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My OBD Fusion lists just generic OBD2 parameters (SAE parameters?). I don't see any BMW-specific parameters like the CTS temperature in any of the menus, let alone the HEATED THERMOSTAT PULSEWIDTH PID.

That is why my data only shows coolant temperature (which I am sure is the ECT temperature) and intake air temperature.

Can OBD Fusion log the Heated Thermostat Pulsewidth PID?

Can OBD Fusion log the CTS temperature?

If so, I would be interested in knowing how.
A few things to answer some of your questions and also note some things for others that may run across this thread in the future.

If someone is considering the OBDLink interfaces, I would spend the additional money on the OBDLinkMX+ because this interface supports Enhanced code/data support for selected models. I believe the MX+ interface is about $20 more then the MX interface and the MX+ interface should also work with iProducts.

Anyone that purchases an OBDLink interface DOES NOT need to purchase the OBDFusion App. OBDLink has OBDFusion provide the OBDLink App as an OEM App for Free. The OBDLink App ONLY works with the OBDLink interfaces.

At this time NEITHER OBDFusion or the OBDLink App provide Enhance code/data support for BMW or the German manufacturers that I am aware of. The cost of Licensing this data is very expensive and at least for the short term the OBDFusion/OBDLink suppliers have not chosen to invest the capital for the Licencing for the German brands. OBDFusion AND OBDLink do offer Enhanced code/data support for an additional In App purchase.

OBD Fusion now supports Enhanced diagnostics for Ford, Lincoln, Mercury, Mazda, Toyota, Lexus, Scion, Nissan and Infiniti vehicles. Enhanced diagnostics provide access to additional modules such as ABS, Airbag, Transmission, 4x4, and Body Control modules. You also get access to hundreds of additional parameters that are not available over standard OBD2. Enhanced diagnostics are available through an In-App Purchase in OBD Fusion.

When using the OBDLinkMX+interface AND the free OBDLink App there is Enhance code/data support for the above vehicles manufacturers as I recall with the addition of a subset of GM years and vehicles. When using the OBDLinkMX+ interface and OBDLink App I believe the Enhance code/data support is included, but this should be verified with the OBDLink provider.

As for question can OBDFusion Log the following information:

Can OBD Fusion log the Heated Thermostat Pulsewidth PID?

Can OBD Fusion log the CTS temperature?

Not natively, OBDFusion is a generic OBDII App. It may be able to Log these items using the "Custom PID" feature if you can figure out the PID values and PID calculations required. I not bothered to spend the time to try this and my E46 is 1100 miles away from me and I rarely see if these days.
 

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BaliDawg, thank you for pointing out the availability of Android E46 dongle for Carly. I went ahead and ordered it just now.

It does appear that I have to order a separate "Additional Plug for Android" which I can only find on ebay, to be shipped from England. Yes, I just ordered that also.

JFOJ, thank you for helping me navigate through the thicket of OBD2 apps. I have only been getting by using INPA with a Windows XP laptop.


Now, here is the graph of the log that BMWNorth initially posted in his first post:



I don't know... It just seems like in this instance, the thermostat had an operating temperature of about 90C.

In every one of the instances shown in this discussion, I can discern one specific temperature at which the particular thermostat settles into a steady state.

Why do we have several different temperatures for that steady state?

ADDENDUM:

This article on thermostat failure modes may have some answers that I was looking for. The thermostats that they discuss here pertain to Bentley, not BMW, but I think the issues apply to BMW in some ways also.

The article says the most common failure mode for thermostats is not closing all the way, being stuck partially open, so to speak. I don't know if this applies to BMW thermostats.

The article does mention boiling water test as a valid method of testing the opening temperature of the a thermostat.

Also, the article points out that there is a wide variations in the opening temperature of supposedly identical thermostats (in this case for Bentley) and that one thermostat opened 8F below nominal temperature when tested.

The testing method? The "boiling water" test where the temperature of the pot of water is gradually changed to see when the valve opens.

Interestingly, the article states that in their testing, the same thermostat would always open at the same temperature in boiling test.

I have no experience with aged BMW thermostats. When I got my 2002 325i 2 years ago, I replaced everything that I thought could break in the future with new genuine BMW parts, including the thermostat.

