M5Racer

Hi all, my service engine light came on, went to the dealer this morning it came to be a Bad Thermostat, is this common? My vehicle is out of warranty but I've purchased extended warranty so I should be good to go.




Here is the part number 11531407772

http://www.realoem.com/bmw/showparts...66&hg=11&fg=35

AndrewBailey

Bad thermostat seems common in E39s. My first (non M5) one had a thermostat failure in the first month. My second (the M5) had a thermostat failure in the first month.

Both stuck slightly open. Symptoms included a huge delay in warming up and a low temperature on the motorway. A low engine temperature resulted hence the SES light I would think.

E55AMG2

Thermostats fail, it's not a rare occurence on BMWs (especially for E36's)

M5Racer

Thanks.

Dash

As mentioned in another thread, I've recently had this problem as well. Stuck slightly open, slow to warm up, slightly cool while driving. Resulted in some misfire codes.

R748

You will also need the profile gasket: 11531312287.
You will also need 6 o-rings for the connecting pipes:

4 of the #9 in the picture below:

http://www.realoem.com/bmw/showparts...67&hg=11&fg=35

2 of the #11 in picture below:

http://www.realoem.com/bmw/showparts...65&hg=11&fg=30

I did this myself recently, and unless you are very comfortable and used to working with the M5, I would advice that you let a good mechanic handle it. The thermostat is a real pain to change on this car. Especially the draining of the old coolant. It is quite messy since the VANOS oil lines go over the thermostat housing and it needs to be removed to get the housing out. This means a bit of oil spillage that needs to be mopped up.

claymax

Yep, same thing happened to me, SES codes and one limpy experience. Next trip to dealer they replaced;

Double Temperature Switch (Coolant temp switch) and Thermostat. Here was the cost breakdown;

11-53-7-835-558 Thermostat 121.00
11-53-1-312-287 Seal Ring 43.50
11-53-1-406-249 O-Ring (4 @ $2.01) 8.04
32-41-2-228-873 Suction Hose 39.25
82-14-1-467-704 Antifreeze 19.25
13-62-1-703-993 Eng. Colant Temp Se 18.30
Total Parts 249.34
Labor 438.42
Total $687.76

I have a stout warranty that I pay $75 per visit for, otherwise I would be livid.


Other work as an FYI

Replacing both Upper Crankcase Vent Hoses

11-15-1-406-952 Vent Hose $16.24
11-15-1-406-953 Vent Hose 14.84
Total Parts 31.08
Labor 92.75
Total $123.83



Replacing Return Power Steering Line

32-41-2-228-868 Return Pipe $38.00
07-12-9-952-109 Clamp/Recall 6.76 (2 @ $3.38)
07-12-9-952-107 Clamp/Spec 2.60
17-21-1-742-636 O-Ring .57
ATF Bulk ATF Qts 4.00
Total Parts $51.93
Labor 205.22
Total $257.15

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TeXJ

do check your crank case vent hoses. I replaced mine when I did the t-stat change. You can get a good tstat from parts importer. I got a Werner or something like that. That is a good tstat. I forgot the exact price, but it was under $50, I want to say something like $15. But I can't remember. Also, check those o-rings. Mine looked really good. I replaced 3 of them and so far 3+ months no leaks.

silver02m5

Some more advice for the DIY mechanic:
1. The job takes a good 4 to 6 hours if you choose NOT to replace the water pump, so plan on spending the better part of a day in your garage.
2. Get the TIS CD ROM from eBay for some pretty good instructions before starting and replace all of the gaskets and o-rings that they recommend.
3. DO NOT open the VANOS oil lines. You can get the thermostat housing out without opening them up. Just remove the two bolts that secure them to the housing, and remove the temperature sensor.
4. The job is much easier if you remove the fan. It comes out in less than 5 minutes if you have a tool that holds the pulley while you loosen the fan nut (it loosens clockwise).
5. BEWARE OF THE FAN SHROUD. It appears to be make of plastic, but it must be made of a razor-like alloy. It is wickedly sharp.
6. If your thermostat has never been changed, and the car is a few years old, the 3 tubes and 6 o-rings that connect the thermostat housing to the top of the engine may be very difficult to pull loose (mine were). Get a long round bar and VERY carefully pry between the housing and one of the flanges at the connection to the top of the engine. The tube should pop out on that side. Then just do the same on the other side.
7. Some people will try to tell you that you must remove the water pump to replace the thermostat, but this is not true. But you may still want to replace the water pump at this time if it has never been replaced.
8. By the time that you replace all of the gaskets, o-rings, coolant, etc. you will have spent about $100 to $150, but the stealer will hit you for $750 to $900, so it is worth the trouble if you are brave enough.

Good luck!!

misterpython

Hey, I just got the tstat code and i'm running cool. At the moment I really dont have the 800-1100 bucks its going to take to get it fixed. I was wondering if you guys knew what the harm was of just letting the thing run cool. I always thought that an engine would run better cool. Not sure if this applies to the coolant/oil temp or just the outside air temp.

I'm not going to be able to fix it for at least a month and I was wondering if I should find the money somewhere else, and what kind of damage it may do to my beloved beast.