Three coolant numbers... 3 different values!


80MPH HWY cruising @2KRpm: COOL OIL !

> If we can trust these numbers we see :
-- the coolant temp is within range
-- the coolant is hotter than oil

Many cars are like that, this is concerning but not alarming.


The oil is cooler than coolant !!
Your oil is currently not removing enough heat so engine is still accumulating extreme heat at driving RPM.

What oil are you running ??
You can easily drop a gear to rev up to 2500.Rpm to allegedly get effective cooling.
You'll then see oil temp get hotter than coolant with core heat removed, heatsoaks canceled.


The temp jerkiness may be due to ECU mapping thermostat opening.
Over heated thermostat may also be sticking to deliver non-smooth operations.
New thermostat is a cheap investment. Steps will still be there but Tstat will be reliable.

 

Based on my empirical data-gatherings, the numeric displayed oil temperature is accurate, whereas the coolant temperature is not. The coolant temperature shows higher than what is reported by the ECU by about 15° to 20°. Therefore, AMG__POWER's oil temperature is quite higher than the actual coolant temperature. Those temps are what I see commonly on my cars and I am running Pennzoil Platinum Euro 5W-40.

 

Here's you go guys. Part 1 was just about the Audi S5 with 75k miles being brought in with misfires. LSPI!

 

Mr. JR: would you pls educate us where is the true coolant temp to look at ?? Help us tie up gaps, we value raw data...

It's too easy to take forged numbers for face value.
(mapped Tstat + salted temps = Amazin'!)

Please help point AMG owners to true actionable data. We honest ppl value what's trustworthy.

We need thruth. It s a big deal if oil above or below coolant. I don't care how little, it has to be ABOVE!!
The Mercedes idiot's gauge keeps misleading many into non-sens - Thank you.

WE CAN'T BASE GOOD DECISIONS ON STUPID NUMBERS... SO I HAD TO CUT THROUGH FLUFF TO PROGRESS but how ?

I used Limits and trends to understand results....
MOD-2.0 : 5w40 noticeably cooler
MOD-2.1 : 6w42 was perfect @550mL
MOD-3.0 : 10w40 more cool ? TBD ?
MOD-3.1 : 11w41 Needs booster shots??
MOD-4.0 : 15w40 OMG or less ??

TO EMPOWER MS! FOCUSED RESEARCH
I GIVE ANYONE WHO MEASURES/CALCULATES ACTUAL STORED PISTONS HEAT VS. RPM/TIME - A FREE ESP SOLDER JOB FOR GDI DRIVEABILITY NIRVANA over true maps.

It's entry level and was free with my single module.
Two more safe but one is for electronic vets


This basic logic on paper is what leads to cheeling with
cool tranny ATF,
quick matched shifts,
razor sharp acc pedal
frigid A/C with cool firewall...
no vaporized burnt oil
AMEN MS!

SOME OLD TIMERS knew viscosity and temps both needed control.
Yours free with gloves on.



+++++ MOD-2.1 "6W42" 5000.Mi oil report....

5360.Mi oil driving up down California HILLS with kickass GDI


old oil as new 5400.Mi: good color + clinginess


cooling well given @600mL booster shots condition

Matched viscosity is my way to remove engine heat effectively with prestine looking oil.

 

COOLANT TEMP - M157

197F = 91.7C The AMG small digital display. The analog needle is also showing approx 90C
The OBD output is showing 210F = 98.9 C

So that means the AMG small display Is also a “doctored” value.
The true correct value is the one from OBD port output.




So now we know...........for certain.

 

> COOLANT TEMPS:
Okay, can we say...
the whole display is manipulated USELESS
we only consider OBD temp data, yes?


> LUBRICANT DATA :
Then what OBD oil sensor/computed data do we have ?

> TESTING :
-- Once we believe oil temps are effective,
we check oil color every 1000.Mi.

-- vaporized/burnt black = extreme heat

-- fair color proves engine parts are temperature controlled.

This requires higher pressures

++++ oil linked to RIP ??
I wonder what is the correlation between Cyl1+5 burning con-rod bearings and them being near the stock pump switched back and forth.
aerated oil
higher pressure
oil contaminants
thermal shocks

 

Well, the engine oil temperature data if M157 should be accurate as it has the B40 triple capability oil sensor.
For non M157 without B40 sensor, it is then the calculated data....where else can it be from, when there is no oil temp sensor to begin with

I can see the oil temp data in Xentry ONLY in the under Full Load test page, as per advice by Jetta.
I think it is more for engineers to test the engine and make sure the oil temperature has to be higher than 60C. since the test is FULL LOAD test p[age.

I did compare the Xentry calculated oil temp data vs my two thermocouple sensors.
Its quite close to the thermocouple I installed on the oil pressure sensor body.

As far as that information goes from Xentry for non M157 engine, it is good enough to know indeed the oil has reached MB recommended oil temperature for the said test.




.
Below is me holding at 4,100 RPM to heat up the coolant and oil.


If the Xentry calculated engine oil temp is before being cooled by oil cooler, it make sense to see it being calculated as hotter than Banks Gauge sensor, at my sensing location.



