BMW E46 Fanatics Forum banner

How many thermostats have failed in your car(s)

  • 0

    Votes: 36 47.4%
  • 1

    Votes: 33 43.4%
  • 2

    Votes: 5 6.6%
  • 3

    Votes: 0 0.0%
  • 4

    Votes: 0 0.0%
  • 5

    Votes: 1 1.3%
  • 6

    Votes: 0 0.0%
  • 7 or more

    Votes: 1 1.3%
1 - 20 of 28 Posts

·
Slow in, slower out
Joined
·
4,754 Posts
Discussion Starter #1 (Edited)
How many thermostats have failed in your car or cars?


M52TU and M54 thermostats are a well known weak spot in BMW cooling systems. They usually fail open causing the car to run cold, usually throwing a check engine light. An OBDII code reader will show a P0128 (Coolant below regulating temperature). I don't know what the factory or Peake code is for this failure.

I had another one die this week. It failed closed while driving to work resulting in an instant overheat and steam display. I don't know if I damaged anything. A few more days of driving will be required before I know if I'm losing coolant due to a blown head gasket. My previous thermostats failed open.
 

·
Registered
Joined
·
76 Posts
As far as I know I haven't had one fail. While I did get a P0128 code a week or so ago, my fan was running excessively at the time (which I found odd) and according to a tech I discussed it with, that was the cause of the code. It has not shown up since nor have I had any indications of abnormal running temperatures. How many total have you had fail?
 

·
Slow in, slower out
Joined
·
4,754 Posts
Discussion Starter #5
The one that failed this week was #5 for me. A friend called me a freak of nature.
 

·
Registered
Joined
·
2,454 Posts
It didnt actually fail, but I had mine replaced with the updated thermostat around 50K for peace of mind.

Old part: 11530139877

New part: 11537509227
 

·
Registered
Joined
·
555 Posts
It didnt actually fail, but I had mine replaced with the updated thermostat.....
I did the same. I changed mine at around 80k as preventative maintenance.
 

·
Registered
Joined
·
5,486 Posts
None in 2 BMWs I owned (one M52Tu and one M54)and none yet in the one I own now(M54).

I have a brand new OEM thermostat siting in my basement,bought it when I put my Stewart WP in, as I heard many people experienced thermostat failure right after replacing wp to Stewart. 10kms(6k miles) later, still waiting for the original to give up but it wont.

Since we're there, I also have a new OEM expansion tank sitting right next to the thermostat in the basement, as I refuse to change it without seeing how long my original one can take. So far 180kms(112k miles), original thermo and ET.
 

·
Registered
Joined
·
1,752 Posts
On my previous E46 I had a leaky thermostat replaced under warranty at around 20k miles. Never had another issue in the next 40k with that car or the 10k miles or so that I have had my ZHP.


Sent from my iPhone using BimmerApp
 

·
Slow in, slower out
Joined
·
4,754 Posts
Discussion Starter #15
I appear to be the exception rather than the norm. I thought there would be more people with 3+ failed thermostats.

Oh well. I got 10 years out of the original battery, radiator, and coolant reservoir so I guess I'll consider the thermostats to be a small offering on the altar of crappy parts from Bosch/VDO/Behr/Siemens/Lucas/Tyco/ZF/Lemforder.
 

·
Registered
Joined
·
1,405 Posts
I replaced the first one at about 30K. I overhauled the entire cooling system a couple of years ago when the car was at about 55K. That one failed last week. It failed open, and I replaced it with a Wahler unit. I think that this was the same brand that I had used previously (both times). Never have had a thermostat issue before in almost 50 years of driving.
 

·
Registered
Joined
·
4,269 Posts
I replaced my original at 123,000 miles, not because it failed, but because I replaced it with a new one as preventative maintenance.
 
Joined
·
33,632 Posts
Mine stuck open at 125k

Lasted pretty long I guess :dunno:
 
1 - 20 of 28 Posts
Top