Potentially damaging Porsche 911
oil temperatures (Greater than 230 degrees F.) are especially noticeable if you drive in
heavy traffic, or are a regular Club Racer, Time Trial or Slalom participant, especially
in the summer months! What are your options if you have a 1974 through 1989 911 and you
want to seriously address excessive engine oil temperature? It may depend on whether you
subscribe to the dictum that factory parts are the only alternative, and aftermarket
For those pre-1985 911 owners feeling that
Porsche factory parts are their only option, you have an alternative from the Porsche
factory that will optimize oil cooling on your car over your present set up, the 1987 to
1989 Carrera oil cooling radiator system. Out on the road (And track) there are thousands
of 1987-1989 Carreras and their oil coolers out there. The active cooler, with
fan and a protective shroud enclosing the radiator, work well. But does it work well
enough across the varied applications we drivers put our cars through, street, autocross,
Time Trial, Club Racing? It depends.
Lets first look is involved in an
installation of the 87 to 89 Carrera oil cooling system to an earlier car. The Carrera
active radiator, as you would expect, is mounted directly behind the headlight
in the right front fender of your 1974 or later 911. For 85 and 86 Carrera owners, with
some minor modification involving factory brackets and a wiring loom, your oil radiators
may be retrofitted and converted to "active" by incorporating the high output
oil radiator fan introduced with the 87 Carreras.
For owners of 1974 through 1983 911's wishing to
install the 87 Carrera cooler and maintain the "old style" spoiler with the
exposed fog lights, simply have the 1987 Carrera oil cooler mounting tab fabricated and
installed on the upper right side of the spoiler. Depending on the year of the car, a
radiator mounting bracket may need to be fabricated and attached to the back of the right
headlight tub; it was necessary on my 1980 SC installation.
Also, if the Carrera radiator to function to
its full potential, it needs maximum airflow. On 1984 and earlier cars, it is
recommended to notch the right underside of the front bumper to maximize airflow to the
radiator. In addition, the horn must be relocated to accommodate the Carrera cooler;
factory brackets are available.
Should you wish to update your 1978-83 SC to the
1984-89 Carrera front end "look", replace the 1974-1983 valance with the 1987
Carrera valance. This valance has the recessed fog lights introduced in 1984 and the
necessary mounting tab for the cooler. You will have to fabricate the tab if you stay with
a 1986 or earlier valance. Also, a 1984 or later Carrera style windshield washer container
will be needed. The pre-84 bottle is too large and won't fit.
A caution for Porsche 1974-77 Porsche 911 owners
contemplating converting a car delivered without a factory loop cooler. You will also need
to purchase the hardware to get the oil from the engine to the cooler in the right front
fender. This includes multiple sections of brass pipe as well as a right rear wheel well
mounted thermostat that activates the cooler circuit when oil temperature reaches
approximately 182 deg F. Note, a significant amount of heat transfer (cooling) is provided
by the pipe which is lost if rubber lines are substituted.
Once the Carrera cooler is installed, another
option to consider involves the wiring of a dash mounted override switch for the oil
radiator fan. It now becomes your decision to activate the cooler fan rather than having
to wait for the factory thermocouple to activate the fan after oil temperature reaches 244
deg F.(Ouch, thats hot!). With manual override, you must not forget to turn the fan
on, that would be very un-cool.
Parts for the conversion to the
"active" Carrera cooler are all factory. In my experience, the oil radiator with
fan and shroud will cost from $500 to $1,000 depending on whether you buy new or used. The
Carrera 1984-86 valance is available used for about $200 and you must add a mounting tab
to the right side. New, the 87 Carrera valance is about $275. Budget another $200 to paint
the valance. The fog lights can be obtained for about $250 a pair, or you can wait and
install them later.
The remaining mounting brackets, hardware,
relays, fan control harness, etc. will cost approximately $325 including about $80 for the
new Carrera windshield washer bottle. Bottom line, your looking at a minimum of $1,500 in
factory parts assuming you do all the labor yourself. The cost of the Carrera factory oil
cooler conversion is similar to what you could expect to pay for a high quality
aftermarket Ruf spoiler with hardware, cooler and paint.