I was hoping to limit the discussion to a properly functioning cooling system that behaves as it did right out of the factory as intended by the BMW engineers. But if we are gonna talk about how the cooling system misbehaves with age, or due to manufacturing variations (being off-spec), etc, we might as well get that discussion out on the table.
 

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JFOJ, thank you for helping me navigate through the thicket of OBD2 apps. I have only been getting by using INPA with a Windows XP laptop.
While INPA has its merits, it is not the tool for Driveability, generic OBDII is far superior IMHO. People here and all over the Internet seem to think you can only troubleshoot and fix cars with factory software, not true with OBDII controlling the engine fuel systems.

One thing I forgot to add, you NEED to downloand and install the OBDLink App on your Android device because it is REQUIRED in order for Firmware updates to be pushed to the OBDLink interfaces. Install OBDLink and see if there are any Firmware updates for the OBDLinkMX interface.
 

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BaliDawg, thank you for pointing out the availability of Android E46 dongle for Carly. I went ahead and ordered it just now.
If you already have a WiFi or BT OBD interface and you***8217;re willing to open it up, it might be worth it to internally connect pin 8 to pin 7 and see if the Carly app can then access the other modules besides DME and EGS. I believe it only supports LCM and GM5. Always wondered what was different with their own OBD interface and it might be as simple as briging pin 8 to pin 7?
 

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If you already have a WiFi or BT OBD interface and you***8217;re willing to open it up, it might be worth it to internally connect pin 8 to pin 7 and see if the Carly app can then access the other modules besides DME and EGS. I believe it only supports LCM and GM5. Always wondered what was different with their own OBD interface and it might be as simple as briging pin 8 to pin 7?
That’s probably part of it, but I bet they have some custom firmware that tells Carly it’s an official interface
 

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2) My thermostat did open up when I decided to idle in my driveway for a few minutes at the end. I believe the DME actually commanded the thermostat to open rather than it opening 'naturally'. Notice when the radiator temp hits 84.5, the temperature falls (indicating the thermostat closed), and then starts rising back up again a bit below 60ºC.

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I think it started falling after hitting 84.5 by the fan turned on (fast falling slope compare to slower rising by opened tstat)

BMWnorth has a tstat that opened at lower temperature than Bmw spec. This the reason why the engine temp rarely reached 90C, while most E46 held steady around 93. If he said his tstat was 97 rated, then we like to see it verified in hot water with a thermometer.
 

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I finally got everything I need to run Carly on my BMW.

I recorded the ECT temperature, CTS temperature, and the oil temperature while warming up my car in the garage.

The graph above shows that the ECT eventually reaches 97.5C, and that the thermostat only opens once the ECT reaches around 97C.

Below 97C ECT temperature, the thermostat is closed.

Outside temperature is -6F, and in the garage, it is 0F.
 

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At emineid. Good info. I’ve been wondering for a while now about oil temps. I don’t monitor them in my 330. So I was wondering at what point I’m ok to go to the full 6700 rpm. Looks like a rule of thumb is to hit full engine operating temp which we can see via on board electronic readout. Then + 5-7 min to be in the 170-180 deg f range. Then we are good to blast it. What do y’all think safe oil temp is for higher rpm driving?


Sent from my iPhone using E46Fanatics
 

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Ideally g he oil should be higher than 100C. Most experts say it should be within 230 - 260F. The graph didn't record long enough to show the final stabilized oil temperature. I don't know if the car has an oil thermostat to control this.
 

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// Quandt AG (Retired) //
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Discussion Starter #110 (Edited)
The graph above shows that the ECT eventually reaches 97.5C, and that the thermostat only opens once the ECT reaches around 97C.

Below 97C ECT temperature, the thermostat is closed.

Outside temperature is -6F, and in the garage, it is 0F.
Dropped in to check pms. What rubbish. Did no one read the posts. The tstat in the car I was posting was an oe Wahler 97C.

If what you are saying is meant to be true across this whole platform then there is a simple test anyone can do without logging. Shut off your car before it gets to 97c. If what you are saying is true then the lower rad hose will be cold. Anyone can try that, no special tools required.

