oil cooler question?

[1975porsche]

Looking for advice , I have a 1975 911 s 2.7 , oil temp seems to be high (230) when driving it a little hard . question , i have a complete oil cooler from front to back on a 82 and an 84 911 what one should i use . Is there a temp that i need to keep the temp up to! thanks Glenn

[garment]

Originally Posted by 1975porsche

Looking for advice , I have a 1975 911 s 2.7 , oil temp seems to be high (230) when driving it a little hard . question , i have a complete oil cooler from front to back on a 82 and an 84 911 what one should i use . Is there a temp that i need to keep the temp up to! thanks Glenn

I just replaced the trombone on my '83SC with a cooler and fan kit from Elephant Racing. I'm very happy with the result. Is your temperature higher "all of a sudden," meaning did it just start to run hot this season? I ask b/c I also had air leaks at the injectors, causing the car to run lean and hot. I bet that if you do use the parts you have laying around, the '82 is a better choice, perhaps others will chime in. Good luck.

[darrin]

I'd use the one from the '84, should have the same radiator-style cooler as the Elephant Racing kit (without the fan) -- the '82 used a less effective trombone-style cooler.

[KNS]

Early '84s had the brass tube coolers, late '84s had the more common "Carrera" style (finned) cooler.

[Reiver]

I'd go with the Carrera unit. I have one on my '83 Euro SC.
Today was 108 degree's ambient and I did an 80 mile round trip to town avg. 70-75 mph.
My max oil temp was 210.
I do/did use the unit fan but have it wired to the dash for control and utilize it in stop/go.
In normal temps...anything up to 95 degree's ambient I'll normally be at 185-190.

[chrismorse]

The oil temp is all you have to gauge the engine's temperature. My fathers 74 ran crazy oil temps, particularly with the ac on. Oil pressure was scary low. He had several rebuilds, the last one a 12K top end rebuild. As soon as he passed the car to me, i ditched the ac and installed an 85 Carrera cooler, brass lines and the factory thermostat, (the best, because it also has a pressure bypass if the oil is cold, so you don't blow up your cooler).

My preference is to have more cooling capacity than I will ever need, so I can be sure that the engine never sees oil temps/engine temps that are destructive.

Magnesium engines do not live long at high temps and they are expensive to fix.

IMHO, what all 911s need is more cooling capacity than they will likely need, so that they can keep the vital oil temps, (and pressure), within safe ranges.

Just like water cooled engines the thermostat keeps the "coolant" at the right temp and thus the metal parts of the engine.

Oh yeah, air does a bit too, so make sure no rats or politicians have packed food or nests inside the air shrouding, (On my 308, I had pack rats, (attorneys/vermin) pack berries and little leaved branches between the carburetors, over the fuel tanks and all around the radiator - took me hours to get all of that trash out of my car - you have been warned :-)


chris

[86 911 Targa]

Originally Posted by 1975porsche

Looking for advice , I have a 1975 911 s 2.7 , oil temp seems to be high (230) when driving it a little hard . question , i have a complete oil cooler from front to back on a 82 and an 84 911 what one should i use . Is there a temp that i need to keep the temp up to! thanks Glenn

Glenn,

I would suggest the radiator (84-89 M/Y)
cooler (with a bung).





^^^^^
And a temp switch like this.

The optimum oil temp is 185f (when the engine cooler opens)
And 210f (when the external thermostat opens up).

The 210f boils off any condensation in the oil.

Good luck,

Gerry

pm me as needed.

[1975porsche]

Thanks to all , looks like I will use the 84 cooler.

[grizzfan]

+1 on any Elephant Racing oil cooling system.

Tom

[KTL]

Actually both the engine's internal t-stat (the one located on top in the infamous "triangle of death/oil leaks" area) and the external t-stat in the right rear wheel area open at the same 83°C (= just over 180°F) temperature. They both have the same insert/regulator piece inside of them.

Totally agree with Gerry that if you get the Carrera style oil cooler with the provision for a thermoswitch, use the BMW thermoswitch that others have used to turn on the fan at a reasonable temperature. The originally specified Porsche thermoswitch is effectively useless because it doesn't switch until something like 240°F I believe?

[grizzfan]

KTL states:

The originally specified Porsche thermoswitch is effectively useless because it doesn't switch until something like 240°F I believe?

According to Elephant Racing their thermostat amidships begins to open around 190 to 195F.

Tom

[86 911 Targa]

Originally Posted by KTL

Actually both the engine's internal t-stat (the one located on top in the infamous "triangle of death/oil leaks" area) and the external t-stat in the right rear wheel area open at the same 83°C (= just over 180°F) temperature. They both have the same insert/regulator piece inside of them.

Totally agree with Gerry that if you get the Carrera style oil cooler with the provision for a thermoswitch, use the BMW thermoswitch that others have used to turn on the fan at a reasonable temperature. The originally specified Porsche thermoswitch is effectively useless because it doesn't switch until something like 240°F I believe?

Whatever switch he uses, it should be used in conjunction with a relay
and, fused circuit.

You are right about the p-car thermoswitch-248f-
Really keeps the mechanics busy............

Best,

Gerry

[Reiver]

Originally Posted by 86 911 Targa

Whatever switch he uses, it should be used in conjunction with a relay
and, fused circuit.

You are right about the p-car thermoswitch-248f-
Really keeps the mechanics busy............

