Do I have a thermostat issue?

TheMidnightNarwhal · 01-30-2019, 10:23 PM

So I was talking about oil and temps on another forum and someone made me realise I might have a thermostat issue. Thing is I don't have any codes. I went on a hour drive to test and take some data and looking for more people to chime in.

I started the drive at around 10PM and ended it at around 11PM. Outside temperature was about -17c . Car is a 2011 335is with 102 000KM.

Here is the first part of the trip. I let it idle about 2 minutes then I set off and did city driving. Between 30 to 50 km/h.
https://datazap.me/u/themidnightnarw...ata=2-10-11-12

Then my monitoring stopped for a while so some time passed in between this log and the last one. This log includes faster city driving, 70 km/h and some highway driving. At the end of this log it's about 10:30pm so I did some highway driving for like 10-15 mins. The end of this log shows the start of idling. I decided to let my car idle to see the behavior.
https://datazap.me/u/themidnightnarw...ata=2-10-11-12

The start of this log shows the oil and coolant temp after I have let the car idle for 15 minutes in a parking lot. The coolant and oil temp went up steadily to a good toasty temp. After idling I went onto the highway as you can see. This is where I suspect perhaps my cooling is either to efficient due to a thermostat maybe? Soon as I get on the highway my coolant temps just start to drop steadily. Pointing to coolant being cooled so quickly in the rad.
https://datazap.me/u/themidnightnarw...ata=2-10-11-12

I then end the drive with city driving until I get back home. The temps kinda stayed stable.
https://datazap.me/u/themidnightnarw...ata=2-10-11-12

I read the ECU codes and nothing was listed after the drive.

Anyone wants to chime in?

TheMidnightNarwhal · 01-31-2019, 06:12 AM

Here is another log for just more data.

This is about 8 mins drive on a typical morning for me. It was -18c outside. The oil temp is stupidly maxed out I guess it can't read negative oil temps. Should I avoid dailying my car. Will my engine take a beating and rip for the upcoming 3 years? This is only during winter where it's cold like this.

https://datazap.me/u/themidnightnarw...ata=2-10-11-12

RSL · 01-31-2019, 11:41 AM

Oil temps are not maxed out, that's a signed value treated as unsigned. jyamona or MHD Tuning would need to correct it. Your oil temp is negative there.

TheMidnightNarwhal · 01-31-2019, 11:46 AM

Quote:

Originally Posted by RSL

Oil temps are not maxed out, that's a signed value treated as unsigned. jyamona or MHD Tuning would need to correct it. Your oil temp is negative there.

Ahh ok that's what I thought. But anyways that was just a morning log to see how my temps warm on a cold morning.

The top 4 logs though would you say there is a thermostat issue.

RSL · 01-31-2019, 04:13 PM

I've rarely been in any temps below freezing, but don't particularly think there's something wrong with the thermostat. If the thermostat were actually stuck open, it would take all day to warm up in below freezing ambient.

Except in specific instances, the wax properties alone control the opening/closing of the thermostat and I'd suspect it cracks open (or closes again) at a relatively cool temp, maybe around 38-40C. That means ECT can go that low before the stat fully closes and stops exchanging engine heat through the rad. In other words, that would be the minimum ECT you could expect to see on a properly functioning thermostat. The stat can be forced open (heaters) to reduce ECT lower than the wax's upper temp limit, but there's no way to force it closed to maintain a higher minimum.

If you have the tray off the bottom or cowl out, I'd put them back on to keep as much heat in the engine bay/keep back pressure for air flow through the rad as possible.

I'd probably be more concerned by consistent low temp oil collecting condensation than ECT effecting efficiency, but OTOH, probably thousands of these cars driven below freezing for years by people that don't know more than how to start them and put gas in the tank that are still running.

TheMidnightNarwhal · 01-31-2019, 04:18 PM

Quote:

Originally Posted by RSL

I've rarely been in any temps below freezing, but don't particularly think there's something wrong with the thermostat. If the thermostat were actually stuck open, it would take all day to warm up in below freezing ambient.

Except in specific instances, the wax properties alone control the opening/closing of the thermostat and I'd suspect it cracks open (or closes again) at a relatively cool temp, maybe around 38-40C. That means ECT can go that low before the stat fully closes and stops exchanging engine heat through the rad. In other words, that would be the minimum ECT you could expect to see on a properly functioning thermostat. The stat can be forced open (heaters) to reduce ECT lower than the wax's upper temp limit, but there's no way to force it closed to maintain a higher minimum.

If you have the tray off the bottom or cowl out, I'd put them back on to keep as much heat in the engine bay/keep back pressure for air flow through the rad as possible.

I'd probably be more concerned by consistent low temp oil collecting condensation than ECT effecting efficiency, but OTOH, probably thousands of these cars driven below freezing for years by people that don't know more than how to start them and put gas in the tank that are still running.

Just an update I'm an idiot I was going through my screenshots and I had screenshots the codes 3 days ago and there actually was a thermostat related code that occured about 400KM ago. 2EF4 DME: Map thermostat, mechanism.

