OldManAndHisCar

I tried to search and got a zillion threads...but. My temps are in general 210-214 and 195-200....why am I thinking that the oil temps were lower before I unplugged the solenoid?

CaliBenzDriver

With improved oil pressure the oil has a chance to transfer heat away from pistons through the coolant heat exchanger while driving. Thus engine oil is going to be hotter than engine coolant.


> Magical "SPRAY RPM" threshold :
-- In MOD1.0 spray RPM is still too high above 2500 Rpm then oil is not sprayed and stays cold just like MOD.0 at normal driving RPM.... not entirely useless but limited use.

Oil still circulates well around the heads to lube HPFP but without spraying heat stays trapped in dry pistons... duh

-- If you want to improve spray cooling at lower driving RPM you need good 5W40 to enter MOD.2.

-- if you want to experiment with old 5kMi oil before replacement... then use small 100ml shots of Mob1:15w50 up to a total near 300ml.

>> MOD2.x helps get the engine temperature well controlled by the smart thermostat to effectively cancels extreme heat soaks: NICE!!

Oil no longer gets burned above 400F and remains around 200F with stable viscosity for VVT/HPFP operations. Big improvement from stock !

-- In stock MOD.0. coolant slowly warms up the oil that is not spraying pistons under 3500.RPM besides few rare events when ECU toggles pump pressure.

The coolant warming the oil is funny because to remove heat it must be the other way around.


> MANUALLY SPRAYING:
You can manually shift down one or two gears to raise engine RPM at cruising speed and SPRAY pistons even with a 0w40 at 2700 RPM.

However the target is not manually cooling the pistons - That is best done automatically with MOD2.1 at normal driving RPM.

The target is solid timings.

OldManAndHisCar

Thank you very much for the great information and taking the time to reply. Makes perfect sense....if I am not mistaken, the two used to always be near each other in temp.

CaliBenzDriver

Yes the oil temp used to trail the coolant by not cooling dry pistons.

Now you have experimental options that can provode actuve spray cooling.

> OIL SPRAY RPM is key:
-- The open question is how much viscosity boost is necessary to spray cool above 1500 RPM?

- MOD1 is definitely not enough!

Try guessing with small 50 or 100ml shots.

M276-NA vaporizes it's oil into smoke when dry-cooled.

a first for my engine: honey oil at 3kMi

Now zero oil consumption, still viscous amber honey after 3000Mi

JettaRed

iTrader: (1)

My oil temps are around 10°F hotter than the coolant. But remember, the oil temperature is calculated and not actually measured. Just like oil pressure, we don't have an oil temp sensor either.

BUT....then why does it change at all? If the oil temperature is calculated using some model based on coolant temp, transmission oil temp, and other mysterious factors, how does unplugging make a difference.

Still, I agree with @CaliBenzDriver logic that more heat is now transferred to oil from the pistons than before.

I have also noticed that my (calculated) oil temp is a little higher (~5°F) since I switched to the Pennzoil Platinum Euro 5W-40. Again, how does that affect the calculated oil temp?

CaliBenzDriver

I have no exposure to the computed oil temp. Yet if we judge fake oil temp with what we know about the fake coolant temp ... then we stay away from heavily salted ECU numbers.

Even cars equipped with proper sensors don't display true sensor to conceal extreme dry-lube heat. You need to read ECU PID's over CAN-D.

I really wish we could get both oil pressure and temperatures. Then we would know at what pressure oil begins to pick up piston heat.

We know pressure is around 25PSI and by the time the squirter effectively reaches pistons it's near 30PSI....


PPL on MOD2.0 5W-40 squirting ROM is a bit above 2100.RPM due to hot/cold viscosity changes.

TomZVB

Cruising, my oil temp (AMG) tends to stay close to the coolant temp. If I’m on it good, temps will raise but easy cruising aligns them pretty close.

OldManAndHisCar

After some - shall we say - less than frugal driving....seems odd to be a 20f separation, maybe I am nuts.

