BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Mechanical Maintenance: Break-in / Oil & Fluids / Servicing
 
Steve Thomas BMW
Post Reply
 
Thread Tools Search this Thread
      03-13-2017, 01:59 PM   #1
JH M3
Second Lieutenant
JH M3's Avatar
United_States
23
Rep
201
Posts

Drives: 2009 E90 M3 6MT
Join Date: Jun 2008
Location: Newport, RI

iTrader: (0)

How Long Can I Drive With Bad Thermostat?

Just got the CEL, increased emissions warning, and thermostat fault code. I think the thermostat is stuck open since it's running on the cool side. The dealer here wants almost $2000 to replace the thermostat and water pump (I figured the pump should get replaced as well since I'm at 55,600 miles). I found an independent shop that will do it for $1100 but they can't fit me in until next Monday. Since it's not running hot I think I'm OK driving it for a bit but my question is how much? I've got probably 2-3 trips at about 40 miles each to make this week.

The alternative is I replace the thermostat myself and forego the pump. I don't feel entirely comfortable with my abilities to replace the pump but the thermostat seems relatively straightforward.
__________________
Appreciate 0
      03-13-2017, 02:24 PM   #2
Powashiftin
Captain
80
Rep
721
Posts

Drives: E92 M3
Join Date: Apr 2010
Location: NJ

iTrader: (1)

Quote:
Originally Posted by JH M3 View Post
Just got the CEL, increased emissions warning, and thermostat fault code. I think the thermostat is stuck open since it's running on the cool side. The dealer here wants almost $2000 to replace the thermostat and water pump (I figured the pump should get replaced as well since I'm at 55,600 miles). I found an independent shop that will do it for $1100 but they can't fit me in until next Monday. Since it's not running hot I think I'm OK driving it for a bit but my question is how much? I've got probably 2-3 trips at about 40 miles each to make this week.

The alternative is I replace the thermostat myself and forego the pump. I don't feel entirely comfortable with my abilities to replace the pump but the thermostat seems relatively straightforward.
Check the DIY section. Parts can be had for a few hundred bucks. Good luck
Appreciate 0
      03-13-2017, 03:13 PM   #3
Locksmythe
First Lieutenant
Locksmythe's Avatar
United_States
38
Rep
371
Posts

Drives: 2009 e92 M3 AW/FR
Join Date: May 2009
Location: Virginia

iTrader: (0)

The answer is indefinitely. But your gas mileage will go down by 30+ % because the O2 sensor calculations will not be able to process correctly and the system will default to max fuel mix to compensate. The fuel costs will exceed repair cost in a few months.
Appreciate 0
      03-13-2017, 09:19 PM   #4
JH M3
Second Lieutenant
JH M3's Avatar
United_States
23
Rep
201
Posts

Drives: 2009 E90 M3 6MT
Join Date: Jun 2008
Location: Newport, RI

iTrader: (0)

Thanks. So far I haven't seen a real noticeable drop in fuel economy and the heater still works fine. After doing a little more research I decided to attempt the thermostat and pump change myself. I found a good price on a new pump so all told it's going to cost me about $500 including purchasing a few tools that I need. I'll post an update in the DIY forum when complete.
__________________
Appreciate 0
      03-14-2017, 10:35 AM   #5
Richbot
Brigadier General
815
Rep
3,761
Posts

Drives: Jerez Black E90
Join Date: Sep 2007
Location: STL

iTrader: (3)

Which Tstat code is it? I wouldn't (and didn't, when I was in a similar situation at 90,000 miles) change the pump without reason to believe it's having problems, but it's up to you. Not a hard job at all, just messy, I'd recommend pulling the belly pan off so the coolant you spill hits a drip pan rather than getting trapped in the belly pan where you'll smell it for months and it'll make you paranoid you've messed something up and have a leak

Last edited by Richbot; 03-14-2017 at 10:40 AM.
Appreciate 0
      03-14-2017, 10:59 AM   #6
JH M3
Second Lieutenant
JH M3's Avatar
United_States
23
Rep
201
Posts

Drives: 2009 E90 M3 6MT
Join Date: Jun 2008
Location: Newport, RI

iTrader: (0)

002B59 is the code. I bought a catch pan in anticipation that it will be a messy job. I found a new genuine pump for about $100 less than the average price I've seen so I figured it would be a good idea to replace it as well. Talking to my dealer some cars go 50k before the pump fails and some go 100k. In other words it's a total crapshoot. Sounds like your car is in the latter category.
__________________
Appreciate 0
      03-14-2017, 11:15 AM   #7
TWiTCHY
Colonel
TWiTCHY's Avatar
United_States
221
Rep
2,467
Posts

Drives: '13 AW E92 M3
Join Date: Jul 2008
Location: WA

iTrader: (6)

I drove on a bad thermostat and temperature sensor for 10 months before replacing it. Did not experience the lower gas mileage as another user stated, but it did take much longer for the car to warm up to operating temp.
Appreciate 0
      03-14-2017, 11:16 AM   #8
tdott
Major
450
Rep
1,468
Posts

Drives: M3
Join Date: Nov 2010
Location: FL / T.Dot

iTrader: (2)

Water Pumps on Ms usually last a long time, he might be talking about all BMWs not just the S65. I haven't heard of many failures yet, but it still might be a good idea, why not.