So yeah... I was somewhat agreeing with what you said but now that I know there was a code... I dunno.

My coil and underpannel are on. I compared with a another member where his ambient temps are -20and he is able to hit like 90c coolant and oil temps. Me yesterday 1 hour of total driving + idling I was only able to hit 70c for both. And my car was hitting higher temps quicker idling than driving..

RSL · 01-31-2019, 04:42 PM

It warmed up quite a bit in a 10 minute drive, so didn't necessarily think there was a problem, but if there's a code, there's a issue. Maybe it's intermittent.

40-50C is pretty cool, but really not sure what's likely in weather that cold. If others are still 90C in -20F weather, yours is obviously outside that mark and you have a direction to look in.

ore0fllamp · 02-01-2019, 04:13 PM

I literally changed my water pump and thermostat Tuesday with OEM parts, last 2 days here have been around -20C. Coolant was sitting at 100-102C highway cruising around 120km/h for an hour drive. It drops to about 92C-96C when WOT. During a 10 minute idle in -20C my coolant was at about 103-104C. New thermostat is set to open at 97C, I am running 60/40 water/coolant for winter.

I was watching these temp read outs via a ScanGauge2.

Your thermostat is being opened, bad map I guess. If it was stuck closed you would overheat and if it was functioning correctly then you would have no issue achieving the proper temps.

TheMidnightNarwhal · 02-01-2019, 04:44 PM

Quote:

Originally Posted by ore0fllamp

I literally changed my water pump and thermostat Tuesday with OEM parts, last 2 days here have been around -20C. Coolant was sitting at 100-102C highway cruising around 120km/h for an hour drive. It drops to about 92C-96C when WOT. During a 10 minute idle in -20C my coolant was at about 103-104C. New thermostat is set to open at 97C, I am running 60/40 water/coolant for winter.

I was watching these temp read outs via a ScanGauge2.

Your thermostat is being opened, bad map I guess. If it was stuck closed you would overheat and if it was functioning correctly then you would have no issue achieving the proper temps.

Nice OK I think this confirms it then! I am also running 60 coolant / 40 water mix.

That's why I was never able to hit 100c on the highway if you were only hitting 100c on on the highway after an hour.. actually in my case my temp was stable around 45c. I also cruise around 120km/h. And yep, I was able to hit around 90c today because I let it idle in my driveway to see after coming from work!

Were you getting any codes? I only got one 400KM ago and no more. That's the only part I don't understand that no codes.

Anyways I ordered it and I'll still replace it I really hope that's the issue!

RSL · 02-01-2019, 05:34 PM

Other option is that the DME is heating it to open for some reason, potentially as a safety. Hopefully, swapping the stat fixes it.

TheMidnightNarwhal · 02-01-2019, 06:52 PM

Quote:

Originally Posted by RSL

Other option is that the DME is heating it to open for some reason, potentially as a safety. Hopefully, swapping the stat fixes it.

Yeah that's also something I was thinking, since it is electrically controlled.

Any way I could confirm this while waiting delivery, I only be getting it about a week and a half.

RSL · 02-01-2019, 08:07 PM

INPA would be the easiest. Testo would be better and could verify many things at once (ECT at head, ECT at rad, water pump, fan, thermostat heating, cooling mode, etc), but need a laptop and takes some setting up.

TheMidnightNarwhal · 02-01-2019, 08:11 PM

Quote:

Originally Posted by RSL

INPA would be the easiest. Testo would be better and could verify many things at once (ECT at head, ECT at rad, water pump, fan, thermostat heating, cooling mode, etc), but need a laptop and takes some setting up.

I already have ISTA and INPA set up.

But I thought there was only one coolant sensor? I used MHD to log and there was only.

So there's 2?

RSL · 02-01-2019, 08:45 PM

There are hundreds of parameters that can be read from the DME. There's a limit to how many be polled at once, so MHD only has those most useful for tuning/performance monitoring. Yes, there is a coolant temp sensor at the head (MHD logs) and another at the radiator out/thermostat. INPA will show temps at both.

