were you doing way over here at Wickie's? I would love to here about the connection. He's not really even a 928 guy. PM sent.

 

I have had a very hard time, 2-3 times, getting all the air out of the system. I had to burp, refill and burp again. My method is: let the car get hot, turn the heat on inside, open the expansion tank cap and squeeze the top hose repeatedly. Use gloves, it is hot. Top it off, close the cap and drive. Repeat as necessary.

Definitely check the fans are spinning and louvers are opening first.