If what you were saying were true then two items need explained:

1. The thermostat would not open fully (conventionally) until 105-107C - don***8217;t you think that***8217;s a little high? (You might have to research how long it takes the wax expansion to actually overcome the spring. Try Stant or IGI - makers of wax motors. - Don't forget the 5C hysteresis function that will keep the tstat open to lower temps from thermal inertia and friction.)

2. Why are lower rad hoses hot before 97C. Hell I***8217;ve seen them hot at 90C.

But it will be real simple to disprove. Don***8217;t let your car get to 97C ECT. Your rad hose must be cold if the thermostat has not STARTED to open. Be interesting to see what folk find.


BTW - saw your video on youtube, what you believe to be the DME controlling your thermostat - the flashing LED every couple of secs (while the video shows your motor temp at below 40C) is actually DME maintaining communications with the thermostat - not opening it.


Watch the videos:


The BMW referenced engine (M52/54) has limited control of coolant flow since it employs an RPM dependent water pump. For a better understanding of how this thermostat typically operates in a working engine using the same configuration as the M52/54 see the MAHLE-Behr video. Note at approx 1:40 time stamp the modulating action to the two coolant loops. https://youtu.be/_HclvBmwWgQ

This video also by MAHLE-Behr shows how the ECU map control is activated to divert all coolant through the radiator loop, then returns to normal once the high load condition is absent. https://youtu.be/ruHGm4iSC_A


https://youtu.be/0ZWcTHY2T0U
 

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1. The thermostat would not open fully (conventionally) until 105-107C - don't you think that's a little high?
That's actually pretty typical for MAP controlled thermostats. M62 and N5x won't open until ~115ºC without DME influence. M54 opens up a bit earlier, but not anything near 80ºC, I'm pretty confident about that.
 

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"If what you are saying is meant to be true across this whole platform then there is a simple test anyone can do without logging. Shut off your car before it gets to 97c. If what you are saying is true then the lower rad hose will be cold. Anyone can try that, no special tools required."

I am not sure why you didn't just look at my CTS temperature curve.

See the temperature curves above. This is from this morning. I had my hand on the lower radiator hose every minute or so to feel how cold or warm it is.

I warmed up the BMW in my garage. I kept touching the lower radiator hose to verify that it stayed COLD right up until the ECT reached 97.5C. The lower radiator hose remained cold at ECT 97.5C for a few minutes until it started feeling warm and then hot. The CTS temperature corresponded with what I felt. The CTS temperature was below 0C until it started going up after a few minutes of ECT at 97.5C.





"BTW - saw your video on youtube, what you believe to be the DME controlling your thermostat - the flashing LED every couple of secs (while the video shows your motor temp at below 40C) is actually DME maintaining communications with the thermostat - not opening it."

I explained clearly that the flashing LED was when the DME checks to make sure connection is intact to the thermostat. I explained clearly that the DME actually activates the heater when you see the LED stay ON for about 3 seconds or so. This is clearly seen at 13:04 time mark on my youtube video as I had explained. And also, I showed on my temperature curve in an earlier post with arrows when the DME actually activates the thermostat heater. I am not sure why you glossed over this explanation.





"1. The thermostat would not open fully (conventionally) until 105-107C - don't you think that's a little high? (You might have to research how long it takes the wax expansion to actually overcome the spring. Try Stant or IGI - makers of wax motors. - Don't forget the 5C hysteresis function that will keep the tstat open to lower temps from thermal inertia and friction.)"

In fact, it's even more dramatic. The thermostat opens more or less fully by 100-101C. How long does the wax expansion take to overcome the spring? It depends on the temperature gradient. Going from 97C to 100C (if the coolant temperature were to change instantaneously--a theoretical circumstance) takes a few dozen seconds, less than a minute.



"2. Why are lower rad hoses hot before 97C. Hell I've seen them hot at 90C."


This is a good question. Why does YOUR CAR do this? My car does not do this at all. On my car, the radiator hose stays cold until ECT is 97.5C*. (*Caveat: This is unless the MAP thermostat heater had been activated. For this discussion, we are talking about conditions where the MAP heater has not been activated.)




