X5 E53 2005 Heater Control Valve

[Fifty150hs]

Originally Posted by talljames

So, my expansion tank and cap arrived. But a thought crossed my mind. I know my heating isn’t working in the cabin - not sure if fsr, aux water pump or heater control valve yet. But, if I put this new expansion tank in do I run the risk of cracking it because of my heating problem?

Probably not, but if your aux water pump isn't working you're going to have a time trying to bleed the system. Also, if your aux pump isn't working, that could be the source of your problems with cabin heat. Simplest way to tell is to turn the key to on, but don't start the car. Turn the heat all the way up then pull the expansion tank cap. If the aux pump is working you'll have a little stream of coolant running into the tank up near the cap.

[andrewwynn]

Pressure and heat are directly related. Use menu 7 to monitor temp and if it's below about 110C it's not going to put undue stress from pressure.

[andrewwynn]

Wife's aux pump is not working properly but she gets heat ok when driving just not when stationary. We do have to set the temp a couple degrees hotter on her car to get the same comfort as mine. That's a good test though and worth determining

[talljames]

Fifty150hs ! Thanks. Great idea. Will let the forum know how it goes.

[andrewwynn]

On the foxwell this is where the aux coolant pump hides

[Fifty150hs]

Originally Posted by andrewwynn

On the foxwell this is where the aux coolant pump hides

Or you can just run a scan on the entire car and if there is a problem the code will show up. Plus, it will tell you if you have other issues.

[andrewwynn]

not necessarily ; my wife's aux coolant pump is not working, no codes related, but added bonus her car is pre-01 build so has the under-hood 20-pin obd port and also the programming is different on the pump so i can't find it in the foxwell to test it, i just know it doesn't pump because it doesn't send heat to the cabin like mine does and no sound/vibration.

[talljames]

Hmmm...interesting. Removed cap, turned key on, temp high, wheel to 3 dots red and checked. Sorry, fan was on. Coolent was low but no warning on dash. Could not see the drip from inside the expansion tank just below the cap but could hear a whining sound (perhaps the aux pump?). Filled the coolent up to correct height for the measuring float. Still no drip (but perhaps I didn’t wait long enough). Started engine and looked down into the tank and I saw drips from just below the cap inside.

Thanks for the images. Trying to find out if my iCarsoft one will do the job. I have also heard of another port under the bonnet of my car so maybe I need to connect there with an adapter.

[Fifty150hs]

Originally Posted by talljames

Hmmm...interesting. Removed cap, turned key on, temp high, wheel to 3 dots red and checked. Sorry, fan was on. Coolent was low but no warning on dash. Could not see the drip from inside the expansion tank just below the cap but could hear a whining sound (perhaps the aux pump?). Filled the coolent up to correct height for the measuring float. Still no drip (but perhaps I didn’t wait long enough). Started engine and looked down into the tank and I saw drips from just below the cap inside.

Thanks for the images. Trying to find out if my iCarsoft one will do the job. I have also heard of another port under the bonnet of my car so maybe I need to connect there with an adapter.

My aux pump also whined when it went out. Only reason I knew was that it showed up as a code when I ran a scan. Then I opened the cap and saw no stream of coolant like there should be. Replaced the pump and it's all good now.

[andrewwynn]

you need the 'high cluster' to get a low coolant warning on the dash; only cars made before 2000 July will have the 20 pin connector under the hood. The float will rise higher when the engine is running, you need to fill when engine is cold and not running. On the 3.0, it takes a few seconds each time you put in a few hundred ml, for it to settle down as the coolant works its way down into the engine. I topped off my wife's tonight, it took 3 or 4 passes to add maybe 500ml. I think i've finally found her leak though! update on that coming.

get your engine up to temp (90C ish), and while driving, check for heater output when coolant is full; if you don't have heat then, you probably have a stuck closed heater valve.

Usually no cabin heat means a stuck open thermostat and you won't achieve 90C maybe 60C or something and you won't be amazed by the heat coming out in the cabin.

When the engine is running, you should see a pretty solid stream 'peeing' sideways across the fill port on the coolant tank, not just dribble, but the aux pump i don't know exactly the program it uses to run; mine wasn't running for example when the engine was about 50C when i was doing testing tonight, i hit the 'activate' function and i could distinctly hear it kick on. (but it may have been on just lower speed)