Oil Cooler DIscussion 2021

Mocker · 03-24-2021, 09:07 AM

I need to up my oil cooler game, as my temps climb into unacceptable levels on hot days with the A/C on and in traffic.

I currently have a "passive" center-mounted cooler on my '79 930, which is fine as long as the car's moving. Does anyone have any experience with a modern center-mounted option that is compact enough to fit a couple of small fans behind it, triggered by either a thermostat or the A/C "on" switch?

Our host sells small 6" fans, but I don't think there's enough clearance to install them behind my existing cooler (which is 25+ years old).

One option I'm curious about is this integrated cooler w/fans which is offered by a certain shop in the desert southwest. The core is only 14" wide, so it's considerably smaller than most center-mount coolers, but I'm thinking the increased efficiency with the fans will more than make up for it.
https://patrickmotorsports.com/collections/oil-cooling-and-delivery-system/products/oil-set-fp920m221

The other option is to pull out what I've got and just go with the fender-mounted cooler with a fan/thermostat. I don't think piggy-backing a fender cooler with the center cooler is a good idea, as it's overkill for anything other than the hottest days, and will "over cool" the engine oil on cooler days.

But I'm open to ideas and hearing about what y'all are using, especially those of you using A/C in hot climates.

Andre930 · 03-24-2021, 09:37 AM

Hi,
I have a 934 spec (same sizes) front cooler without any fan and never had problems even in very hot days. I’m in northern Italy.
Before this I had a 3.2 fan installed behind my fender cooler but had not much advantage.

Since I installed the turboS front spoiler and had this cooler costo built and installed, I have no experience of high temperatures.

Unfortunately I have no feedbacks from front-fan cooling solutions.

David · David's Garage

I'm in Houston, have a front mounted cooler and have never had overheating problems when stationary. I figured the cooler could dissipate enough heat all by itself with the engine idling. Or maybe my gauge is bad.

Andre930 · 03-24-2021, 11:53 AM

I forgot to say that when we installed the front cooler the oil capacity was increased of almost 2 lt because of longer tubes and the big cooler.
That is a quite significant amount.

Mocker · 03-24-2021, 01:02 PM

Quote:

Originally Posted by David

I'm in Houston, have a front mounted cooler and have never had overheating problems when stationary. I figured the cooler could dissipate enough heat all by itself with the engine idling. Or maybe my gauge is bad.

"Houston tested" is pretty, pretty good! Unfortunately, I've had a couple of bad experiences, including getting stuck on the highway mid-day last summer in 95 degree weather. Engine quickly got heat soaked and there was no choice but to pull off, and wait in the sweltering heat for it to cool off, which doesn't happen quickly. So I've gotta do something.

Do you happen to know the type/dimensions of your center cooler?

TurboKraft · 02:49 PM

Do you have3 a fender-mounted cooler as well, inline with the front mounted cooler?
And if so, does it have a t-stat mounted fan assembly of good quality (ex: Spal)?

Not had an issue with a single front-mounted cooler, and we make sure to space them off the front bulkhead so there's airflow through it, not just radiant cooling.

Are you confident your external thermostat is opening properly and completely?

Mocker · 03-25-2021, 05:56 AM

Thanks for weighing in, Chris.

I don't have a fender-mounted cooler at all, just the center-mounted one (I believe it's a Ruf), which was installed in the 1990's by the previous owner.

I'm confident that the thermostat is opening, as you can hear when it opens and oil starts flowing. I haven't tested the flow, so I guess its possible it might not be opening completely?

Chris, assuming the thermostat is working and oil circulation is good, would I be "over-cooling" the engine by adding a fan-assisted fender-mounted cooler to my existing setup? The car is not tracked, but is driven.

gsxrken · gsxrken's Garage

How could you overcool if you have working thermostats? The oil won’t go in them.

High temps can also be caused by running too lean, retarded timing, loose fan belt, blocked up cylinder fins, holes in the engine tin or soft seal around the tin. I addressed my tins and saw a small but noticeable drop on the gauge.

TurboKraft · 03-25-2021, 08:17 AM

+1 what Ken said: if the t-stat is working, that will regulate the temperature.
You cannot over-cool these cars. :-)

smurfbus · 03-26-2021, 08:06 AM

Check cold low, warm up on your line at the cooler. Also check the air has a way to get out behind the cooler. I did quick and dirty cut on the bulkhead behind the cooler as the space was minimal. I have hard time fitting the cooler (Brumos full width front oil cooler) with both my front bumpers.

Mocker · 03-26-2021, 09:13 AM

Yeah, I guess I need to buy a handheld infrared thermometer and look at the data.

turbodave930 · turbodave930's Garage

Fitting fans behind the cooler will be impossible. There is so little room behind the front bumper/valence. Adding a fender mounted with fans would solve the problem. Remember, you have an oil thermostat that will ensure that you do not over-cool the oil.

Kraftday · Kraftday's Garage

Kraftday · Kraftday's Garage

Setrab / Mocal / Spa type coolers are fragile when front mounting IMO.
You could mount these Spal type fans and a Setrab COM cooler horizontal with ducting.. if you want to push a custom configuration. RF coolers ran a pull type fan.

The early style coolers and "not good enough" cores lead to the developments with CSF, the 8110 and 8111 coolers are specialized for 911 / 930. Same core size.