Best,

Gerry

Or, just put a fused/relayed switch on the dash and control the fan yourself...cheaper and easy to do with positive control.

[KTL]

Originally Posted by grizzfan

KTL states:

According to Elephant Racing their thermostat amidships begins to open around 190 to 195F.

Tom

I think you mean, their thermoswitch for the oil cooler fan? I'm going to go out on a sturdy limb and assume Elephant uses the lower temperature "BMW" switch that was sort of discovered here on Pelican. Chuck @ Elephant has been on this forum since the beginning and he sees & uses a lot of the little tricks people have shared over the years. That comment is not intended to diminish his own ingenuity he's demonstrated in creating the smart stuff he's brought to market. He's a sharp dude & does excellent outside the box thinking.

Just for reference in case anybody searches this in the future, here's some typical misinformation from the '84-'89 Carrera Bentley service manual, as well as a photo of the factory '84-'89 911 service manual updates (microfiche- sorry for the crap quality) taken from the page for the Carrera oil system. Bentley shows 188°C (370°F- yikes, who proofread this?) incorrectly/typo and the Porsche service info shows the correct 118°C (244°F) temperature trigger that I mentioned.




I don't know about the 911s earlier than the Carrera, but I do know the Carrera fog lights are fused and relayed. So if you don't use your fog lights (or you eliminated them- i'm admittedly a hater of fog lights) then you can use the existing fog light switch/wiring to trigger your fan whenever you want to. I did this on my former '87 Carrera and it worked fine. Just need to have the main light switch on in order to power the fog lights

[86 911 Targa]

P/N 911-612-080-04
^^^^^
I used this harness.


^^^^^
And placed the relay here.

Good luck,

Gerry

[86 911 Targa]

Originally Posted by KTL

I think you mean, their thermoswitch for the oil cooler fan? I'm going to go out on a sturdy limb and assume Elephant uses the lower temperature "BMW" switch that was sort of discovered here on Pelican. Chuck @ Elephant has been on this forum since the beginning and he sees & uses a lot of the little tricks people have shared over the years. That comment is not intended to diminish his own ingenuity he's demonstrated in creating the smart stuff he's brought to market. He's a sharp dude & does excellent outside the box thinking.

Just for reference in case anybody searches this in the future, here's some typical misinformation from the '84-'89 Carrera Bentley service manual, as well as a photo of the factory '84-'89 911 service manual updates (microfiche- sorry for the crap quality) taken from the page for the Carrera oil system. Bentley shows 188°C (370°F- yikes, who proofread this?) incorrectly/typo and the Porsche service info shows the correct 118°C (244°F) temperature trigger that I mentioned.




I don't know about the 911s earlier than the Carrera, but I do know the Carrera fog lights are fused and relayed. So if you don't use your fog lights (or you eliminated them- i'm admittedly a hater of fog lights) then you can use the existing fog light switch/wiring to trigger your fan whenever you want to. I did this on my former '87 Carrera and it worked fine. Just need to have the main light switch on in order to power the fog lights

^^^^
Here's how I bypassed the main switch/fog light concern.

Easy-peasy...

Best,

Gerry

[KTL]

Originally Posted by 86 911 Targa

^^^^
Here's how I bypassed the main switch/fog light concern.

Easy-peasy...

Best,

Gerry

Thanks for sharing how to eliminate the switching effect of the fog light relay relative to the main headlight switch. You da man Gerry!

[JRSIII]

I have an 88 Carrera with the factory front cooler and fan setup. I too like the idea of adding a switch or something to allow the fan to come on below 240F. I've been reading this and some other posts and trying to study this, and have a few questions. Referring to the attached schematic (thanks Flintstone for this), I'm wondering about the following options:

1) Shown in red. Simply disconnect the thermoswitch and jumper the connector. This seems easiest to me. This of course would result in the fan running all the time. If the car's running, the fans running. Would this work or is this just a bad idea?

2) Shown in green. Again, simply disconnect the thermoswitch and add a manual switch, but use the thermoswitch connector wires. This takes the thermoswitch out of the system, and I'd have to be sure to turn on the fan when needed, but I'm pretty uptight and doubt I'd forget to do this.

3) This is Flintstone's suggestion. I believe the intent here is to allow the thermoswitch circuit to function as normal, but adds an auxiliary switch to allow you to manually kick on the fan when needed. This may be the best option after thinking about it.

Thoughts?

[86 911 Targa]

Originally Posted by JRSIII

I have an 88 Carrera with the factory front cooler and fan setup. I too like the idea of adding a switch or something to allow the fan to come on below 240F. I've been reading this and some other posts and trying to study this, and have a few questions. Referring to the attached schematic (thanks Flintstone for this), I'm wondering about the following options:

1) Shown in red. Simply disconnect the thermoswitch and jumper the connector. This seems easiest to me. This of course would result in the fan running all the time. If the car's running, the fans running. Would this work or is this just a bad idea?

2) Shown in green. Again, simply disconnect the thermoswitch and add a manual switch, but use the thermoswitch connector wires. This takes the thermoswitch out of the system, and I'd have to be sure to turn on the fan when needed, but I'm pretty uptight and doubt I'd forget to do this.

3) This is Flintstone's suggestion. I believe the intent here is to allow the thermoswitch circuit to function as normal, but adds an auxiliary switch to allow you to manually kick on the fan when needed. This may be the best option after thinking about it.

Thoughts?

pm sent.

Gerry