tjts1, can you update the first post? I’ve been scouring this thread and the board to finish this project, and I think one post in the beginning would be a lot easier to read! This is my own summary of what other members have said and my own experience. And by the way, a thousand thanks to all of you! I couldn’t have done this without all of your help.
Parts you will need:
• Plastic Coolant Pipe from Block (Part # 11531714738) (
Diagram Link)
*NOTE: Make sure this is OEM! Aftermarket pipes have been found to leak, as noted
here*
• O-Ring for Pipe (Part # 11531709157)
• Throttle Body Gasket (Part # 13541743261) (
Diagram)
• Upper – Lower Intake Gasket (Part # 11611717761) (
Diagram)
• Lower Intake – Block Gasket (Part # 11611734684) (
Diagram)
• BMW Antifreeze (Part # 82141467704)
Or whatever brand you choose, of course.
• 5/8” Coolant Hose
• 5/16” Fuel Hose (Make sure it is fuel INJECTION hose, not fuel hose for a carb)
• 19/32” Vacuum Hose
I found all three hoses at Advance.
*NOTE: DO NOT use fuel hose for vacuum hose or vice versa. If improper lines are used they could expand or collapse.*
Under the manifold, as pictured in this thread, there is a mess of hoses.
In addition, you get rid of the throttle body heating plate, which as many have said, is of no use. Most of the hoses are unnecessary, and we’re getting rid of them as well as rerouting the vacuum lines to make future maintenance easier, and limit the number of possible leak points. Most importantly, you’re getting rid of the two junctions. You’re replacing the plastic coolant pipe because it’s relatively cheap, and they tend to crack over time on M42s. In the end you’ll have three hoses:
• One vacuum hose from the valve cover to the throttle body
• One vacuum hose from the idle control valve to the intake elbow
(the other side of the idle control valve will go to the same place, but you can extend the hose if you’d like to make the ICV easier to access.)
• One coolant hose from the coolant pipe’s outlet to the nipple on the head. This is a personal preference; some have simply plugged the two holes. Read more
here.
These two hoses are NOT the same size. Even though I trust the results found here, I'm still wary of my head cracking, so I thought I would connect the two just to be safe. A local plumbing supply store rigged this up for me, and I haven't had any leaks. It's not pretty, but it works.
I'll report back in a few months, but it seems fine. Just in case I do find a leak, I ran this just outside of the lower intake, so I can plug the lines with some bolts if necessary.
When you’re done, don’t forget to bleed the cooling system! Here’s
how.
Other things to think about while you’re down there…
• Are the two rubber coolant hoses that meet the plastic pipe we’re replacing in good shape? (#s 4 and 22
here)
• Do you want to install a catch can? It’s really not necessary if you use synthetic oil, but some have put one in line between the valve cover and the throttle body.
• Is it time to upgrade your injectors? Many have upgraded to Ford’s 4 pistil injectors (as opposed to our 1 jet) for better atomization of fuel. Read more
here.
• If you don’t want to change out your injectors, at least give them a clean! Pelican Parts explains
how.
• The rubber hoses going into the hard lines on the lower intake. You have to buy some short pieces that lead from the hard lines to the fuel rail, so you might as well do a little preventative maintenance and buy a few feet. (#s 15 and 16
here)
• Clean out your AFM sensor!
