Thermostat Soft-Failed at 85k - Do I need to replace other parts?

[Len]

Hi,

Somehow it's taken until Dec for it to start getting consistently cold here. I've been noticing my temp gauge not getting up to the center line every now and then (weather would randomly get hot and cold so it wasn't consistently below temp). Today I finally opened the test menu and went on my morning commute (about 15 min - 2-3 min street, 7-8 min highway, 3-4 min in traffic on a congested 2 lane road). Temp only barely got to 62 C and that was after I parked! Planning to replace the tstat since most threads here say it's not too bad of a job, but at 85k miles is it worth doing the other "while I'm in there" items or could I get away with just the tstat? It recently became my daily so trying to shorten the amount of time it spends taken apart.

Thanks!

[Effduration]

I'd do the water pump if original...and I would squeeze upper and lower rad hoses..if they are pillow-ey soft, I would replace them...

[andrewwynn]

Originally Posted by Effduration

I'd do the water pump if original...and I would squeeze upper and lower rad hoses..if they are pillow-ey soft, I would replace them...

That's an interesting way to diagnose. Depends a lot on temperature.

[nick325xit 5spd]

What is the age of your cooling system generally?

2004 was a long time ago and rubber and plastic wear out.

[oldskewel]

I'd be more concerned about the hoses (good point about the plastic hose ends being a concern as well as the rubber - on my 3.0i's upper radiator hose, it was the plastic end near the radiator that failed first, at around 180k miles) than the thermostat. And it sounds like if anything, the thermostat failure mode is that it sticks open, which is not going to blow anything up.

But on the thermostat, does anyone have a good number on what the resistance of the heating element should be? My 2001 3.0i has a 50k-mile old, dealer-installed Genuine BMW thermostat, and I don't have an OBD code or engine light, but ...

Recently I've been getting the following code on my Foxwell:
1-DME, 7B DME: Activation, map cooling
Looking that up gives reports of it being the thermostat heating element. I measured the resistance of my heating element as 3.7 Ohms, which seems in the right ballpark, but am wondering if it is in spec.

OP, related to this, have you measured your thermostat heater resistance? Scanner info (note that I have no issues I can see other than that code which only appears in the Foxwell BMW diagnostics)? Have you tried leaving the connector unplugged to see if your engine runs hotter? Suggested for debugging, not as the solution.

[RocketyMan]

Originally Posted by oldskewel

I'd be more concerned about the hoses (good point about the plastic hose ends being a concern as well as the rubber - on my 3.0i's upper radiator hose, it was the plastic end near the radiator that failed first, at around 180k miles) than the thermostat. And it sounds like if anything, the thermostat failure mode is that it sticks open, which is not going to blow anything up.

But on the thermostat, does anyone have a good number on what the resistance of the heating element should be? My 2001 3.0i has a 50k-mile old, dealer-installed Genuine BMW thermostat, and I don't have an OBD code or engine light, but ...

Recently I've been getting the following code on my Foxwell:
1-DME, 7B DME: Activation, map cooling
Looking that up gives reports of it being the thermostat heating element. I measured the resistance of my heating element as 3.7 Ohms, which seems in the right ballpark, but am wondering if it is in spec.

OP, related to this, have you measured your thermostat heater resistance? Scanner info (note that I have no issues I can see other than that code which only appears in the Foxwell BMW diagnostics)? Have you tried leaving the connector unplugged to see if your engine runs hotter? Suggested for debugging, not as the solution.

I have the same fault code in mine! This is rom the STANT branded thermostat housing that was made in germany.

A new heater element should be around 15 to 16 ohms. So 3.7 ohms would def be considered "shorted."

[oldskewel]

Originally Posted by RocketyMan

I have the same fault code in mine! This is rom the STANT branded thermostat housing that was made in germany.

A new heater element should be around 15 to 16 ohms. So 3.7 ohms would def be considered "shorted."

The new one just arrived. I could not get a Wahler in time (the one I just took out is a Genuine BMW, made by Wahler), so got a Mahle. Resistance measures at 15.8 Ohms.

I now fully expect this will solve my DME error code but, as listed in the other thread, I seem to have other problems right now.

[X5only]

Don't forget to replace the dual temperature switch 13621703993 and its cheap. I replaced both the thermostat and dual coolant temp sensor. I kept getting DME error 2EF4/82 - Engine characteristic map thermostat, Mechanics. Dual temp sensor was dark on one side and sparkling clean on the other - looked strange and I don't think it was delivering the correct data.

[oldskewel]

Originally Posted by X5only

Don't forget to replace the dual temperature switch 13621703993 and its cheap. I replaced both the thermostat and dual coolant temp sensor. I kept getting DME error 2EF4/82 - Engine characteristic map thermostat, Mechanics. Dual temp sensor was dark on one side and sparkling clean on the other - looked strange and I don't think it was delivering the correct data.

https://www.realoem.com/bmw/enUS/sho...69#13621703993



I don't have any known errors for that part, and plan to currently focus on the known faults. Also, that part (am familiar with it, but thought it was the sensor [not switch, let alone double switch, as it is called] used by the instrument panel temp gauge) seems to be at the back end of the head, under the intake manifold, so it's not like I'm "in there" ... yet

Any info on accuracy of it being called a switch vs. double switch (and if so, the temperatures) vs. sensor. I see real OEM calls it a double switch, and somewhere referred to it having a four wire connector, but then it seems to also be common knowledge that it is the CH temp sensor. ???

[RocketyMan]

Originally Posted by oldskewel

The new one just arrived. I could not get a Wahler in time (the one I just took out is a Genuine BMW, made by Wahler), so got a Mahle. Resistance measures at 15.8 Ohms.

I now fully expect this will solve my DME error code but, as listed in the other thread, I seem to have other problems right now.

I think it's interesting how your thermostat heater failed the same way as mine. I still haven't replaced mine yet even tho I have a replacement part. ERgh!