As far as your experiment with the thermostat heater in your video, there are several things that are wrong with it.

First, you do not have the spring in place. This is an error. The wax element needs the spring force pushing against it to work as per specification. You may have seen experiments on the youtube by others who did basically what you have done, and in those instances, the piston actually flies out of the wax housing like a bullet. This goes to show that there may be some vapor pressure that developed (formation of gas) rather than strictly solid-to-liquid phase transformation.

Second, the way you read the temperature with an IR meter is suspect. The correct way of reading the temperature is to suspend the thermostat in a pot of water with controlled temperature.

The fact that you so distrust the hot water thermostat testing method is the core problem why you misunderstand how the thermostat really behaves. There is a nice SAE paper that describes how they test the thermostat wax in lab setting. It is to take 2 pots of water, each at a different temperature. They take the thermostat from 1 pot to the next, and measure the change in the valve opening and also the time it takes. They do it for several temperature gradients, going from colder to hotter, and from hotter to colder.



So to sum up:

1. On my car, the thermostat stays closed until 97C or so, and it even remains closed for a few minutes at that temp. I am not sure why the thermostat behavior is different in your car(s).

2. The thermostat heater is activated (heated) when the 12V signal from the DME lasts about 3 seconds. The pulses (<0.5 second) you see in my LED does not reflect the heater being activated, and I had explained that clearly in my posts.

3. Hot water test is the way to go. You can do what SAE engineers do, get 2 pots of water at 2 different temperatures, and take the thermostat from 1 pot (after it had reached equilibrium with the water temperature) and take it to the second pot and observe the change in the valve opening. You can even use 50:50 coolant to be able to perform tests at temperatures higher than 100C.

Or, you can send me the thermostats with known behavior in the car, and I would be happy to perform this test for you. This test has the potential to solve some of the mysteries you are encountering.


ADDENDUM:

I was looking at the graph of your logs, BMWNorth, and I am noting that the CTS temperature is HIGHER than the ECT temperature at times. Why is this? How can the CTS temperature be HIGHER than the ECT temperature? I do not see that behavior on my graphs. Is it possible that your ECT temperature reading is off?
 

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I was looking at the graph of your logs, BMWNorth, and I am noting that the CTS temperature is HIGHER than the ECT temperature at times. Why is this? How can the CTS temperature be HIGHER than the ECT temperature? I do not see that behavior on my graphs. Is it possible that your ECT temperature reading is off?
I mentioned this before, but the only thing that makes sense to me is if his automatic transmission is running hot and is requesting the DME open the thermostat.

I also need to look into those Euro DME tunes to see if they have any different thresholds.
 

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Discussion Starter #114
ON those occasions where CTS exceeded ECT note both speed and RPMS. Speed = 0 (no air cooling) RPM was quickly punched very high - So what does an RPM dependent water-pump do? It quickly moves the hot coolant out of the engine and out thru the radiator loop (the engine loop is closed by the bypass valve at that point) . You can manipulate this (as I did while idling) if you wait till the right movement you replace all the hot coolant in the engine (if your waterpump is working well) with coolant that has just been cooled through the rad. So for a brief moment you will have a higher temp at the CTS than ECT - wouldn't happen driving. One of the reasons for switching to electric pumps, to prevent over cooling.

Again if what you are saying is true - that the thermostat cannot open before 97C. Then the lower rad hoses will always be cold until that happens. I have owned 5 e46's - never had one that regularly got above 95C - so you are saying they never opened? In summer they run around 91-94C in winter they are running 89-92C - everyone of them had a hot lower rad hose before 97C.


Maybe not on an n52/54 but I'd be panicking if my normal temps were running 97-107C in this engine - Those high temps also don't seem to correspond with what we do know about the fan temps ON @ 85C off @ 80C.

Like I said easy enough test - according to your test on your car your rad hose can't be hot till your ECT is 97 or higher - just don't think that is true. Hasn't been on any of mine.

 

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Keep in mind the fan is controlled based on coolant outlet temperature, not motor temperature. Keeping the radiator at <85ºC doesn't conflict with a motor temperature being higher than that.

Also on the M3, the electric fan turns on at 50ºC radiator outlet. The target temperature in that car is definitely not 50ºC.
 

