Morning Paul,

Each fan has it's own fuse, check to see if one is busted. I had his problem too (just one fan running), turned out a previous owner messed with the wiring and connected one fan wrong.

Off to work!

 

Hi,
just took her for a ride.
It seems the temp is slightly lower.
Normal usage = around 90 degrees
Hard driving = +/- 94 degrees.

These temps are a bit lower than I was used to see BUT....

When I came home the blades were close again. I think the wind has shut them closed again somewere BUT.....

When I did a closer inspection I saw a little rod (not sure if this is the right description) about 25 centimeters long. When ik pull it the blades close and when I pus it they open (or the other way around). I think this rod should be connected to a motor so I think my temp. problems are gone when this is fixed .

Thanks a LOT!

 

Hi,
is this fuse situated in the engine compartment or where all fuses are located under the dash ?

All fuses under the dash seem OK. If checked them earlier....

Thanks,
Paul

 

Paul,

The fan fuses are located in slots # 29 & #30 (30 amp fuses) in the CE panel behind the wooden false floor in the passengers footwell. If the fan fuse is blown then replace it and see whether you get both fans operating at full speed via A/C switch being depressed and ignition on with engine running.

On the back of this wooden panel there should be a Fuse and Relay Chart. If it is not there you can down load a Fuse and Relay Chart from 928 Specalists at www.928GT.com by follow ing the links.

You mentioned that the crank arm is disconnected from the flap adjusting motor. To check whether the adjusting motor is operating, note the position of the crank with the ignition off. Now turn the ignition on, 1st it should go to 30% opening and the push the A/C switch on and note the position of the crank to see whether it has moved to 100% open(not sure if the engine need to be running at this time as A/C has a pressure switch in the circuit that will cut out the the clutch on the A/C compressor). Take care as when you are doing these test there will be a heavy drain on your battery, so I may be better to have the engine running.

If flap adjusting motor crank has not moved check fuse # 18 which is a 7.5 amp fuse and is titled "Cooling -Air Flap Adjustment". If the fuse is blown then replace it and check to see whether the crank now moves from the park position to fully open position, flaps at 100% open.

If it moves then reconnect the crank arm to the crank. When this is done you can check to see whether the flaps fully open when the engine is running and A/C is on.

If the adjusting motor is not working, I would suggest that you pull the fuse 18 and wind the flaps open manually, by removing the rubber boot over the motor which is located in front of the A/C condenser at the top and turn the **** on top of the motor. In this position you can safely drive the car and get the correct cooling, however, the engine will take longer to reach operating temperature, so don't flog the motor until it is warm.

If both fans are working at full speed with A/C on then there is no further problems with the fans at this juncture, however, you will note that with both fans working they are quite noisy. Note the level of this noise and speed, visually and audiably for reference for the next test to see whether the computer control is working.

Now turn the A/C off and let the car start to warm up and when the temperature approaches the 90 degree C mark the fans should start to operate at low speed IIRC (if I recall correctly) and this is how they should operate with an outside ambient temperature of 5 degrees.

If one of the fans still does not work then you may have to overhaul that fan motor. There is a write up on Rennlist with photographs on this procedure, so do a search to locate it.

When you have finished these test let us know where you are at and more help can be given.

I will now do a quick review to check whether my memory has served me correctly so far. If I have made a mistake I will advise. I not sure whether one fan starts at low speed and then the second fan cuts in and then they both go to full speed if the engine temperature keeps raising as they are computer controlled.

Tails 1990 928 S4 Auto

 

Both fans should operate at the same speed.

Clean and check all of the battery connections, especially the medium-sized red wires on the positive battery post.

Carefully check the fuses - it is a good idea to just swap them.

If one fan still doesn't run, you can check for power at the non-operating fan connector while the other fan is running. If you have power, the fan motor has failed. If there is no power, you have a circuit problem.

It is usually much less frustrating and much less expensive to learn how to fix the problems yourself than it is to pay someone else to train on your car...

 

Paul,
Wally P has corrected one of my mistakes regarding the operation of the cooling fans, in that both fans work together at the same speed. Wally is an acknowledged experts of 928, so I would suggest you listen to his advice, especially to his advice in his last paragraph of post #20.

If you are willing to fix your own problems you will obtain excellent assistance from members of Rennlist and contributors to this forum.

I have refreshed my memory by reading the WSM on the engine cooling system especially the section contained on pages 19-11 through to 19-25 as well as the Service Information Technik manual of the MY 1987, which also give an excellent description of the Engine - Cooling regulation on pages 9-02 through to 9-11 and both write ups give a trouble shooting guide to repair the system.

I have mention these reference, as they are all contained in Jim Moorehouse's Technical CDs. A must have set if you are willing to have a go at your own repairs.

The cooling air regulation is monitored continuously and a signal is passed back to the control unit every 20 seconds on the condition of the system. If a fault occurs, the cooling air flaps will be opened to 100% and the radiator fans will operate at maximum speed. This is what we wish you to achieve in the first instance.

Keep us posted and we can guide you through to achieving a fully operation cooling regulation system at minimal expense except for your time.

Tails 1990 928S4 Auto

 

No, both fans should always work together. A fairly common problem, check the fuse and fuse holder for the fan not functioning, if they're ok then swap fan connectors over and see if the fault also swaps. On my car the cooling flap control unit (finned unit on front right of engine compartment) failed and caused flaps to stay shut, I replaced the controller but many just manually open flaps and then pull the fuse.
Best of luck
Joe.

 

Oops, just noticed the second page and you've already got the info. Hope you succeed!

 

Just took a closer at the only motor I can find nearby the crank.
I only see 1 motor with a rubber seal on it (about 6 cm wide/12cm long). Is this the motor you're talking about because I cant see how to connect the existing crank to this motor. Under the rubber housing I think I feel a **** wich can be turned. I didn't feel like tearing off the rubber protection.

Should there be a 2nd motor nearby ??? The crank is positioned in the middle of the colling flap-unit slightly to the left (looking down onto it) and the motor is positioned just slightly to the right. So the crank is not in a upright position when I connect this crank to this motor (still follow me ?).
Are there maybe 2 cranks involved here ? Could it be the previous owner removed the whole motor ? Or am I just incorrect and the motor I mentioned IS the motor is should use ? If so any tips ? Maybe when I remove the rubber protection everything gets much clearer.

I now used a tiewrap to fix the blades in a 100% open position. I'll take her for a ride in a moment. Now first I'm gonna check the fuses for fault on 2nd fan.
I'll inform you in a moment.

Thanks,
Paul

 

Just drove about 100km highway and city. Temperature now never comes above 89 degrees! I think my temperature problem is now over.
Tomorrow I have an appointment with a Porsche specialist to examine a oil leakage. I'll ask these guys to take a look at the fan problem. As I mentioned earlier both fuses are not broken. I even swapped them to exlude 100% the problem is caused by those fuses. I'll let those guys swap the power leads and see what happens.

For now thanks a lot for all your input.

I'll post a follow-up after I've been to the specialist.

Thanks,
Paul

 

what color is the oil leakage?? its usally a loose oil pan or most likely a weeping powersteering reservoir connection

 

I can see some fluid a bit to the right front of engine. It looks transparent, it's not red. I see a little bit of oil lying there on I think an iron pan. Under the car I see two spots on the left side on the floor. I think it's engine-oil but I'm not sure. I get the impression the level of engine oil has dropped the last 2000 km.
It is'nt much I presume but somebody told me it's leaking on the distribution belt (timing belt). I can't verify this myself and the guy told me it's not good if it leaks on the belt. Therefore I made the appointment with the Porsche specialist to inform me how bad it is. I intent to keep this 928 for the next 10-20 years like my 911.
I already own a '85 911 carera cabriolet wich is my 3rd car (1st = '09 Chevy Silverado, 2nd = '09 Jeep Wrangler Rubicon). Like the 911 the 928 will be used very rarely as my 4th car so I must think twice if the repair of the (hopefully minor) leakage is worth it. I intent to drive maybe 3000 km a year. I also read that the 928 is nutorious sensitive for oil leakages when the car is not used regulary. My 928 S4 has driven only a total off 40km last year, maybe this has anything to do with the leakage.