01-30-2019, 10:23 PM	#1
TheMidnightNarwhal Major General 2657 Rep 6,290 Posts Drives: 11' 335is DCT Join Date: Jun 2015 Location: Gatineau, Quebec iTrader: (0)	Do I have a thermostat issue? So I was talking about oil and temps on another forum and someone made me realise I might have a thermostat issue. Thing is I don't have any codes. I went on a hour drive to test and take some data and looking for more people to chime in. I started the drive at around 10PM and ended it at around 11PM. Outside temperature was about -17c . Car is a 2011 335is with 102 000KM. Here is the first part of the trip. I let it idle about 2 minutes then I set off and did city driving. Between 30 to 50 km/h. https://datazap.me/u/themidnightnarw...ata=2-10-11-12 Then my monitoring stopped for a while so some time passed in between this log and the last one. This log includes faster city driving, 70 km/h and some highway driving. At the end of this log it's about 10:30pm so I did some highway driving for like 10-15 mins. The end of this log shows the start of idling. I decided to let my car idle to see the behavior. https://datazap.me/u/themidnightnarw...ata=2-10-11-12 The start of this log shows the oil and coolant temp after I have let the car idle for 15 minutes in a parking lot. The coolant and oil temp went up steadily to a good toasty temp. After idling I went onto the highway as you can see. This is where I suspect perhaps my cooling is either to efficient due to a thermostat maybe? Soon as I get on the highway my coolant temps just start to drop steadily. Pointing to coolant being cooled so quickly in the rad. https://datazap.me/u/themidnightnarw...ata=2-10-11-12 I then end the drive with city driving until I get back home. The temps kinda stayed stable. https://datazap.me/u/themidnightnarw...ata=2-10-11-12 I read the ECU codes and nothing was listed after the drive. Anyone wants to chime in?
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01-31-2019, 06:12 AM	#2
TheMidnightNarwhal Major General 2657 Rep 6,290 Posts Drives: 11' 335is DCT Join Date: Jun 2015 Location: Gatineau, Quebec iTrader: (0)	Here is another log for just more data. This is about 8 mins drive on a typical morning for me. It was -18c outside. The oil temp is stupidly maxed out I guess it can't read negative oil temps. Should I avoid dailying my car. Will my engine take a beating and rip for the upcoming 3 years? This is only during winter where it's cold like this. https://datazap.me/u/themidnightnarw...ata=2-10-11-12
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01-31-2019, 11:41 AM	#3
RSL Captain 647 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	Oil temps are not maxed out, that's a signed value treated as unsigned. jyamona or MHD Tuning would need to correct it. Your oil temp is negative there.
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01-31-2019, 04:13 PM	#5
RSL Captain 647 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	I've rarely been in any temps below freezing, but don't particularly think there's something wrong with the thermostat. If the thermostat were actually stuck open, it would take all day to warm up in below freezing ambient. Except in specific instances, the wax properties alone control the opening/closing of the thermostat and I'd suspect it cracks open (or closes again) at a relatively cool temp, maybe around 38-40C. That means ECT can go that low before the stat fully closes and stops exchanging engine heat through the rad. In other words, that would be the minimum ECT you could expect to see on a properly functioning thermostat. The stat can be forced open (heaters) to reduce ECT lower than the wax's upper temp limit, but there's no way to force it closed to maintain a higher minimum. If you have the tray off the bottom or cowl out, I'd put them back on to keep as much heat in the engine bay/keep back pressure for air flow through the rad as possible. I'd probably be more concerned by consistent low temp oil collecting condensation than ECT effecting efficiency, but OTOH, probably thousands of these cars driven below freezing for years by people that don't know more than how to start them and put gas in the tank that are still running.
	Appreciate 0 Quote

01-31-2019, 04:42 PM	#7
RSL Captain 647 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	It warmed up quite a bit in a 10 minute drive, so didn't necessarily think there was a problem, but if there's a code, there's a issue. Maybe it's intermittent. 40-50C is pretty cool, but really not sure what's likely in weather that cold. If others are still 90C in -20F weather, yours is obviously outside that mark and you have a direction to look in.
	Appreciate 0 Quote

02-01-2019, 04:13 PM	#8
ore0fllamp New Member 5 Rep 16 Posts Drives: e90 Join Date: Nov 2016 Location: North iTrader: (0)	I literally changed my water pump and thermostat Tuesday with OEM parts, last 2 days here have been around -20C. Coolant was sitting at 100-102C highway cruising around 120km/h for an hour drive. It drops to about 92C-96C when WOT. During a 10 minute idle in -20C my coolant was at about 103-104C. New thermostat is set to open at 97C, I am running 60/40 water/coolant for winter. I was watching these temp read outs via a ScanGauge2. Your thermostat is being opened, bad map I guess. If it was stuck closed you would overheat and if it was functioning correctly then you would have no issue achieving the proper temps. Last edited by ore0fllamp; 02-01-2019 at 04:26 PM..
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02-01-2019, 05:34 PM	#10
RSL Captain 647 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	Other option is that the DME is heating it to open for some reason, potentially as a safety. Hopefully, swapping the stat fixes it.
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02-01-2019, 08:07 PM	#12
RSL Captain 647 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	INPA would be the easiest. Testo would be better and could verify many things at once (ECT at head, ECT at rad, water pump, fan, thermostat heating, cooling mode, etc), but need a laptop and takes some setting up.
	Appreciate 0 Quote

02-01-2019, 08:45 PM	#14
RSL Captain 647 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	There are hundreds of parameters that can be read from the DME. There's a limit to how many be polled at once, so MHD only has those most useful for tuning/performance monitoring. Yes, there is a coolant temp sensor at the head (MHD logs) and another at the radiator out/thermostat. INPA will show temps at both.
	Appreciate 0 Quote