Oil cooler

[Thom]

Last Summer I installed a Setrab oil cooler twice the size of the cooler supplied with the Kiss oil cooler kit from Lindsey racing but I am not satisfied with the results. Cruising at the lightest load oil temp as measured in the oil sump plug will not go below 95°C, which I think is too high and should go to near 85°C which is the rating of the period 968 oil thermostat currently installed, and that does not vary with ambient temp.
A friend mentioned he installed small fans on the back of the stock oil cooler to compensate for the lack of room to extract air properly, à la 964/993.

The car is so flippin' fast that I luckily always run out of road or sanity to get oil temp anywhere above 105°C on regular road use, but I just thought I would pick the brains of the almighty 951 community to work towards a proper solution as it does not make sense to me to "cook" engine oil whilst merely cruising, even if I know that a high spec full synthetic oil should not be breaking a sweat at anywhere below 100°C.

TIA.

[Tom]

Is it plumbed through a 951 style oil thermostat? Those are (mostly) rated at 95C (or higher), so maybe it's just regulating the temp to its rated temp, and the bigger cooler isn't getting a chance to do it's thing? Or maybe there is an airflow issue? Back in the day, I used to boil those thermostats in a big pot of peanut oil to see if/when they opened. For what it's worth, the normal cruising oil temp on my 992TTS is about 101c.

[Thom]

It is plugged in series with the stock oil cooler and thermostat housing. The thermostat is an 85°C unit as used in period on 968s although all new replacements have been 95°C for 15+ years. I am pretty sure it is functional considering how oil temp increases on the gauge, making somewhat of a halt at around 85°C before resuming climbing up to ~95°C when cruising. I am pretty sure the issue is lack of airflow through the larger oil cooler.

[whalenlg]

It would probably help to use an infrared thermometer to measure to surface temp of the oil lines and oil coolers to see if the oil is flowing through the system when it’s hitting max temps.

[Thom]

Well, this is a good idea, thanks for the suggestion.
I have even been considering investing in an infrared camera as these seem more affordable than ever before. Anyone knowledgeable with these?

[michaelmount123]

Oil cooler installation and effectiveness is not rocket science, but there are certain rules that MUST be followed to get efficient cooling:

1. The air ducted IN to the cooler must be accompanied by a air duct OUT of the cooler. OK, no ducts? Just make sure there is an air path OUT as well as IN. A cooler mounted against a bulkhead is a no-no.

2. Ideally, coolers should fill from the bottom, and exit from the top. This ensures the oil fills the cooler rather than taking a path of least resistance like when both fittings are at the bottom. Second best is to fill and exit from the top. Never (as mentioned) have both fittings at the bottom.

3. There's nothing wrong with 100C temperatures with today's oils. In fact, those temps boil off the condensation that's constantly generated in the oil system.
MM

[blade7]

Around 30 years ago when I used to run VW Golf GTi's, that had an oil temp gauge fitted as standard. I questioned the oil temperature they ran at, And I was told the same thing, that it was to boil off condensation from the oil. And today in my 350 bhp SEAT Cupra, it's reckoned the oil should be at least 90C before using it hard.

[Bergerac]

Well, this is a good idea, thanks for the suggestion.
I have even been considering investing in an infrared camera as these seem more affordable than ever before. Anyone knowledgeable with these?

Fluke make a thermal camera that plugs into your phone, not sure on pricing but it looks amazing

[gruhsy]

Well, this is a good idea, thanks for the suggestion.
I have even been considering investing in an infrared camera as these seem more affordable than ever before. Anyone knowledgeable with these?

Fluke make a thermal camera that plugs into your phone, not sure on pricing but it looks amazing

Thanks for that info about Fluke. I am going to convince my work to get one. All of our multimeters are Fluke along with a bunch of other Fluke stuff.

[Peter Sejersen]

Thanks for adding me to the group. I am struggling to figure out how to take out the 951 oil cooler. As far as I can see I must drain either the cooling water to get the bottom radiator hose out of the war, or I must drain and dismantle parts of the power steering. Both ways are time-consuming and messy.

Are the any shortcuts? Thanks