[Xerix]

Hey Everyone,

So I will be doing a coolant flush in the spring (Never done before) and am thinking I should replace the water pump and maybe the belt tensioner. Does anyone know the manufacturer of our mechanical water pumps? I see GMB Water pumps for 60% less than the BMW pump but am not sure who the OE manufacturer is.

If you know the expected life to get out of these parts it would be nice to know as well.

I also had to top up the coolant last week but didn't notice any leaks. Any idea where the coolant might be leaking or possible failure points to be inspecting?

Thanks

[UT335d]

From what I've seen from other people's experience it seems like the lifespan of the original water pump ranges from 120k-160k miles. Mine failed right in the middle of that range at 140k. When the bearing inside starts failing it will begin leaking coolant little by little and it can be very gradual and seem like a phantom coolant leak. If you are over 100k and still have your original water pump I would definitely get ahead of it completely failing.

[335dlci]

Pressure test it. There are no such things are phantom leaks with proper tests.

[Xerix]

I don't have anything to pressure test it with just yet. I will take the EGR Cooler off first and try to look inside to see if it is wet. I looked under the oil cap and it looks perfectly normal and the engine feels and sounds normal.

Also, how would we do a pressure test? From the coolant reservoir or thru the glow plugs? or both?

When I took the cooler cap off I heard a little air come out of it, Ill try next time after leaving it over night to see if it still makes the sound.

Also, based on all my readings, a lot of people seem to have issues with EGR Coolers cracking with no signs of issues other than the coolant disappear on them. So I am really hoping that is all it is.

Forgot to ask, anyone know the OE for our coolant pumps?

Thanks

[335dlci]

Originally Posted by Xerix

I don't have anything to pressure test it with just yet. I will take the EGR Cooler off first and try to look inside to see if it is wet. I looked under the oil cap and it looks perfectly normal and the engine feels and sounds normal.

Also, how would we do a pressure test? From the coolant reservoir or thru the glow plugs? or both?

When I took the cooler cap off I heard a little air come out of it, Ill try next time after leaving it over night to see if it still makes the sound.

Also, based on all my readings, a lot of people seem to have issues with EGR Coolers cracking with no signs of issues other than the coolant disappear on them. So I am really hoping that is all it is.

Forgot to ask, anyone know the OE for our coolant pumps?

Thanks

That noise is normal. Its done through the expansion tank. Im.not sure what you mean by testing through the glow plugs? Removing your cooler to find a leak is just silly when coolant will drip anyways.

[Xerix]

Originally Posted by 335dlci

That noise is normal. Its done through the expansion tank. Im.not sure what you mean by testing through the glow plugs? Removing your cooler to find a leak is just silly when coolant will drip anyways.

I was planning on leaving the coolant lines connected to the EGR and try to move it enough to stick a camera into it. Hopefully coolant lines don't need disconnecting. Worst case, I can try to pressure test the EGR in a bucket of water if I have to completely remove it.

Re: Glow Plugs: I saw online that you can do a pressure test for head gasket leaks thru the glow plugs (leak down test), but that's after I check the EGR cooler as it would require a bit of work.

As for the pressure test thru the expansion tank, how much pressure (PSI) do you think I should put into it to perform the test?

Thanks

[Xerix]

I found online thru Pelican Parts the pressure test is supposed to be @ 21.8PSI with no greater drop than 10% of PSI in 2 minutes. Ill give that a try this weekend hopefully.

https://www.pelicanparts.com/BMW/tec..._Leak_Test.htm

[Persian Whisperjet]

I am at 138K miles and have been losing a few ounces of coolant every time I check (three times a year). I am going to yank the pump and see if that fixes it.

[kbsilver]

Just another data point. I'm at 110K miles and have never added a drop of coolent. Probably should change it but it will get done with the water pump when it's time. As the diesel does not run as hot as gasoline engine, I'm figuring it's not very hard on the cooling system in general.

[Xerix]

Question on the aside... After checking the diagram on the radiator on RealOEM I noticed 2 drain plugs but one seems grayed out. How many drain plugs does our car have on the radiator?

[Persian Whisperjet]

Just did the water pump -- thanks to Brad Tourt for some pointers (see below). The main pain in the neck is removing the engine fan, which is covered in newTIS but they omit mentioning that there is a trans cooler bolted to the fan that has to be released from below (pic 1). Moving around the coolant lines is made easier if you release the 10mm bold holding the coolant pipe right behind the oil filter housing (pic 2). If the water pump is original, removing the gasket requires a few whacks with a chisel and some yanking yielding a gasket that looks like it was interviewed by the East German police (pic 3). The car lost exactly one gallon of coolant in the procedure and is now running at exactly 87 C.