Diy BMW E65 E66 How To Replace Your Thermostat

The time finally came when I said, I’m really tired of seeing this engine light on my BMW’s dashboard.  I was pulling code P0128 on my OBD 2 reader, I knew it was a bad thermostat so I took the proper measures and said lets do this.  Ordered my BMW E65 E66 thermostat part and to the garage we went.  I really won’t be able to describe the project as well as if you just watch the diy Bmw E65 E66 replacing your thermostat project that I have on YouTube.  You can see that video below.  This project was done on my E65 750i, I believe the earlier model E65’s E66’s, 4.4 Liter engines it’s easier to get to the thermostat.

Important Tools For This Job.
10mm socket with a choice of different socket wrenches.
Razor blade or paint scrapper for old gasket removal.
New 1 Gallon of BMW Coolant & 1 Gallon of Distilled Water.
T30 or also called Torx Bit 30.  (You can see this is video below)
Flat Head Screw Driver

New Lower Hose & Lower Hose Sensor

Problems I faced with this project were as follows, I had trouble removing the lower hose from the thermostat, again my car is a 2006, this car has never had the lower coolant hose removed before and again this hose is slotted so don’t twist it just wiggle it again and again until you get it loose.  That was pretty much the only struggle other then that back 3rd 10mm bolt that holds on the thermostat, again pick your favorite weapon (tool) of choice and you’ll get it.

Again other projects you should consider if you have the money at this time would be to replace your BMW E65 E66 water pump and belts, during this project examine your water pump for gasket leaks and wiggle your water pump pulley to see if you have a bad water pump bearing, also examine your belts for worn belts.  Also examine your lower coolant hose as well.  If you decide to replace your BMW water pump later as I will do, then you will have to replace the BMW coolant again.

Watch the video below videos speak a 1000 words, and Thank you for watching, and Happy Fixing.




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2 Responses to Diy BMW E65 E66 How To Replace Your Thermostat

  1. Eddie says:

    Hello, I loved watching your videos, they give a lot of helpful information. I own a 745Li 2002. I have a problem with my transmission. When I come to a stop sign it feels like someone hit me from the back. Have you ever experienced this? I also have a problem with my ventilation system. The driver side gives off heat while the passenger side gives off AC but the controls are both set to AC. Have you ever heard of this before? Would you be able to give me any help on these subjects? Thanks. Eddie

    • Chris says:

      Hello Eddie,
      Yes I actually have your same problem as your describing from getting hit from behind, I made a video letting folks know what the issue is. If you go to this websites videos tab, look for the video titled BMW E65 E66 Transmission Problems Might Really Be The Guibo Joint Symptoms. That video will show you exactly what your problem is, a view saw that video and let me knew he fixed his Guibo and his car’s running great now. For your 2nd question about the A/C on one side and Heat on the other. Hmm I haven’t heard this one before, some settings in your Idrive must be off. That’s my 1st guess it’s computer setting related, try getting deep into the settings for A/C Heat Control and let me know what you come up with. I also have a couple videos talking about changing heated seats etc try to follow that video for setting controls. Thanks for stopping by, hope this helps.

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