Plastic Coolant Pipe Replacement

[OntarioZed]

Doing a cooling system overhaul while my 2003 Z4 3.0 is in storage and wanted to also replace the two plastic coolant pipes that hide under the intake manifold as well. I have been able to remove and/or loosen a couple of the bolts that hold these pipes in, since I also have the oil filter housing off for a gasket change, which gives a little better access, but not able to get them all.

Has anyone ever replaced these hard plastic lines without removing the intake manifold? If so, could you describe how.

Thanks in advance.

[dbarton62]

Changed mine out 2 winters ago
There are a couple of bolts behind/ under the IM that I would not like to tackle removing without it being out.

[jclausen]

I did them on my 525 you have to remove the manifold once the manifold is off you can replace the rubber caps and hoses at the back of the manifold and the cyclone valve and hoses and intake air boot

[OntarioZed]

After removing the oil filter housing, DISA, idle control solenoid, throttle body, CCV system and sound generator I had enough access to remove both hard plastic coolant lines without removing the intake manifold. Oil filter housing gasket was leaking anyway and the CCV system was old and brittle so may as well replace while I'm in there.


I will also be replacing the rad (expansion tank was replaced in the fall), water pump, tensioners, idler pulleys, both serpentine belts, thermostat/housing, top and bottom rad hoses, all o-rings in remaining coolant hoses, intake air boot, VANOS oil line, switching to an aluminium water pump pulley, and spark plugs. I was also able to source an aluminum alternative for one of the hard coolant lines, but bought a new BMW plastic one for the other. I want to rebuild the DISA as well with the G.A.S. kit. My DISA was replaced in 2009 and seems to be tight, but you never know. Should be a good refresh for the coming summer months.

Thanks for your replies!


Then on to the brakes and suspension!