Oil temps rising for no reason
 

Hi everyone, this is a little weird and happened over a timeline, but in a nut shell my engine oil temps are far too high for no reason.

My car is turbocharged, built engine 10.5:1 compression and am running 5w40 oil, the story is as follows:

June 2018 -
- Oil temps were okay, maxing 105 degrees celsius on spirited driving

October 2018 -
- Oil temps are now maxing at 117 degrees celsius

January 2019 -
- I installed an oil cooler (MAPerformance)
- Oil temps now maxing at 108c under spirited driving BUT idling at 105 degrees celsius


I don't know at which point it changed, as I monitored every now and then. But 105c at idle with an oil cooler seems too high?

What could have changed mechanically to cause my temps to rise? Water temp fluctuates from 90-98c.

Something must have changed, but nothing was changed by me on purpose.

Thanks everyone

Your idle oil temperature is my normal operating temperature(220f ish) without an oil cooler. Sounds like your thermostatic sandwich plate isn't working correctly, it should open at 85c.

Ambient Air temp ? 117C for a very spirited drive is getting up there, full synth oils can take it but it's warm. Perhaps try another oil.

I rarely, if ever, almost never, get to 220f with just driving around, even in summer. I’m usually at like 180-190f, and all I have is the XT oil cooler.

Does the oil cooler need to be bled or anything like a standard thermostat to remove air trapped against the plate? Seems like that is what is failing. Is there a way to check for oil circulating through the oil cooler? Maybe feel for a hot feed line.

Thanks, I have thought about this, but the fact my temps dropped by over 10 degrees after installing the cooler tells me it might be working or no?

I was thinking 5w40 would be thick enough for this set up, isn’t w50 a little much?

I don’t know if they need to be bled out, but see my reply above regarding the cooler.


Also it’s important to note, if I drive on the freeway and floor it I can get the temp under 100. It just seems to be mostly at idle and city traffic it goes straight to 105-110c.

Oil consumption? Its a built block so maybe oil is not flowing through the block 100% correctly.

At idle, there's no air moving through the cooler, the only benefit at this point is more oil to soak up heat. Once you get moving it should come down a lot, depending on where you have it mounted.

Also, what are you using to measure the oil temp?

@thinkV Was thinking lighter weight oil, heavier weight oil has less capacity to extract heat from the engine so it will run hotter. But if you track it hard then you will want the heavier oil, especially if you live in Brisy where ambient air temps are hotter to start with.


I hear Penrite 10 Tenths is a great oil for heat recovery ;)

It cools down when going quite fast and my oil pressure is high, so I'm not sure that's it but thank you.

Do you think it's a heat soak issue? my downpipe is wrapped but my headers are not. The problem is "when I get moving" it's not going down unless I am going over 100km/h and boosting (boosting brings down the temp a lot) until I come to a stop or traffic.

That's interesting I hadn't thought of that, I'm currently running Valvoline 5w40, will have a look into another oil. My main concern is that when idling at 105-110c my idle oil pressure is like 12psi, it's fine under load.

What does your radiator stack look like? What ordered? Can you try driving with bumper off to see if it's an airflow problem during low speeds?

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Is there any way you can show us pictures of your setup? Honestly to me it sounds like a heatsoak problem, but it'd be easier to identify if we could see some pictures of your setup. Most specifically, if the intercooler is in front of the oil cooler or not. Your headers are definitely going to add heat to the oil pan.

@thinkV


Where in oz are you ? Have you mentioned this to whomever built your engine/setup ? I'd wonder if the thermostat on that oil cooler is opening at or before 85C, would consider testing and/or changing it. I'd bet the Penrite 10Tenths oil of the same weight will help you a lot !


12psi at idle is not a problem (factory rec at least 15psi/1K rpm from memory), my car idles (700-750rpm) at pretty much the same pressure with 0W20, about 95C 18C ambient air ;)

Hi mate, here is a picture of my setup, the stack is
(Rear) Radiator | Intercooler | Oil cooler (front)
https://i.imgur.com/SpdqO1g.jpg


AS above, my intercooler is behind the oil cooler.

Here is a picture of my engine bay:
https://i.imgur.com/Q05Vw3o.jpg

I am in Victoria, but this is occurring on cold nights too (8 degrees, still idle at 105). My idle is 900rpm roughly, with 12-14psi, but this is with 5w40 as well.

I will try penrite at some point, unfortunately I'm bound to Valvoline for the first year with engine builder.

Is there any way to test that the thermostat is working? It should be opening at 85 degrees, but the climb from 85-105 is quite steady. It def dropped my original temps though.

^^ speak to your engine builder but I suspect your turbo would be partly to blame as it's heating the oil especially after a good hard run. When you stop & idle there would be plenty heat soak under the bonnet driving temps up.

Personally I would have ceramic coated the turbo & exhaust manifold inside & out to keep under bonnet temps down. Why the oil restriction ?

This story reminds me of Colin McRaes adventures when he was in the WRC . . . . if he didn't stack it he would often eventually cook his Subaru - Be careful of that oil temp !

I think testing is done in a pot with a thermometer, slowing heating & you should be able to notice the thermostat change position - notice the temp this happens.

ps: I'm in Vic also ;) - cool nights :(