A friend had his S54 wp last until 280k miles.

I did my tstat and flush at 80k and was debating changing my pump, but my friends convinced me other wise. It's really not hard to get it, and it's not really a 'while you are in there' kinda thing all you are saving is some coolant and a few minutes.
__________________
Appreciate 0
      03-14-2017, 12:27 PM   #9
Richbot
Brigadier General
815
Rep
3,761
Posts

Drives: Jerez Black E90
Join Date: Sep 2007
Location: STL

iTrader: (3)

Quote:
Originally Posted by JH M3 View Post
002B59 is the code. I bought a catch pan in anticipation that it will be a messy job. I found a new genuine pump for about $100 less than the average price I've seen so I figured it would be a good idea to replace it as well. Talking to my dealer some cars go 50k before the pump fails and some go 100k. In other words it's a total crapshoot. Sounds like your car is in the latter category.
Maybe I missed one but I have yet to see anybody report a failed S65 water pump on this forum, that sounds like the M50/M52 engine lore being applied to a totally diffferent engine

2B59 could just be the $75 thermostat sensor. You might not even need to crack the system open to resolve the code.
__________________
Appreciate 0
      03-14-2017, 12:28 PM   #10
Richbot
Brigadier General
815
Rep
3,761
Posts

Drives: Jerez Black E90
Join Date: Sep 2007
Location: STL

iTrader: (3)

Quote:
Originally Posted by TWiTCHY View Post
I drove on a bad thermostat and temperature sensor for 10 months before replacing it. Did not experience the lower gas mileage as another user stated, but it did take much longer for the car to warm up to operating temp.
This was my experience getting 2B59 code only as well, drove it like that for about 5 months, intermittent 2B59 code when it was cold out, usually during the first few miles of driving after a cold start. I have no proof the thermostat was bad, changed it while I was in there because I noticed slow warmup as well and needed to do a coolant flush anyway, but it may have all just been poor sensor performance, the factory sensor had a lot of oxidation and some deposits on it when I took it out, though I think the sensor had an intermittent connection problem as it would sometimes throw out implausible values, hence the code
__________________
Appreciate 0
      03-14-2017, 12:47 PM   #11
JH M3
Second Lieutenant
JH M3's Avatar
United_States
23
Rep
201
Posts

Drives: 2009 E90 M3 6MT
Join Date: Jun 2008
Location: Newport, RI

iTrader: (0)

Thanks. Based on all the feedback I've decided to not replace the pump but I'm going to replace the sensor and the thermostat. Looks like an aftermarket sensor is less than $15 so why not.
__________________
Appreciate 0
      03-15-2017, 10:16 AM   #12
Locksmythe
First Lieutenant
Locksmythe's Avatar
United_States
38
Rep
371
Posts

Drives: 2009 e92 M3 AW/FR
Join Date: May 2009
Location: Virginia

iTrader: (0)

Quote:
Originally Posted by TWiTCHY View Post
I drove on a bad thermostat and temperature sensor for 10 months before replacing it. Did not experience the lower gas mileage as another user stated, but it did take much longer for the car to warm up to operating temp.
My temp sensor was also very corroded so I probably needed to replace both (and did). Makes sense that the sensor would have been the critical factor in my O2 calculation woes rather than the thermostat.
Appreciate 0
      03-15-2017, 10:20 AM   #13
Locksmythe
First Lieutenant
Locksmythe's Avatar
United_States
38
Rep
371
Posts

Drives: 2009 e92 M3 AW/FR
Join Date: May 2009
Location: Virginia

iTrader: (0)

Oh, one piece of advice: I followed a DIY that said to remove the wire clips with a plier. That only applies to the clips on hoses, and a screwdriver works better for that anyway. The clips on the electrical connections like the sensor are just squeezed by pushing on the center of the wire toward the connector, which releases the tabs on each side. You have to remove the sensor connector to get to the thermostat anyway, so replacing the sensor only adds a minute or two to your thermostat job.
Appreciate 0
      03-15-2017, 11:05 AM   #14
JH M3
Second Lieutenant
JH M3's Avatar
United_States
23
Rep
201
Posts