Thanks.
Paul

 

When I first checked the fluid levels I saw the steering fluid resevoir was a bit low. I topped it off 2 weeks ago to max. but I now its a bit under max.
Maybe this has anything to do with the leakage....

What do you think ?

Thanks,
Paul

 

Paul,
Good to hear that your jacket water cooling temperature is now normal.

There should be two electric motors at the front of the engine:
1, The flap motor is just to the righ of the centre line in front of the A/C condenser (radiator) and
2. The other motor to move the headlights up and down is located on the far right, looking from the front of the car.

Both motor have ***** under the rubber covers, so that you can manually open the cooling flaps and manually wind up you headlight into their operating position, in an emergency.

The flap's push rod is located nearly right on the centre line or a little left. The rod is fitted with 2 spherical ends that clip over the motor crank spherical ended bolt and the flap actuator arm bolt.

The rubber cover should be able to be removed easily and the crank should be clearly visible, however the crank may not be positioned in the park position with the ignition off and the rod will not fit as the flaps should be closed and you have them 100% opened.

Have you checked the fuse for the flap motor yet and have you checked to see whether the motor operates? If the crank is not in the parked position and you connect the push rod then the flaps will be partially opened and if there is a fault with the motor then this is the position they will stay, so it is better that you leave the flaps zip tied in the 100% opened position and just check the motors operation by the movement of the crank.

+1 to mrmerlins comments. Some 928 engines use oil and this is noted in the Operators Manual, however the oil pan gasket is known for leakage. Many owners change out the pan gasket and install a silicone gasket to stop the leakage, however, the leakage can be contained if the pan gasket bolt as just nipped up at each oil change as the bolts tend to become slightly slack.

The power steering reservoir is also known for its leaks and the jublee clips attaching the hoses to the reservoir should be checked for tightness and in come cases the hoses renewed if the ends get compressed too much and crack axially and leak.

Another known source of oil leakage is from the cam tower gaskets as the cam shaft covers are sealed by bolts that bottom out in the bolt holes and the force on the gaskets is applied via rubber "O" ring located under cap washers under the head of the bolts. When the gaskets and "O" ring harden and set from age and heat is the problem they develop oil leaks. Any oil leakage usually runs to the rear of the engine and drips onto the exhaust pipe and the burnt oil smell can be picked up through the cabin vents.

In addition you can get oil leaks into the spark plug holes. This can be checked by removing the spark plug boots and viewing the bottom of the holes with a torch. These leaks will not be visible under the car.

Other oil leaks can come from the cam shaft circular end covers as the sealing "O" rings also harden and set.

I have listed the possible 928 areas of leakage to allow you to fully check the engine out when the under engine fairing is removed.

To see whether there is any oil leakage onto the timing belt, remove the air intake tubes and look down on the cam shaft driving/timing belt through the holes in the top of the timing belt covers. Start the engine up and at idle the belt can be inspect for it whole length, however the aft side of the bet is not visible, but you should be able to locate any oil leaks or damage. If a full inspection is required the covers must be removed.

Tails 1990 928S4 Auto

 

I was chasing a non working fan (same as yours) last November. Here's the link to the thread and the fix: https://rennlist.com/forums/928-foru...ion-fixed.html

If you go through everything I did, you WILL find the problem. Many of the guys here helped to solve the problem. Mine was a cheap pair of chineese fuses installed by the PO.