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BMW-North's video showing the IR temperature meter reading the body of the naked electric heated wax motor cannot be used as a proof, because it could have multiple flaws.
1) The IR temperature meter is not a reliable instrument - it depends so much on the surface texture.
2) The wax was heated internally by the heater resistor, and the meter was measuring the outside package exposed to ambient cool air, and there is temperature gradients from hot inside to cooler outside.
3) Without a loading spring, any gas inside could easily expand and started pushing the rod out (instead of gas being compressed by the spring) before the wax changed to liquid.

why don't you cook a whole Tstat in a larger pot of water with a standard glass bulb thermometer and video the test? The water measured temperature is the SAME as the internal wax temperature. Why keep dogging around this simple test? To verify a thermostat, most engineers would have no problem with the idea of heating it in water instead of install it in a car, and then read the DME sensor data or feeling the lower hose with running engine.
 

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I got testo to log what I wanted. Here's my data. Car was just idling, so I didn't bother charting RPM



Very similar to emineid's data

Notes:
The DME never commanded the thermostat open
-There was a small blip to 3% shortly after I started the engine. I suspect that***8217;s the DME just doing a startup check.
Thermostat opened up on its own around 95-96ºC - a little lower than emineids, but I'd call that margin of error
Electric fan "rests" at 5% PWM, but I verified the blades are not spinning at that duty cycle.
Electric fan kicks in when TCO_EX hit ~85ºC. Temperature drops to about ~60ºC before rising back up
I physically touched the lower hose when the motor temperature was around 92ºC - it was cold to the touch.
Max motor temperature was 96.75ºC
 

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The same level of curiosity as myself it seems.

1. The temp never reached 97C during the entire test cycle - During the test cycle is the thermostat ever open or always closed? How can you prove it?

I monitored my coolant temp after the full overhaul and it tops out at 98C with a 97C tstat. If you open the hood you can feel the radiator. Mine was warm to the touch at the top but cold generally all the way to the bottom. (Yes. It was fully bled). Which seems to me that the tstat is only slightly open which is what you would expect from a 97C tstat at 98C. I monitored it every time I went out for over a week using the hidden OBD funtions of teh display unit. This is why I began wondered about the 85C tstat that is available. The viability of installing it instead of the 97C.

2. At what threshold and what parameter decided to signal DME to activate the electric fan? Was the DME decision impacted by the temp at ECT or oil temp? How can you prove that?

Good question. I replaced the fan with brand new. Not seen it come on yet. New sensor in the bottom hose too.

3. At what threshold and what parameter decided to signal the electric fan to shut-off. Was that DME decision impacted by ECT or oil temp? How can you prove that?

No idea. But would like to know.

I was gonna add a 4th question regarding the t-stat heater voltage but it would have been a trick question as it was never active during the test cycle as verified by the live data so I just dropped that column.

I don't know what the book says but I put 12 volts across the terminals and it took 2 min 30 sec to fully open the the tstat. Went back to the closed position just as quickly. As for what run time conditions need to exist to make that happen I don't know.

As suggested above it may have to do with more than temperature. Engine speed for example might cause the DME to open up the tstat to allow coolant to pass through the radiator. This may have an impact on system pressure I guess by increasing volume accessible to the coolant. But I doubt it.
What I can say is that if the tstat is already fully open, because you have put in an 85C stat instead of a 97C tstat, then that's unlikely to be affected by the move.

It would be nice to have answers.
 

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RayPooley:

I have an indicator LED light connected to the 12 volt wire to the thermostat.

Here is what I observe while driving:

Often-times, all it takes to get the LED light to come on is a moderate stab of the gas pedal. Meaning, increased "engine load" causes the DME to send a signal to the thermostat to heat it up.

Did you try to hook up the 12V signal to the thermostat on a "benchtop" setting?

Because during driving, the thermostat is already at or near 97C. You are not heating up the wax from room temperature. It does not take more than about 10-15 seconds or so for the thermostat to open up more when the 12V signal is sent to the thermostat. You can tell, because just a few seconds after the LED light indicator turns on (3-5 seconds on, then off), you can see the ECT temperature plummet, sometimes down to 84C.

