Randall G.

Hello,

Received my new climate control unit (CCU) today--993.659.047.00. The guys at Hendrick Porsche are okay--even threw in a very nice 2002 Porsche calendar.

As some of you are aware, my CCU would not start the oil cooler fan automatically, which led me to design and install a slow-speed jumper.

Installed the CCU this afternoon:

-My old CCU had never been replaced--964.659.047.00.

-No special wiring required, just plug and play. Everything works.

-The "Max Cooling Button" works. Push the button, the AC starts and the interior fan goes to max speed.

-The oil cooler fan comes on as shown in the below photo:



I'm a little sorry to see my slow speed jumper go, as it would never let the oil get as warm as shown in the photo. Looks to me like the oil cooler fan is being started a bit on the high-side of the band. But, that's the way it is. This is the same temperature a donor CCU started the fan at, and the temp. sensor is brand new. These are the only two things that influence the fan's starting point.

Finally, a photo of the installed unit:

horst

how much was the part, Randall? Looks good.

Randall G.

Hi Horst,

The CCU was "only" $760 + $12 shipping = $772 from Hendrick Porsche. That's pretty much cost on a $1140 list price unit. Don't know how they can sell it for so low, but I'm not complaining.

Kevin

Randall;

Happy New Year! Was you donor CCU off a 964? Now that you know the temps, what did you find in the used market? Regardless its nice to see it up and running.

Adrian

Dear Randall,
I have to correct a small ommision in your statement about what influences when the oil cooler fan cranks up. The primary influence is actually the oil. Getting oil to the sensor so it can read the temp of the oil and for the ccu to react is a mechanical function. It is solely dependent upon when the oil cooler is actually opened to the oil flow. The thermostat controls this. Variations in the temperature ranges are dependent upon the theromostat opening point. My oil cooler fan cranks up earlier than yours.
Outside air temp plays a significant role as well in whether the fan ever cranks up. You may also find that the internal settings of the new ccu may be slightly different as well. Slightly different programmed ranges.
Why is this important. The first thing to check if the oil cooler fan is not running but your temps are high is, "Oil Cooler Open" yes or no. The temp indication is not oil temp but engine temp. There is no visual indication of oil temp from the oil cooler.
I also ask all readers of this thread to note that Randalls statement about his controller change is from model year 1991 onwards. May not apply to certain RHD versions either.
I would appreciate though Randall a copy of the first photo via email. This would be very useful and it is very nice quality,
Ciao,
Adrian
911C4

Michael Delaney

Randall, Congrats on your repair. I know you have been toying with this for a long time. On the up side you have become the resident expert on troubleshooting the oil cooler fan system. Thanks for all the great posts while you were doing this. Roy BTW: I was in Laguna Beach over Christmas for a wedding. Thought about calling you for a beer, but time ran too short.

964Cab

Hi Randall,

When does your oil cooler fan go into FAST mode ? I assume that picture illustrates when the oil cooler fan goes into SLOW mode ?

My cars never get that hot (at 9'Oclock) so that explains why I never hear the oil fan click on.

A jumper test does kick my 964 SLOW/FAST oil cooler fan ON, but I lack SLOW mode via a jumper test on my 993.

Take care,

Patrick

Randall G.

Good morning everyone,

Happy New Year Kevin! .... I found that the used parts dealers that might warranty a used CCU--e.g., PartsHeaven--wanted something like $400-$450. Buying a CCU on Ebay seemed to be a matter of luck, but you could get one at a very good price--even less than $100. But, I was afraid of new problems a used CCU might introduce, and Hendrick's cost/near-cost price made the decision to go new a little easier.

The donor CCU that Andial had installed in my car temporarily was from a 964--'93, I think.

Adrian is correct .... if the thermostat doesn't open, the oil cooler resister (i.e., temp. sensor) will never get heated, and the fan will never start. My thermostat opens at just below the third white mark (8:00 or 194F position).

In "real-life" driving, I believe the fan may start a little earlier than it did when parked in my garage. I say this because real-life driving will likely allow the sensor more gradual heating time, rather than "rushing up" on and overshooting its setpoint.

Adrian--I'll send you the pic tonight when I get home.

Roy ... sorry I missed you while you were here. As you know, Laguna Beach is immediately north of me--beautiful city!

Patrick ... don't know when the fan starts in fast-speed on my car, as the oil starts to cool once the fan starts in slow-speed. So, short of disabling or overloading (with heat) the slow-speed fan, I'll never see it start in fast-speed. I do know the manual specifies a start point of 115C = 239F. Unless you get stuck in traffic on a warm day--or leave the car idling in garage for an extended period--your 964's engine isn't likely to get warm enough (past the 9:00 position) to start the fan.

MikeF

Congratulations Randall. One interesting point...the CCU on my 94 964 does not have two choices for cooling (ie., no "max" settinig). There is just one long button with a snowflake on it for AC. Adrian, when and why did they change this?

Just curious.

slant911

Randall,

Looks REAL NICE. I too had the same question as above. Mine has just one long A/C on button (Don't get me started on the A/C on thing). BTW - the snowflake on mine is worn off. Pressed one too many times.

MikeF

Randall...I couldn't help but notice in the picture that at idle, your car idles e-x-a-c-t-l-y where mine does. Birds of a feather I guess....

Randall G.

Hello,

>I couldn't help but notice in the picture that at idle, your car idles e-x-a-c-t-l-y where mine does. Birds of a feather I guess....

Wow, that is an interesting coincidence. Of course, my idle wasn't this way until just a few months ago. Previously, it was pretty much in the middle between the big (1k) tic and the third (next lower) small tic. About 880 RPM (as set by Todd Knighton at Protomotive).

I thought the second, "max cooling," AC button was added late in the 964 run. But, since Mike's '94 doesn't have it, I guess not. Since my 1/94 Road & Track article on the '95 993 clearly shows two AC buttons, I must assume the feature was added with the 993.

What it does, per my 993 owner's manual:

"The flaps to the windshield and footwells are automatically closed, the temperature control (5) is set to maximum refrigeration and the fan set to stage 4.

The refrigerated air comes out via the centre and side vents only."

Slant ... your worn snowflake (on the AC button) is surely a product of those Las Vegas summers .

speedster 94

hallo
The doubleswitch came only in the 993 and then you have a electric Flap on each side of the Footwell (Big Hose from Rocker to
Panel ) to actuate . If installed in the 964
it has no function. I have one of those and would sell it for 350 $ incl. Shipping ,guaranteed to function proper.If somebody is interested mail me.
Harald

964Cab

Speedster: Randall's 964 actually has a 993 engine and so his new 993 CCU works as a 993 instead of a 964.

Patrick

Randall G.

Hi Patrick,

Very kind of you to say, but my HVAC/oil cooler system is completely 964 .... The CCU I bought--even though it has a 993 prefix--is actually for a (in my case '91 C2) 964.

There may be one or two other small tidbits I'm overlooking, but about the only 993 engine/CCU interface I can think of is the signal from the CCU telling the DME the AC is on.