Parts Catalog Accessories Catalog Tech Info Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Coolant Pipes Replacement
 
Bookmark and Share

Pelican Technical Article:

Coolant Pipes Replacement

Nick Czerula

Time:

5 hours5 hrs

Tab:

$200

Talent:

*****

Tools:

Set of sockets, wrenches, screwdrivers

Applicable Models:

BMW Z3 (1996-02)

Parts Required:

Coolant pipes, sealing O-rings, heater hoses, engine coolant

Hot Tip:

Work with a cool engine.

Performance Gain:

Car will cool down again, coolant leak repaired

Complementary Modification:

Change thermostat, flush cooling system.

BMW Z3 cooling system components include:

  • Radiator and coolant overflow tank.
  • Belt driven coolant pump bolted to the front of the engine block.
  • Belt driven fan attached to front of coolant pump. Viscous clutch controls fan speed based on engine temperature and rpms.
  • Electric (auxiliary) cooling fan attached to front of radiator. The cooling fan is controlled by the engine control module (ECM) via an output final stage.
  • Electrically heated thermostat.
  • Automatic transmission cooler or heat exchanger (if equipped).
  • Heater valve and heater core (for climate control).
  • Coolant level sensor inside expansion tank.
  • Coolant temperature sensor at cylinder head.
  • Radiator outlet temperature sensor
  • Coolant hoses and lines.

Z3 models with 4-cylinder engines have plastic coolant pipes that connect to the block and cylinder head to the heater core. The pipes are bolted in place and sealed with an O-ring. Over time the plastic becomes brittle and the O-rings corrode; both of these things create coolant leaks. If you have a coolant leak from the left side of your engine underneath the intake manifold, it could be the heater pipe on the block. If you have a coolant leak at the rear of the cylinder head, it could be the coolant pipe bolted to the cylinder head. Replacing the coolant pipe at the crankcase requires removing the intake manifold. Replacing the cylinder head coolant pipe can be done by moving the wiring junction out of the way and working blindly at the back of the cylinder head. 

When replacing, be sure to order the O-ring as well as the pipe and inspect your heater hoses, because this would be the best time to replace them. I suggest replacing both pipes at the same time. If one has failed the other cannot be far behind.

Do not remove the expansion tank cap or work on any other part of the cooling system while the engine is hot. Coolant or hot steam may escape and will scald you. To do any work on the cooling system, wait until the engine has cooled off.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability. 

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Drain the cooling system. See our tech article on cooling system draining and filling.

Remove the intake manifold. See our tech article on intake manifold replacing.

This photo shows the crankcase hose and how it can fail.
Figure 1

This photo shows the crankcase hose and how it can fail. The hose for the crankcase breather valve broke off at the nipple (green arrow). This caused a major coolant leak. If this hose is not broken on your vehicle, start by loosening this hose clamp and removing the hose from the coolant pipe.

Working at the vacuum reservoir, remove the vacuum hose with the white stripe (green arrow).
Figure 2

Working at the vacuum reservoir, remove the vacuum hose with the white stripe (green arrow).

Then pull the vacuum hose out of the holder.
Figure 3

Then pull the vacuum hose out of the holder.

Next, you have to remove the 13mm vacuum reservoir fastener (green arrow).
Figure 4

Next, you have to remove the 13mm vacuum reservoir fastener (green arrow). Once removed, pull the reservoir away from the engine and set it aside.

Working at the crankcase coolant pipe, loosen and remove both remaining hose clamps.
Figure 5

Working at the crankcase coolant pipe, loosen and remove both remaining hose clamps. (green arrows)

Then, pull both hoses off of the coolant pipe.
Figure 6

Then, pull both hoses off of the coolant pipe. (green arrows)

If you want to replace the heater hose that runs to the coolant pipe, loosen the clamp at the heater core connection (green arrow) and remove hose.
Figure 7

If you want to replace the heater hose that runs to the coolant pipe, loosen the clamp at the heater core connection (green arrow) and remove hose. This photo shows a close up view of the bottom of the heater core connections.

Next, remove the two 10mm coolant pipe fasteners.
Figure 8

Next, remove the two 10mm coolant pipe fasteners. (green arrows)

When removing the pipe it will likely break off and leave a piece in the block.
Figure 9

When removing the pipe it will likely break off and leave a piece in the block. I like to lever at the flange with a flathead screwdriver while wiggling it out.

You can see my pipe broke, I will have to remove the broken pieces from the crankcase.
Figure 10

You can see my pipe broke, I will have to remove the broken pieces from the crankcase.