W205C43PFL

Well, is the engine bay less toasty when you pop the hood after a spirted drive? Like is your garage no longer an oven? Unplugging the oil pump solenoid keeps things cooled in general.

OldManAndHisCar

I seriously installed fans in my garage and one in the peak venting out....two of these.....so, I dunno.... ;-) We have to cars with a total of 16cyl and four turbos in this garage....

https://quietcoolsystems.com/attic-f...le-attic-fans/

W205C43PFL

Haha nice : )

TomZVB

The pistons are being cooled all the time now vs only when the ECU calls for it based on condition so an increase in oil temperature is expected. Running at 215-220F is not a problem for motor oil. In fact, a good byproduct of the higher heat is you'll be boiling out water contamination that may otherwise stay in the oil. Temp in the 230-240 range is nothing for a modern synthetic oil - I wouldn't at all be concerned. Really beating on the car would show more - even then, not an issue.

JettaRed

iTrader: (1)

No one is going to argue with that.

JettaRed

iTrader: (1)

My temps are actually a little higher after switching to 5W-40 from 0W-40. Still, I would not fret over those temps. Does the engine oil temp come down with frugal driving?

Mojo20032004

Mine are also slightly higher with more aggressive driving. Usually 205-210 range depending on outside temps.. Cools down after a few mins of cruising.

CaliBenzDriver

With MB introducing curve ***** all over the place it's not obvious to understand the meaning of mapped sensor data.

We have the massaged coolant gauge in Celcius!
IC Display 197F coolant + 215F oil
Eng. tachometer 1200.RPM
Tranny in 7th Gear at 50MPH...


Coolant °C + Oil°F + Coolt°F + RPM

> What is happening???
-- We are cruising with a hot engine
-- Whe ECU has opened Tstat for more radiator cooling as witnessed by temps shown as 90°C.
-- the coolant is well cooled
-- the oil is loaded with engine heat being exchanged with coolant


> EASY TIP:
We note the cruising at 1200.RPM may effectively not spray dry-pistons.

Set tranny to "Sport" mode or manually drop a gear or two to raise RPM in the range of spray RPM and bump heat-exchanger circulation.

You then will be removing more heat from a hotter oil and cooler pistons.

As noted the compounded the net result in when you park in the garage or get stuck in idle traffic, your new engine temp is NORMAL & 200F COOL... instead barbecue griddle


> Questions:
How many Miles on what MOD level?

Do you want to trigger an ECU/TCU relearn?

CaliBenzDriver

JR: this is exactly what we are after.


The difference between the two oil viscosity is only the spray RPM:
A fraction more viscosity > lower spray-RPM > hotter oil > Cooler pistons > cooler engine > stable viscosity > rich ECU Maps > balanced cylinders = more power to you!

CaliBenzDriver

I totally ignore the oil tstat. I trust they are built to require service... at what mileage do you need to renew it

If we observe oil discrepancies between similar engines some exchanging oil heat better than higher mileage then it will be a clue for hardly moving oil tstat. Not all engine have them.

PeterUbers

A few hundred miles after disconnect, no significant change in reported oil temp on dash compared to pre disconnect in similar weather. Stop and go traffic, 100 octane tune, I do have my fan set higher in my 100 octane tune, however. 0w-40 OEM Mobil 1

Car drives exactly the same - no significant perceived changes for this driver

JettaRed

iTrader: (1)

Yep, those look close to mine.

OldManAndHisCar

Mine are always further apart. I have Amsoil 5-40 in the engine...but, as we all know, no real thermometer in there...I wonder how my car is coming up with the 20 degree variance....and, why.....

Mojo20032004

What about 2 back to back pulls 2nd into 3rd? In theory oil temp temp should increase due to parts moving faster internally

PeterUbers

im sure it'll bump to 220F... no doubts ... just saying that the oil temps for me are identical behavior to pre pull. I'm not sure what the higher fan setting does for temps empirically and I don't have the IAT mod currently switched on

Mojo20032004

​​​​​​According to my datalogger gauge, the fans kick on when the car temp reach 220*,but the cluster will only show 199-200 when this happens

PeterUbers

good info