If the LED light is on for only 2 seconds or so, the ECT goes to maybe 93C.

If the LED light is on for 4 or 5 seconds, the ECT goes to mid-80sC

These numbers are all rough estimates.



By the way, the DME always sends 12V signal to the thermostat ALL THE TIME while engine is on. But for the vast majority of the time, the signal is just a fraction of a second every second or so, and this is not long enough to heat up the wax much at all, so it has no effect on the thermostat opening.

But, if the 12V signal is 2 seconds, or 3 seconds, or 5 seconds, the wax gets heated above 97C and the thermostat opens up more. That is when you see the ECT temperature plummet.

Then the ECT temperature gradually returns to the 97C or so, as long as DME does not command the thermostat to open more again.

By the way, OBD2 tools DO NOT show when the thermostat heater is activated!!! The so-called "THERMOSTAT PWM" does NOT show any activity even when the DME sends a several-second-long 12V signal to the thermostat. At any rate, the E46 does not use pulse width modulation. There are other BMW's that use PWM signal to the thermostat.


So the bottom line is that the MAP thermostat is a very crude way to have a thermostat that works at 97C or so for the most part (low load) but acts as a lower-temperature thermostat at higher loads. The "lower temperature" can be anywhere from 84C to 90C to 93C. It all depends on how long the 12V signal is sent to the thermostat (typically 2-5 seconds).


The DME has some algorithms that make it somewhat difficult to predict mentally when the MAP thermostat is activated. Sometimes, I can drive 45 minutes and never see the MAP activated (my 12V LED indicator). Other times, I can see the LED light up almost every time I accelerate from a stop or go up hill and jab the gas pedal a little bit more.


Here is what the E46 ECT temperature behavior looks like, then, on a typical drive.


Turn on engine---ECT goes from ambient temperature (say 20C) to 97C over a few minutes of driving.

Go up hill and jab on the pedal: 12V signal goes to the MAP thermostat for about 2 seconds, say, and the ECT temperature drops from 97C to 92C, say, over about 20 seconds.

Gradually, the ECT climbs back up 97C.

ECT stays at 97C for a while.

Hit the gas pedal again, hard, and the MAP lights up for 4 seconds. ECT goes to 86C over about 20 seconds.

Gradually, the ECT goes to 97C.

Drive really hard uphill, and the ECT goes to 100C. MAP lights up for 4 seconds. ECT goes to 86C.

ECT gradually goes back to 97C and stays there.

For the most part with normal driving, the ECT will stay at 97C with dips to 84C or 88C or 93C or anywhere in that range everytime the DME decides to (mainly when you step on the gas pedal hard).


So from my observations, I would make a personal guess that the so-called "low temperature thermostat" that people talk about is not useful for the E46 BMW. The reason is that when the engine is making a lot of heat suddenly (gas pedal pressed hard), the thermostat becomes a "low temperature thermostat" very quickly (within about 20 seconds) anyway. At part-throttle (low load, not pressing the gas pedal hard), the thermostat is at 97C or so, and you are not making that much heat that would damage the valve seats, etc. So you already get the benefit of a low-temperature thermostat WHEN YOU NEED IT if you have a MAP thermostat.



Just one more observation which has nothing to do with the above discussion: The 1.4 bar pressure cap that they market for the BMW (instead of the 2.0 bar cap from the factory) is a waste of money. I have a coolant pressure gauge connected to the upper radiator hose by the expansion tank. The pressure virtually never exceeds 1.2 - 1.3 bar during normal driving. Caveat: If I deliberately fill the expansion tank almost full (way above what I am supposed to), then the pressure does climb to 2.0 bar. So if you fill the tank as you should, you don't get any benefit from the 1.4 bar cap.
 

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Emineid, I don't feel like responding to the post line by line, but the DME absolutely does use PWM. There's a map that correlates what duty cycle is necessary to attain X temperature opening. And in fact, you can hard code a desired PWM setting to override the map control of the thermostat altogether. A 12v indicator won't be as reliable for a PWM controlled function.

I've since sold my 330i and have no plans to ever own an M54 car again, so I can no longer experiment.
 
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