Using a small pick, carefully remove the O-ring and remaining plastic pieces from the crankcase.
Figure 11

Using a small pick, carefully remove the O-ring and remaining plastic pieces from the crankcase. Be sure not to leave anything behind, it could plug the cooling system. Once removed, clean the hole of all corrosion and rust.

Lubricate the new O-ring with clean engine coolant or dish soap before attempting to install.
Figure 12

Lubricate the new O-ring with clean engine coolant or dish soap before attempting to install.

To install the new pipe, I like to push the bottom portion into the crankcase, then using a large pry bar, gently lever the top into the crankcase.
Figure 13

To install the new pipe, I like to push the bottom portion into the crankcase, then using a large pry bar, gently lever the top into the crankcase. It can be tricky to get the O-ring to seat. Work slowly and gently, be sure the flange is flush with the crankcase before installing the fasteners. Once the pipe is installed, install and tighten the fasteners. Then install the vacuum reservoir and the remaining coolant hoses.

To replace the cylinder head coolant pipe, start by removing the E-box seal from the right side engine compartment.
Figure 14

To replace the cylinder head coolant pipe, start by removing the E-box seal from the right side engine compartment. (green arrow)

Then unclip the plastic harness retainer.
Figure 15

Then unclip the plastic harness retainer. There are a total of eight clips (green arrows). Four are shown here, the other four are on the opposite side of the panel. Once unclipped, remove the retainer from the E-box by lifting it up.

Now you can remove the wiring harnesses from the mounting points.
Figure 16

Now you can remove the wiring harnesses from the mounting points. This will allow the plastic junction above the valve cover to be moved out of your way.

Next, remove the two 10mm nuts (green arrows) for the wiring harness junction mount.
Figure 17

Next, remove the two 10mm nuts (green arrows) for the wiring harness junction mount. Then remove the mount from the firewall.

Working at the right side bulkhead, cut the wire tie securing the harness to the firewall.
Figure 18

Working at the right side bulkhead, cut the wire tie securing the harness to the firewall.

Using a bungee cord or rope, pull the plastic junction toward the radiator support and out of your way.
Figure 19

Using a bungee cord or rope, pull the plastic junction toward the radiator support and out of your way.

Working at the cylinder head coolant pipe, loosen and remove both remaining hose clamps.
Figure 20

Working at the cylinder head coolant pipe, loosen and remove both remaining hose clamps. (green arrows)

Then pull both hoses off of the coolant pipe.
Figure 21

Then pull both hoses off of the coolant pipe.

When removing the pipe it will likely break off and leave a piece in the block.
Figure 22

When removing the pipe it will likely break off and leave a piece in the block. This one always pops right out and breaks. No levering needed.

Using a small pick, carefully remove the O-ring and remaining plastic pieces from the crankcase.
Figure 23

Using a small pick, carefully remove the O-ring and remaining plastic pieces from the crankcase. Be sure not to leave anything behind, it could plug the cooling system. Once removed, clean the hole of all corrosion and rust.

Lubricate the new O-ring with clean engine coolant or dish soap before attempting to install.
Figure 24

Lubricate the new O-ring with clean engine coolant or dish soap before attempting to install. To install the new pipe, press it into the cylinder head firmly. It can be tricky to get the O-ring to seat. Work slowly and gently, be sure the flange is flush with the crankcase before installing the fasteners. Once the pipe is installed, install and tighten the fasteners. Then install the wiring harness and replace the cut zip ties. Install the hoses and tighten the fasteners. If needed, replace the coolant hoses. Install the intake manifold and other items. Fill and bleed cooling system. Once complete, double check all hose connections and check engine for coolant leaks.

Bookmark and Share
Comments and Suggestions:
david Comments: what are the torque specifications for the bolts and clamps
November 13, 2016
  Followup from the Pelican Staff:

I don’t have that info.


I would grab a repair manual. It will have the procedure, special tools and torque specs.


Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Jeff Comments: If you are replacing both plastic pipes at the same time, as the article recommends, then you don't need to do the steps described in Figures 14 through 19. With the air intake off of the engine you can remove and install the pipe at the back of the cylinder from the other side.
December 29, 2015
  Followup from the Pelican Staff: True, but as noted, they are difficult to get to and removing the intake allows more space to work. - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Privacy Statement]
 [Contact Us] [About Us] [Shipping] [Map to our Location] [Careers]

Copyright © Pelican Parts Inc.

Page last updated: Sat 12/3/2016 02:07:30 AM