COOLING FAN, ELECTRIC
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Track Day
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From: HIGH POINT, N.C.
COOLING FAN, ELECTRIC
HELLO, NEW TO RENNLIST.I HAVE A 85 928S AUTOMATIC. THE COOLING FAN DOES NOT WORK WITH THE A/C ON OR OFF.RUNS CLOSE TO RED SITTING STILL.OK ON THE ROAD. I HAVE NO MANNUALS(BUT LOOKING ON E-BAY FIRST). I SEEN THE INFO ON GREG NICHOLS TROUBLESHOOTING GUIDE. I DID STEPS #1 TO #3 ,BUT ON STEP #9 I WAS NOT SURE WHAT TO TEST AT THE LOCATIONS #30 AND #87. ALSO,HAS ANYONE SEEN A 928 WITH A PURPLE/BLUE EXTERIOR COLOR WITH A BLUE DASH,CARPET,TWO TONE BLUE AND TAN DOOR PANNELS WITH TAN SEATS? MY 928 HAS THIS COMBO.IS THIS NORMAL,SPECIAL ORDER OR A RARE COLOR COMBO?
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From: Ft. Lauderdale FLORIDA
JS-
Not being the most traveled 928 guy around, I can't remember ever seeing a color combo like you've described. Sounds interesting- post a pic.
My '85 S2 [European version- similar to your car] has the same problem- a booster fan that won't boost. Yuck.
I did the diagnostic and discovered that the radiator sensor is bad. I jumpered it- I'm poor boy until my airline either starts back up or I get another job, so I simply built a jumper wire that goes between both wires so that the fan runs whenever the ignition is powered.
In your case...you need to have your cooling system checked and checked NOW!!!!!! Your car has a problem. That fan is designed to help the air conditioner- It blows against the condenser and it is small and weak, doing little to cool the engine-
Don't crack a head!
Normy!
'85 S2
Not being the most traveled 928 guy around, I can't remember ever seeing a color combo like you've described. Sounds interesting- post a pic.
My '85 S2 [European version- similar to your car] has the same problem- a booster fan that won't boost. Yuck.
I did the diagnostic and discovered that the radiator sensor is bad. I jumpered it- I'm poor boy until my airline either starts back up or I get another job, so I simply built a jumper wire that goes between both wires so that the fan runs whenever the ignition is powered.
In your case...you need to have your cooling system checked and checked NOW!!!!!! Your car has a problem. That fan is designed to help the air conditioner- It blows against the condenser and it is small and weak, doing little to cool the engine-
Don't crack a head!
Normy!
'85 S2
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Joined: Jul 2001
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From: Midland, Texas
JS,
Fluid levels o.K?
Norm's right about the jumper -30 & 87-
Check under the front end... is everything there,
pans, dams, cooler lines?
Try cleaning the core fins by flushing from the back side > forward. And see if something is blocking the space between radiator/cooler.
Mine will run a bit hot at idle but cools IMMEDIATELY upon moving.
Before you start swapping things do a back flush.
Back to the Fan, did you check the archives on this site?
Later, good luck.
John S. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
Fluid levels o.K?
Norm's right about the jumper -30 & 87-
Check under the front end... is everything there,
pans, dams, cooler lines?
Try cleaning the core fins by flushing from the back side > forward. And see if something is blocking the space between radiator/cooler.
Mine will run a bit hot at idle but cools IMMEDIATELY upon moving.
Before you start swapping things do a back flush.
Back to the Fan, did you check the archives on this site?
Later, good luck.
John S. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
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From: Ball Ground, GA
J.S.,
First, ALL CAPS IS CONSIDERED SHOUTING.
On cooling - overheating at idle and in traffic is usually an air flow problem, while overheating at highway speeds is usaully a coolant flow problem. Of course, extreme coolant flow problems can and will cause overheating any time.
The earlier cars commonly have air flow problems. The electric fan is strong enough, but it may not come on early enough, and the A/C switch is not too good. The fan is triggered by three different switches:
A cooltant temp switch mounted in the left forward face of the radiator. You can get a replacement switch that will trigger the fan at a lower temp, which can help in marginal cases.
A temp switch mounted on a stem on the A/C receiver/dryer. This doesn't seem responsive enough to me. I think that a better choice would be an additional relay that triggers the fan with the A/C compressor clutch.
A temp switch mounted in the intake plenum. This is primarily for cool-down after shut-down, and will cause the fan to run with the ignition switch off, if the intake is hot enough.
The air flow problems are often made worse by the fluid clutch on the belt-drive fan. A replacement is pretty expensive, but I developed a method of refilling the silicone fluid that will sometime help.
Another factor with air flow problems - If your bottom engine cover is missing, if the spoiler is missing, or if there are gaps around the radiator, hot air can recirculate while you are sitting still.
First, ALL CAPS IS CONSIDERED SHOUTING.
On cooling - overheating at idle and in traffic is usually an air flow problem, while overheating at highway speeds is usaully a coolant flow problem. Of course, extreme coolant flow problems can and will cause overheating any time.
The earlier cars commonly have air flow problems. The electric fan is strong enough, but it may not come on early enough, and the A/C switch is not too good. The fan is triggered by three different switches:
A cooltant temp switch mounted in the left forward face of the radiator. You can get a replacement switch that will trigger the fan at a lower temp, which can help in marginal cases.
A temp switch mounted on a stem on the A/C receiver/dryer. This doesn't seem responsive enough to me. I think that a better choice would be an additional relay that triggers the fan with the A/C compressor clutch.
A temp switch mounted in the intake plenum. This is primarily for cool-down after shut-down, and will cause the fan to run with the ignition switch off, if the intake is hot enough.
The air flow problems are often made worse by the fluid clutch on the belt-drive fan. A replacement is pretty expensive, but I developed a method of refilling the silicone fluid that will sometime help.
Another factor with air flow problems - If your bottom engine cover is missing, if the spoiler is missing, or if there are gaps around the radiator, hot air can recirculate while you are sitting still.
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From: Ft. Lauderdale FLORIDA
JS-
If I was a whale Captain at United I still wouldn't have enough money to do all the things I want to my shark!
HOWEVER...if you are good with your hands you can solve 90% of your cars problems yourself. Having an A&P ticket gives you a big leg up on most of us.
-They say the most dangerous thing in aviation is a pilot with a wrench in his hand... Beware! Here I come with a whole socket set!
Really though, the best investment you can make during your tenure as shark pilot is a set of manuals. You will find these invaluable! You can put one next to the toilet for interesting reading too.
[I've had some of my best inspirations this way...]
Normy!
'85 S2
If I was a whale Captain at United I still wouldn't have enough money to do all the things I want to my shark!
HOWEVER...if you are good with your hands you can solve 90% of your cars problems yourself. Having an A&P ticket gives you a big leg up on most of us.
-They say the most dangerous thing in aviation is a pilot with a wrench in his hand... Beware! Here I come with a whole socket set!
Really though, the best investment you can make during your tenure as shark pilot is a set of manuals. You will find these invaluable! You can put one next to the toilet for interesting reading too.
[I've had some of my best inspirations this way...]
Normy!
'85 S2
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From: Insane Diego, California
Good stuff Wally!
On my '79 - there is a doohicky bolted to the front of the air distributor (intake plenum) made of brown plastic with an electrical cable routed to it.
Is this the plenum temp switch of which you speak?
Also, where exactly would that high-temp switch be located on the radiator on my MY? I can't seem to locate it.
Thanks Wally - you da man!
On my '79 - there is a doohicky bolted to the front of the air distributor (intake plenum) made of brown plastic with an electrical cable routed to it.
Is this the plenum temp switch of which you speak?
Also, where exactly would that high-temp switch be located on the radiator on my MY? I can't seem to locate it.
Thanks Wally - you da man!
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Thread Starter
Track Day
Joined: May 2002
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From: HIGH POINT, N.C.
I jumped the wires at the radiator temp switch and the fan worked.The temp never got close to the third white line.After a full warm up down the highway the temp. stayed just over the second line with a/c on and at idle for 10 min at 88F. Thanks for all your input, JSW 
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From: Ball Ground, GA
JS -
Glad that you found the problem.
Be sure to come to Spruce Pine for the Sharks in the Mountains Picnic next weekend. Go to our web site ( <a href="http://www.928gt.com" target="_blank">www.928gt.com</a> ) for details.
Randy,
On most models (and I think that includes the '79, but I haven't looked at one lately) the fan switch is mounted in the front of the driver's-side radiator tank near the bottom. BTW - I think that it is only on '79s that have option M573, which is A/C.
Glad that you found the problem.
Be sure to come to Spruce Pine for the Sharks in the Mountains Picnic next weekend. Go to our web site ( <a href="http://www.928gt.com" target="_blank">www.928gt.com</a> ) for details.
Randy,
On most models (and I think that includes the '79, but I haven't looked at one lately) the fan switch is mounted in the front of the driver's-side radiator tank near the bottom. BTW - I think that it is only on '79s that have option M573, which is A/C.
