SC w/Carrera Oil Cooler - Still Too Hot?

[ikarcuaso]

I recently upgraded the trombone oil cooler in my SC to a used radiator-style cooler from a 3.2 Carrera. I don't have a fan.

With daytime temps only in the 70s, during normal city driving, or semi-aggressive highway driving, my oil temp. gauge tends to look like this:



Is something wrong here? I tried adding a cool collar and front oil cooler scoop but have noticed little difference. For it to subside while still driving, I would need to cruise for awhile on the freeway (not an immediate decline by any means).

Thanks for any help.

[aigel]

Measure the actual temperature at the sending unit. Use an IR thermometer. Then compare to the reading on the scale. Maybe it is off. If you search on the forum, there is posts that tell you the absolute temp. Those temps you see there may be okay for 15 minutes of track driving - if you change the oil afterwards - but should not occur in street driving.

Of course, Porsche put the red much higher, so in their book you are just fine. But that's a discussion for another thread - look it up.

George

[edgemar]

Mine never went above 9 o'clock when the car was moving at speed.

[Oh Haha]

Yes, that is too hot if you are just driving around on the street. My SC has never gone above 8o'clock, even in 90-100 degree temps(street driving). We did a PCA tour last weekend and it was 94 degrees out with 94% humidity. While not on the track, I did some "spirited" driving and the temps never came above 8. I would suggest to check the following right away:

Your thermostat may not be opening properly to circulate the oil through the coolers.
Also, check the oil lines for any pinches restricting flow.

A new sender is cheap, of course, so try checking the oil temp at the tank as suggested above. Youmay need a new one is all.

EDIT:
While additives are poo-pooed by some, I have found good success with the Lucas oil additive. While it won't perform miracles, it may help your temps come down some.

[johnnyo]

Check to see if the oil lines going to the front mount oil cooler are getting hot if not it may be as OH haha said that the thermostat is not opening at the correct temp, if lines are infact hot the fan assembly will be needed to allow oil cooler to achieve better airflow through it to achieve cooling, this especially is advisable at lower speeds where airflow to cooler is reduced, my car also never seems to surpass the 8 oclock possition,

[911pcars]

"I don't have a fan."

If gauge and sending unit are okay, it's probably insufficient air flow in the fender area. A fan and some ductwork to outside air will help (refer to many threads in the archives).

Sherwood

[Miguel Antonett]

I tried "all of the above" methods to keep oil temp at a confort level while being at the track or city traffic; the real solution to the problem is to install a front valance oil cooler.

[aigel]

Originally posted by Miguel Antonett
I tried "all of the above" methods to keep oil temp at a confort level while being at the track or city traffic; the real solution to the problem is to install a front valance oil cooler.

.... until you hit a curb in city parking or when going off track. There is a reason the factory put the oil cooler in the fender. Safest place. If one cooler is not sufficient for summer heat, install a second fender oil cooler on the driver's side. Of course only after you checked all the above. Just my two cents.

George

[Gunter]

My SC has the Carrera cooler without fan, no heat issues.
Some observantions: If your Tach is correct, increase the idle by about 50 RPM.
Oil pressure looks low at 800 RPM, consider installing the restrictors in the cam lines to increase pressure at idle.
Are the fins on your cylinders clean? Good air flow from the fan?
At the temp indicated, the oil lines to the external cooler should be hot (External thermostat wide open)
Try another sender if you are not sure with this one.

[ikarcuaso]

Thanks for the replies.

The oil lines that connect to the top of the oil cooler are definitely hot after driving. I'm going to get an IR thermometer tomorrow. Assuming the sending unit need replacing, is VDO-323055 the right part?

[jaydubya]

My experience with a fan on the Carrera cooler in my SC is that it helps primarily when moving slowly such as in traffic. Once you get up to speed the airflow from the fan SHOULD be small compared to that generated by the movement of your car.

The problem with the Carrera cooler is that it just doesn't get much airflow in that location. In the Carreras, the factory notched the lower part of the bumper to help with airflow. This will definitely help. Make sure that the edges of the cooler are sealed tight against the body. Move your horns if you haven't already done so. Consider blocking off the bottom area under the cooler. All of these things will improve airflow and make sure that air approaching the cooler HAS to pass through it.

All of this said, if your gauge is correct it is reading about 235-240. If you don't have good airflow through the cooler, and given that you don't have a fan, that would seem about right for a SC sitting in traffic. Ideally you'd like to get it down to 210-220 or so under those conditions. That's really all you can expect with the Carrera cooler. Without the Carrera cooler, my SC would just continue to climb up to and past 250 in traffic.

[herman maire]

What oil are you using? You should be running 20/50 dino oil....maybe the oil your using is too thin. pressure does look a little low .

[Grady Clay]

All of the above are good suggestions. Here are a few more:

There have been some new defective Carrera oil coolers in
the parts chain. The defect is oil getting past the internal
separation in the top part of the cooler. This allows hot oil
to come into the hot tank, leak past the separator and return
to the thermostat not effectively cooled.

An easy way to test is to use an IR thermometer and compare
all the surface temperatures. The oil should get progressively
cooler from inlet side of the top tank to the bottom tank and
then back to the outlet side of the top tank. If the outlet side
of the top tank is warmer than the bottom tank, something is
definitely wrong.

The definitive test is to remove the cooler and out a bright light
in one port and observe the other port. No light should pass
between the two sections of the upper tank. A competent
radiator shop can repair (and improve) the Carrera cooler.

I am a proponent of using a fan on the front cooler. You should
be able to switch control it in addition to the thermostat switch.
There are aftermarket fans that are considerably more powerful
(and less expensive) than Factory.




Cooling the engine at the source of the heat (heads and
cylinders) is very desirable. Your ‘82SC can add to the
cooling with just the replacement of the crank shaft pulley
to one from a ’78-‘79 SC or 930 Turbo. This changes the
fan ratio from 1.68:1 to 1.81:1 and increases the air cooling
about 8%. The oil temperature may not change much but
will help protect your heads and other engine parts. This
also improves you’re A/C performance.


One of the reasons for Porsche compromising fan (engine &
cooler) performance is German noise regulations. Not an
issue when cruising across the Mojave Desert.



For the track use:
“Rubbermaid Solution”


Best,
Grady

[Rick Lee]

My SC never went above 212 deg. on a hot day on the track.

My cooling set up was also a Carrera cooler with no fan, a scoop, right fog light removed with flashing in there to direct air onto the cooler, rocker trim removed to expose oil lines, 964 cam oil line squirters and a cool collar. This worked perfectly.

[vash]

get a fan, and notch the underside of the bumper.

[Carl Bauer]

Originally posted by Grady Clay
All of the above are good suggestions. Here are a few more:

I am a proponent of using a fan on the front cooler. You should
be able to switch control it in addition to the thermostat switch.
There are aftermarket fans that are considerably more powerful
(and less expensive) than Factory.

Best,
Grady

Grady,

Can you or someone else recommend a powerful, less expensive fan? I have a Mocal cooler in the passenger fender that should have a fan on it as well.

[vash]

spal fan, 7.5 inch push unit.

[jevvy]

As Vash & Grady say the Spal 7.5" fan is a good fit.

I cut notches out of mine so it would sit flat against the cooler - I also put quite a bit of effort into mounting at the top of the cooler so it doesnt obstruct the airflow from under the bumper:

[stlrj]

You might also have your mixture checked.

I have 3.2 in my 74 with only a trombone up front and the richer I set my mix the higher my oil temps soar. Leaning it out keeps my oil temp from going up beyond 1/4 no matter how hot it gets outside.

Not what you would expect since it goes against everything you would think.

Just throwing it out there in case your engine behaves like mine.




Cheers,

Joe

[dougcl]

It's possible that your engine fan ate a shop rag and deposited shredded pieces all over the cylinders.

Doug