Drives: 2009 E90 M3 6MT
Join Date: Jun 2008
Location: Newport, RI

iTrader: (0)

Thanks for the advice. Strangely enough after I filled up this morning the Check Engine warning went away. I'm going to clear the codes and see what happens. I'll probably end up replacing the thermostat and sensor anyway since they're more than likely on their last leg even if they are working again now.
__________________
Appreciate 0
      03-15-2017, 11:19 AM   #15
Richbot
Brigadier General
815
Rep
3,761
Posts

Drives: Jerez Black E90
Join Date: Sep 2007
Location: STL

iTrader: (3)

My 2B59's sometimes cleared on their own from the dash, but were stored
__________________
Appreciate 0
      03-15-2017, 01:55 PM   #16
dparm
Major General
dparm's Avatar
United_States
1301
Rep
5,601
Posts

Drives: Corvette Grand Sport
Join Date: Jun 2013
Location: Chicago, IL

iTrader: (0)

Quote:
Originally Posted by Locksmythe View Post
The answer is indefinitely. But your gas mileage will go down by 30+ % because the O2 sensor calculations will not be able to process correctly and the system will default to max fuel mix to compensate. The fuel costs will exceed repair cost in a few months.

Yeah, but running rich for long periods of time is not healthy for the engine or emissions components. I would get it fixed as soon as you can.
__________________
Now: 2017 Corvette Grand Sport
Past: 2011.5 M3 sedan ZCP
Appreciate 0
      03-20-2017, 09:29 PM   #17
JH M3
Second Lieutenant
JH M3's Avatar
United_States
23
Rep
201
Posts

Drives: 2009 E90 M3 6MT
Join Date: Jun 2008
Location: Newport, RI

iTrader: (0)

So 5 days after clearing the code it hasn't come back. Not sure if it's worth the hassle of changing the thermostat right now although of course the parts I ordered arrived right after the fault cleared.
__________________
Appreciate 0
      03-21-2017, 10:06 AM   #18
Locksmythe
First Lieutenant
Locksmythe's Avatar
United_States
38
Rep
371
Posts

Drives: 2009 e92 M3 AW/FR
Join Date: May 2009
Location: Virginia

iTrader: (0)

As Richbot said, the code will come and go; it did for me as well. The problem is insidious - it will resurface.
Appreciate 0
      03-21-2017, 02:00 PM   #19
monterey
Captain
monterey's Avatar
158
Rep
976
Posts

Drives: 2008 M3
Join Date: Mar 2016
Location: San Francisco

iTrader: (1)

Quote:
Originally Posted by Locksmythe View Post
The answer is indefinitely. But your gas mileage will go down by 30+ % because the O2 sensor calculations will not be able to process correctly and the system will default to max fuel mix to compensate. The fuel costs will exceed repair cost in a few months.

How much truth is there in this? I had the code come up a few months ago and I disregarded it. After it was cleared, it hasn't come back but my gas mileage has always been terrible.
__________________
A job is nothing but work.
Appreciate 0
      03-21-2017, 04:00 PM   #20
Locksmythe
First Lieutenant
Locksmythe's Avatar
United_States
38
Rep
371
Posts

Drives: 2009 e92 M3 AW/FR
Join Date: May 2009
Location: Virginia

iTrader: (0)

I drove with the temp sensor/thermostat code randomly coming and going for a long, long time because I didn't see anything that said it was important, and it would not come back when cleared. My gas mileage went down to around 13mpg. I assumed it was because I was doing only city driving on my commutes. After replacing both, and the sparkplugs, the fuel economy went up by almost 50%.
Appreciate 0
      03-22-2017, 09:17 AM   #21
dparm
Major General
dparm's Avatar
United_States
1301
Rep
5,601
Posts

Drives: Corvette Grand Sport
Join Date: Jun 2013
Location: Chicago, IL

iTrader: (0)

Quote:
Originally Posted by monterey View Post
How much truth is there in this? I had the code come up a few months ago and I disregarded it. After it was cleared, it hasn't come back but my gas mileage has always been terrible.

There is plenty of truth to it. Fuel maps are very complex so as soon as certain variables are way out of whack, the car goes into a "cautious" mode which results in excess fuel consumption.
__________________
Now: 2017 Corvette Grand Sport
Past: 2011.5 M3 sedan ZCP
Appreciate 0
      03-22-2017, 09:28 AM   #22
oolas3
Captain
330
Rep
796
Posts

Drives: BMW
Join Date: May 2015
Location: United States

iTrader: (0)

Running overly rich can wash the oil off the cylinder walls and break down oil faster.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 10:23 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST