Oil Temps

SeaDweller · 05-09-2003, 11:22 AM

I'm confused (it's chronic I'm afraid

) about the workings of the Carrera fender mounted oil cooler. I've seen various temperatures mentioned at which the fan engages, and I've also seen different references (including Andersen's) as to what is hot, and too hot.

My Targa will run at the 90 degree celcius mark without the A/C, but will run up pretty quickly with the A/C on. I've yet to hear my front cooler fan engage, so I guess it must be accurate that the sensor is set to engage the fan at 245 degrees farenheit.

According to Andersen, 245 degrees is right between "hot" and "too damn hot." Why then would Porsche set the thermoswitch activation temperature at 245 degrees?

If the fan drops the oil temperature 15 to 20 degress, then the engine will be operating in the 225 to 245 degree range, which seems too high to me. Wouldn't it make sense to have the fan kick on at 225 degrees?

pbs911 · pbs911's Garage

You can get a new sensor that comes on at the lower temp. I think it is a BMW part.A BMW sensor. I agree that the 245 degree activation for the fan is too high. Mine is manual. I switch when the fan on whenever the oil temp goes north of 200.

rfix'n · 05-09-2003, 12:11 PM

I have a manual switch as well, along with a recently installed numberical temp guage. I switch it on when I see the needle getting close to 210. I don't believe the fan lowers the temp by much more than 5 degrees.

Tim Polzin · 05-09-2003, 12:15 PM

Michael:

I think the fan came standard on 87's and later. My 86 does not have one. If you are not hearing it, perhaps it is not there.

Tim

masraum · 05-09-2003, 01:42 PM

Yes, I can vouch for the fan coming on at 245.

I think the problem with these temps "hot, too hot, and too damn hot" is that they aren't absolute. If you get to 250 occasionally sitting in traffic it is not a terrible thing as long as the temp comes down when you start moving. If you sit in traffic for hours at 250 that is not good, but I have heard BA in a few spots say that those temps are more of "extended running at these temps" is bad.

Due to the design of these cars the temps will go up and down and depend upon what is going on.

In my '88 the temp once fully warmed and on the road will run right around the top edge of the first white mark (90 deg C)

rfuerst911sc · 05-09-2003, 03:01 PM

Today was a very hot day in Central Florida,aprox. 95 degrees.I made a trip of about 70 miles including highway and stop and go traffic,my car is a 83SC with a Mocal cooler in the front passenger fender with fan that is manually controlled.With the AC on high the entire trip my oil temps never got any higher than 225 and that was sitting in traffic,on the highway it would settle in at about 210 driving at about 75 mph.I really like the ability to turn the fan on manually,I normally keep it off until the temp gets close to 200 then flip it on and forget about it.

APKhaos · 05-09-2003, 04:05 PM

Michael,
I'd be more concerned if you were hearing the fan - none fitted on your 85. The fans were added in the 87 model year.

jbripps · jbripps's Garage

Hey all,

I have an '85 also, and I have the vented piece in the front passenger wheel well........isn't that the fan? Was this added after-market?

thanks,
Jon

masraum · 05-09-2003, 07:34 PM

The fan should sit in front of the cooler. The vented shield that sits on the back of the cooler in front of the tire is primarily to keep debris, rocks from the tire, or the tire in the case of a blowout from damaging the cooler.

Wil Ferch · 05-10-2003, 06:02 PM

For reference, the right-rear fender mounted thermostat will start sending oil to the front cooler at about 180-190 degF...small changes over the model years. For the 87+ cars that use a factory fan for the front cooler, it activates at 244 degF. A C2 switch replacement or BMW part can lower the activation temp. You can elegantly add a manual switch and use the pre-cut hole ( under the vinyl in the dash) that would be used for the rear wiper switch, between the left two gauges near the bottom...just feel for the hole with finger pressure, it's there.
--Wil Ferch

SeaDweller · 05-12-2003, 04:38 AM

Oh, see, I learned something.........

I thought all Carrera coolers had the fan!

Does my cooler have the provisions to bolt on the factory fan and thermostat found on the '87 and later cars? Can I assume there's a blank spot on the fuse panel for the wiring?

Wil Ferch · 05-12-2003, 05:52 AM

Yes and no...
Yes, there is a space on the 85 fuse panel to use a round relay ( as I did)...the 85 version of the cooler does not have the bung provision to add a thermostat on the top header tank of the oil cooler. However, the aftermarket can come to the rescue as a Hayden temp probe that fits between the fins can be used....they have a version with a fixed or adjustable temp activation point.
---Wil Ferch

SeaDweller · 05-14-2003, 01:18 PM

Thanks Wil...........Does the '85 version of the cooler have a provision to add the factory fan?

Wil Ferch · 07-03-2006, 08:10 PM

Sorry to get back on this thread so late... thought we were done.

Addition of fan is not a problem, either the factory unit or the SPAL 7.5" as I used. If you mean the top header tank connection point for the inserted temp switch ( on the oil cooler itself), as per factory.... I think only the later versions of the oil cooler have this...not for '85.

- Wil

RichMink76 · 09-13-2006, 07:36 PM

I am putting a fan on my carrera oil cooler and I got the BMW 210F thermo switch. The problem that I am having is the thread diameter on the switch is smaller than the thread diameter on the cooler. Has anyone ran into this problem? Is there some kind of adapter that I need? I am also installing a manual switch to over ride the thermoswitch.
I did a test wire and everything works, or at least the manual switch worked. Any info would be much appreciated.

Rich

Super_Dave_D · Super_Dave_D's Garage

OK i'll ask a dumb question. Can anyone share with me the best way to manually control the fan (Dont say a switch)? If you do that do you lose the auto cut on that it uses now? Any tips or suggestions on a manual wire set up (like how)?

RichMink76 · 09-13-2006, 07:54 PM

No, you don't lose th e function of the thermoswitch. There are threads on how to do this.

Rich

Barrpete · 09-13-2006, 08:09 PM

Elephant racing sells a fan and installation kit with a temp probe that installs in the fins of the oil cooler. It includes a control module complete with relay and it includes an adjustable thermostat that you can set as low as 170 degrees up to I think around 230 degrees. I just left it at 170 figuring you can have the fan come on too low.

djdsc · 09-13-2006, 10:10 PM

Check out this thread:

oil cooler fan thermoswitch

I used the wiring diagram from flintstone's post along with Wayne's 101 Projects book. I picked up from the parts dismantler a used relay with socket and a rear wiper switch for less than $20. The manual switch installed in the blank on the dashboard as described.

I am not an electrical kind of guy and it all worked the first time.