So now we need a true AMG, which is M157 engine owner who has B40 oil sensor, to test his B40 oil temperature value in Xentry, compared to the mini digital display on I.C.

.

 

So I need a thermostat. I noticed it was slow to warm up (needle really lagging and cluster confirmed). A few days later it finally threw a CEL for it. So now I am amassing $1000 worth of parts because this is a big while-you're-in-there type of job on these (water pump, turbo coolant lines, pulleys, belt, oil cooler gasket, oil filter housing gaskets, various O-rings on everything I touch).





Notice on that second one that it claims to want 221F and despite the thermostat heater being at 100% duty, it can't warm it up. I would like to know where the temp sensor is (is it in the head or is there only one?) but this does tend to suggest that even the M157 is run a lot warmer than the cluster readout (or needle) will admit.

 

The R48 100% duty cycle is actually opposite of the actual value, that 100% means ZERO heater power to R48....if based on my MED 17.7 ECM on my M276.820 engine.
0% of R48 means full power to R48 heating element.
I don't understand why Xentry or the ECM is showing such opposite value.

R48 being powered is for thermostat to open sooner than its mechanical design which is approx 103C / 217F full 100% open and starting to open approx 95C / 203F
R48 is not for heating the coolant, it is to heat up the wax in the thermostat to melt sooner than 95C its starting to-melt temperature.

You can test it using a duty cycle meter at R48 heater element at the thermostat.

The strategy on my engine,which seems to be the same as your M157.


Upon cold start, ECM willl target 105C / 221 F coolant temp. This is a 45C / 113F coolant temp 47 seconds into engine running as per video minutes.
Notice the Xentry showing R48 at 100%..... is actually zero power to the R48 itself. The Fluke 289 DMM is reading actual duty cycle to the R48, which is now NIL, zero.
The Fluke 179 is reading the VOLTAGE applied to R48 by the ECM, which is also at zero Volt.




After a while, 7 minutes later, coolant temp already at 89.25C / 192.65F.... ECM will choose 90C / 194F coolant temp.
Here the ECM is sending 18% duty cycle to the R48 heater ( Fluke 289 ), Xentry is then showing 82% , the opposite value 2nd image below.



....




2.4 Volt is read by DMM under its Voltage menu is a common value when reading pulses of PWM of a duty cycle.
Roughly the calculation as follows : System voltage 14V, get 18% duty cycle, thus 14 x 18% = 2.52 Volt.


...

When engine coolant temp has hit 93.75C / 200.7F, ECM sends full power to R48 and no more PWM pulses. This means ECM wants thermostat to open soon.
That is why the duty cycle meter (Fluke 289 ) also reads ZERO %, because there is no duty cycle pulses anymore, hence see the Fluke 179 at 13.36 volts, full voltage of ECM.
At this point in time, ECM then targets coolant temp to be 80C / 176F.


Video minutes is also the actual engine running time.

.....

The two temperature sensor ( K thermocouple ) brand UNI-T labeled BEFORE and AFTER, is the reading of the coolant hose steel lip temperature. as I want to track coolant temperature INTO and OUT of the radiator.


.




.....
Sensing the R48 heater .







The temperature of coolant IN vs OUT at radiator. 99.6C input, output at 66.8C. But the big radiator fan is at 30% duty cycle only, see 3 in red.




There is only 1 coolant temp in M278 or M157 or M276, take a look at their wiring diagram, easy to confirm, it is called B11/4.
Its just that R48 sitting at a thermostat housing may seems like a temperature sensor


This is M271.8 ( W212 E200/E250 or W204 C250 ). Both the R48 heater and B11/4 ECT is at the thermostat housing





M276.9 3.5NA, M276.8 3.0 Turbo, M278 and M157, same location for B11/4 ECT sensor, at Bank 2 rear azz.






Kev,
It maybe that your thermostat is a little stuck open.


.

 

@CaliBenzDriver my statement concerning the accuracy of the oil temperature display is based on what I measured at the oil pan with my IR thermometers a while back. Not optimal lab environment, but close enuff for government work (I'm a retired government worker, so I know!). The coolant temp seems to be off by about 10%, but the AMG display is always hotter than the ECU reported temp. Again, that confuses me since I doubt there is a direct raw feed to the IC.

Concur @S-Prihadi

 

The 'doctoring' of water temps is pretty common to avoid drivers from calling the dealership when the water temps fluctuate under various driving loads.

My 911 did this as well showing a constant temp under almost all situations. Reprogrammed for a linear response and much happier.

 

I run liquimoly 5w-40 oil, my coolant thermostat ,hoses, water pump and lines are all 19k miles old. I don’t think I have ever seen my oil hotter than coolant, most posts here for the m157 don’t

 

".... but the AMG display is always hotter than the ECU reported temp.... "
Nein Herr JR!
We just got done confirming that IC Temps are useless.

You're still as confused as I was with all the decoys.


only one trusted OBD number .... NOT IC !

True coolant is actually higher... ~210F

The real OBD Temp sensor data is above IC lottery numbers. We only concider the true data because the doctoring is non linear... so meaningless when trying to understand cooling interactions.


> OIL SENSING:
We need a trusted source to evaluate where the oil temp is in relation to coolant temp. I can guess this is OBD PID, a thermocouple probe, IR meter....all except IC.
Everything does not need to be perfectly measured so long we know +/- accuracy margin and it's not fluffy lottery.


At the end of the day, members who want to prevent storing extreme heat, need oil temp above coolant. We've seen there are options to accomplish that including 2750.Rpm.
This is a slow process because of squirters constraints - You're best to tilt the odds in your favor with positive heat removal instead of negative accumulation to extreme levels guaranteed to burn even the best oils.

Best solution has to be practical to be useful.

MOD-0 stock engines hardly see cooling with limited pressure and still work in the way MB designed them.

There's a whole range of cooling with matching results. Again the ECU/TCU are not too friendly with elastic viscosity index. Clutch pressure and VVT position are directly impacted. It works but with degraded performance.


"I don't get this and that with my old oil...."
All individual choices are fine so long expectations match.

We are still sorting out better oil options with all participants.
​​​​​​
I consider prematurely black oil at 2kMi an evidence of extreme heat meaning ineffective heat removal. Burnt oil lubricates with additives package.... ok!


++++ NICE PENNZOIL FORMULA....
How is this good premium oil treating you ?
Danke.

 

We here to help enhance that based on personal preferences.

LM is a very popular advanced oil.

Keep an eye on its color shifting or holding up.
I know you favor a short oil interval which is a great protection.

 

yes sir and thank you guy! How should I go about this as I have ceratec mixed in? I can post some update photos here as I have about 400 miles on it since the oil change

 

Ugh! I'm so dizzy my head is spinning. Like a whirlpool it never ends!

 

agreed! As far as I am concerned the solenoid is a good mod, use a good 5w-40 and do frequent oil changes (5k or less) lol

 

That's it, you got it!

 

I want to post this again. There's some really good info in it, but he makes a couple of statements that make me wonder. One is that thick oil is bad (well, not exactly, but it could be interpreted as that). But I think it was in context of allowing the motor oil to warm to operating temperature before hammering the engine. The other was metal parts (rings) were found in the oil pan and pickup tube from detonation. I never really thought about it, but does the top of the piston go all the way to the bottom of the cylinder, exposing the rings? He did say all DI engines should only use API SP rated oil. Wonder what that means for those of us that had DI engines before API SP was released. Also, he explained that LSPI occurs when unburned fuel mixed with oil in the ring grooves and causes an explosion (detonation). Just looking for comment.

 

Personally I cannot compare the milky shades of Ceratec.

I know JR used to run Ceratec mixed in. I also considered Ceratec before discovering MOD-1.


Establish your base sample COLOR and compare dipstick samples at 500.Mi intervals.

Or use professional oil sampling to witness viscosity droping in the mid W30 range as polymer chains get heat stressed.


Oil will still lubricate safely with its chemical package regardless of viscosity losses.
The cooling will be derated by reduced viscosity.


> GUESSING ON TARGET:
Finding your oil OBD Temp PID can show you live interactions with coolant:

- - Cool black oil + hot coolant == > hot engine
-- Hot clean oil + cool coolant == > cool engine

Cool OIL warmed up by hot COOLANT heat exchanger show limited piston heat removal.

 

@JettaRed here is a link to a dissertation on LSPI (@2020). It is a complex phenomenon described in somehow layman's terms in the literature review, in particular, section 2.6 where a summary table is presented for direct, indirect and "deterrents" influence on LSPI. Interestingly, the author mentions that some additives in the oil can cause LSPI as well as reduce LSPI. If I recall correctly, in one of the LakeSpeed Jr videos, he specifically mentions: calcium, ZZDP, MoDTC, etc. They have to be "tuned" such as achieving a "compromise" between LSPI, fuel economy (losses), and wear. Notice the use of "compromise" -> there is no known solution for the three of them, and we have to live with a compromise: usually fuel-economy dominates because of regulations. If we throw out the regulations, then it is wear vs LSPI (and likely others).

https://cris.brighton.ac.uk/ws/porta...vey_Thesis.pdf

 

Actually Engineering Explained done a good video based on SAE papers of what then becomes SP rated oil. 2 years ago.
The content is very good as it has the SAE test on video.

 

Excellent video!

 

I assume all M157s have the external oil cooler (but certainly my S-model does). This adds a variable so we really can't compare our oil temps to M278/M276 cars in my opinion. I agree, during driving at speed, it's uncommon for the oil temp to be above coolant (at least the coolant reported in the cluster, which is phony and likely showing lower than actual). However, during low speed traffic situations where the external oil cooler doesn't get a lot of air, I will definitely see my oil temps pick up into the 200s. Just remember, in that scenario, you coolant temp may actually be warmer so it is possible your original statement is mostly correct under most circumstances (if we focus on actual temps only).

 

Though a good video, it skimmed on the reasons for LSPI and blurred "conventional knock" into it. Here is from the dissertation: