Auxiliary Oil Cooler Fan - Some Questions

[bbarrington]

Hi. I have an '88 Carrera and I suspect the fan for the auxiliary oil cooler (up front) has not been working for some time. I've never come close to overheating, so I haven't been that concerned. But now that I'm locked down, I thought it might be a good project for me. The reason I don't think it works anymore is that I have never heard it running. Does it only run if the engine is on?

Anyway, at nearly $600 for a replacement, I want to be certain that a) it really isn't working, and b) replacing it would fix the problem. (It might be an electrical or thermostat issue instead).

So, how do you go about testing for this? Anybody BTDT?

Thanks.

[86 911 Targa]

Assuming you have the factory oil temp sensor,
the fan will not activate until the oil temp
reaches 246F.

Way too hot!!!!

My suggestion would be to install a 210F oil switch.




^^^^^
I installed one of these.

Also, your M/Y 1988 should have a dedicated oil cooler fan relay
2nd from the left on the relays/fuse panel.
and fuse.

On temp=210F
Off temp=197F

Best,

Gerry

[Discseven]

BB... to see if fan itself is the issue, can jump wires from car's battery to fan. Is good to have fuse on positive jump wire---very low amp... maybe 10amp. Suggest making wires long enough to reach from battery easily to anywhere around the car... should keep those wires as part of your evolving "tool kit." If anything's sorta wrong with fan, fuse will burn instead of fan. Can do without fuse but some risk. If fan's OK, you'll hear it run. If jump connections are good and fan doesn't run... bad fan. Am not familiar with '88 aux oil cooler setup so not sure how easy or hard it is to access fan's terminals. One way or another am sure you can sort it out.

[911pcars]

Suggest wiring in a parallel ON-OFF switch to manually switch the fan ON/OFF at your pleasure or to confirm it's operation.

Your existing circuit should have a relay to control current load in the circuit. If you add a switch, connect directly to the relay to manually do the same.

Sherwood

[GH85Carrera]

My 85 came with the cooler, but no fan at all. I added one back in 2007. It is a simple toggle switch, with a human interface. Sine I am the only driver, I flip it on when the temp hits 200 degrees and climbing. Now it never gets to 220.

[86 911 Targa]

Originally Posted by Discseven

BB... to see if fan itself is the issue, can jump wires from car's battery to fan. Is good to have fuse on positive jump wire---very low amp... maybe 10amp. Suggest making wires long enough to reach from battery easily to anywhere around the car... should keep those wires as part of your evolving "tool kit." If anything's sorta wrong with fan, fuse will burn instead of fan. Can do without fuse but some risk. If fan's OK, you'll hear it run. If jump connections are good and fan doesn't run... bad fan. Am not familiar with '88 aux oil cooler setup so not sure how easy or hard it is to access fan's terminals. One way or another am sure you can sort it out.

Good point on the fuse.



^^^^^

Here's what I used.

Best,

Gerry

[uwanna]

Originally Posted by GH85Carrera

My 85 came with the cooler, but no fan at all. I added one back in 2007. It is a simple toggle switch, with a human interface. Sine I am the only driver, I flip it on when the temp hits 200 degrees and climbing. Now it never gets to 220.

Glenn,
I added a switch in the cabin to energize the fan relay like you did. If you feel around
the vinyl covering on the instrument cluster, you will find a cutout that you can insert
a small switch into (can find at any FLAPS).
As Glenn mentions, turn on the fan at 200deg, if you wait till internal 220deg
temp sensor activates, the heat soaked oil system takes forever to cool down.
I have a 964 3.6 in my '82SC (with an added on, on motor stock oil cooler) and if I switch
on the cooler fan at 200deg, it never gets over 210 even on the hottest days.

[wildcat077]

I also installed an on/off switch for my cooling fan , especially since my car now has a 3.6 , it doesn't like sitting in traffic , although once i'm moving it has a big ass Patrick Motorsports front mounted cooler which makes the engine run at the perfect temperature !

[GH85Carrera]

The fan does also help on really HOT days on long road trips. Coming back from Monterey, CA to Oklahoma one "gets" to drive through some real beauty spots of California. Bakersfield and Needles are places everyone should see once. And one very brief visit is enough in the summer. As I drove through Needles it was 118. The AC struggled to keep me cool, but I never broke a sweat. Even on the highway I was running the fan. The engine temp stayed below 220. If I turned it off it would start creeping up. Turn the fan back on, and the temps came down to 220. And like the photos in uwanna's posts, my temp gauge is calibrated with numbers. I have used my IR thermometer and read the oil filter, engine parts and the front cooler, and the temps are very close to the temp gauge.

[darrin]

Harrington -- note that there are a number of far cheaper replacement fan options available -- no need to drop $600 for a plastic fan

[bbarrington]

As usual, this community is great! Haven't had a chance to muck with it yet, but will climb under this week and see if the fan is alive.

Thanks again for all the great suggestions.