Concerning the labor: I had the conversion work
on my 1980 SC, including addition of the override switch and wiring of the fog lights,
fabrication of the upper cooler bracket on the rear of the headlight tub as well as
installation of the 87 Carrera valance and needed windshield washer bottle done at a local
Porsche repair shop. It took approximately eight hours. You can save a substantial amount
on the conversion job if you choose to stay with your 74-83 valance.
Some questions you may wish to consider, is it
worth the expense just for some peace of mind? And, does the 1987 Carrera cooler perform
to the point where the investment is worthy of consideration?
To some, me included, the peace of mind factor is
substantial. A cooler running engine will last longer and perform better, period! Plus,
the upgrade may add to the value of your car should you ever sell it!
Does the active Carrera cooler perform
significantly better than the loop or an aftermarket (Turbatrol) fender mounted cooler? In
my personal experience on a long summer road trip, as outside the temperature hovered at
95 deg F., driving my 1980 SC on the highway as well over steep grades, with the air
conditioning on, the Carrera oil cooler conversion resulted in a dramatic improvement. At
no time did the oil temperature exceed 205 deg F. Previously, in similar situations, first
with the loop cooler, and later with an aftermarket (Turbatrol) fender well mounted
cooler, the oil temperature gauge crept past the 220 deg F. mark.
In heavy city traffic, the "active"
Carrera cooler has demonstrated it can do the job. I especially enjoy having the option to
activate the "non-factory" fan override switch whenever I the oil temperature
gauge indicates temperatures in excess of 205 degrees F.
What about performance of the "active"
Carrera cooler in Slaloms and Time Trials?
On a hot summer day with a one run PCA Slalom
course, installation of the Carrera oil radiator with fan will just about guarantee that
you'll run out of brakes before you get the oil temperature too high.
Regarding Time Trial performance of the Carrera
cooler, I ran a Time Trial at the Firebird International Raceway located outside Phoenix,
AZ. Here track temperatures was approximately 90 degrees F. At no time at the event did
oil temperature ever exceeded 220 deg. F. Note: at this event, I did have my right front
parking light removed for additional air circulation.
Next, consider these conditions encountered in a
Southern California summer Time Trial. Track temperatures were between 95 and 100 degrees.
I took the car out for the full 20 minutes, and for a few moments toward the end of the
session, the oil temperature was up to nearly 250 degrees F., admittedly too hot. Other
911s and Carreras were getting as hot, some hotter, but much sooner and were pulling in
the pits to cool down after as few as three laps around the course. At this point, I had
made up my mind to replace the Carrera cooler with something better.
By now I had gone through my purist
phase. I had no reservation about changing the stock outward appearance of the car. I
wanted wanting maximum oil cooling for Time Trials and would make no further compromises.
In my experience, the Carrera active"
cooler provides significant, but not the ultimate, reductions in engine oil temperatures.
The Carrera coolers work well in heavy traffic and moderately well in Time Trials and
Slaloms. However because of my primary interest in participating at speed events, I
ultimately went to the next step and installed a Ruf type spoiler and cooler.
Before purchasing the Ruf spoiler and
cooler for my SC, I observed these units in action at several Time Trials. Car with the
Ruf set up, after 20 minutes of continuous track time, were running cool,
seldom exceeding 200 deg F., usually lower. Non Ruf cars ran 20 to 30 degrees
For those interested in Time Trials and Club
Racing, strongly consider installation of Ruf style spoiler with the center
mounted oil radiator. Not only will you run cool, you also pick up front air scoops for
your brakes. If you have a shop do all the work for you, you could spend approximately
To summarize, my history with oil coolers on my
1980 SC started with the factory loop cooler. With this set up, the car ran too hot for me
and I wanted more cooling. Next, I installed Turbatrol aftermarket cooler, which was an
improvement but did not provide enough cool under adverse Time Trial conditions.
Subsequently, I installed the 87 Carrera valance
with the active cooler: Still not cool enough for my taste. Finally, I
installed the Ruf spoiler with center-mounted cooler. I had attained the cool
I wanted. The trial and error had cost me but finally, I was cool.
Bottom line, if you plan to Time Trial of Club
Race your car, take the Ruf approach. I must add that the Ruf
cooler was more than adequate for street driving as well. The only down side is the
possibility of having the spoiler mounted cooler punctured in a parking incident. I have
never experience this as I make it a rule to never parallel park a Porsche.
Decide upon your budget and your short term and
long term goals for the car. Do it, and do it right the first time
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