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Radiator Replacement
 
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Pelican Technical Article:

Radiator Replacement

Nick Czerula

Time:

3 hours3 hrs

Tab:

$250

Talent:

****

Tools:

Set of sockets (8mm, 10mm), wrenches (22mm, 30mm), screwdrivers

Applicable Models:

BMW Z4 Convertible (2003-06)
BMW Z4 Coupe (2006)

Parts Required:

Radiator, hoses, engine coolant, radiator foam seals

Hot Tip:

Work with a cool engine

Performance Gain:

Car will cool down again

Complementary Modification:

Change expansion tank, radiator hoses

Maintaining the cooling system so that the engine does not overheat is a significant step toward getting engine longevity. There are many components in the BMW Z4 cooling system:

  • Radiator and coolant overflow tank
  • Belt driven coolant pump bolted to the front of the engine block
  • Electric cooling fan attached to front of radiator - The cooling fan is controlled by the engine control module (ECM) via an output final stage.
  • 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

When the radiator begins to fail, you'll notice that the car tends to overheat at high engine speed, such as driving on the highway. When you accelerate, the engine temperature rises, and when you idle it returns to normal range. Now, this is not always indicative of a failing radiator, but a good starting point.

The plastic side tanks of the radiator can crack, causing major loss of engine coolant. In that case you have to replace the radiator.

The radiator fins may also become plugged with debris causing the vehicle to run hotter than normal. Removing the radiator and flushing the fins with water can remedy this.

In this article, I'll go over the steps involved with replacing the radiator on BMW Z4 models. Be sure to work with a cool engine and confirm the cooling system lacks pressure before opening cooling system. On the Z4, the main difference in radiator replacement for the 6-cylinder is the lack of the expansion tank on the radiator.

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.

To avoid marring the paint and trim, work with a plastic prying tool or wrap a screwdriver tip with masking tape before prying out body or interior items.

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 cooling fan. See our tech article on radiator cooling fan replacing.

When the radiator (green arrow) begins to fail, you'll notice that the car tends to overheat at high engine speed, such as driving on the highway.
Figure 1

When the radiator (green arrow) begins to fail, you'll notice that the car tends to overheat at high engine speed, such as driving on the highway. When you accelerate, the engine temperature rises, and when you idle it returns to normal range. Now, this is not always indicative of a failing radiator, but a good starting point.

Working at the top of the radiator support, remove eight Phillips head screws (red arrows and the two T25 Torx fasteners (green arrows).
Figure 2

Working at the top of the radiator support, remove eight Phillips head screws (red arrows and the two T25 Torx fasteners (green arrows).

This photo shows a close up of one of the eight Phillips head screws (green arrows) with the plastic anchor (inset) and theT25 Torx fastener (red arrows).
Figure 3

This photo shows a close up of one of the eight Phillips head screws (green arrows) with the plastic anchor (inset) and theT25 Torx fastener (red arrows).

Lift the radiator support trim in the direction of the red arrow to remove it.
Figure 4

Lift the radiator support trim in the direction of the red arrow to remove it.

The radiator is now uncovered (red arrow).
Figure 5

The radiator is now uncovered (red arrow).

Working at the left side of the radiator, disconnect the upper radiator hose (green arrow) and the vent line (red arrow).
Figure 6

Working at the left side of the radiator, disconnect the upper radiator hose (green arrow) and the vent line (red arrow).

Use a flathead screwdriver to lift the hose spring locks (red arrows) up until they stop.
Figure 7

Use a flathead screwdriver to lift the hose spring locks (red arrows) up until they stop.

Pull the hose off the radiator toward the engine (red arrow).
Figure 8

Pull the hose off the radiator toward the engine (red arrow). If the hose is stuck, wiggle it up and down as you pull it off. Work gently.

Once the hose is off the radiator, remove the vent line (red arrow) from the hose.
Figure 9

Once the hose is off the radiator, remove the vent line (red arrow) from the hose.

To replace the upper hose: using a flathead screwdriver, loosen the upper radiator hose clamp (red arrow).
Figure 10

To replace the upper hose: using a flathead screwdriver, loosen the upper radiator hose clamp (red arrow). Once loose, slide the hose clamp away from the radiator. Then disconnect the hose by pulling it straight off thermostat the housing.

Working at the right side of the radiator, disconnect the lower radiator hose (green arrow).
Figure 11

Working at the right side of the radiator, disconnect the lower radiator hose (green arrow). Use a flathead screwdriver to lift the hose spring lock (red arrow) up until it stops. Pull the hose off the radiator toward the engine. If the hose is stuck, wiggle it up and down as you pull it off. Work gently.

Remove the rubber seal from the top of the radiator by pulling up (green arrow).
Figure 12

Remove the rubber seal from the top of the radiator by pulling up (green arrow).

Working at the top of the radiator, remove the T25 Torx fastener (red arrow).
Figure 13

Working at the top of the radiator, remove the T25 Torx fastener (red arrow).

Lift the radiator up slightly and check for snagged hoses or electrical harnesses.
Figure 14

Lift the radiator up slightly and check for snagged hoses or electrical harnesses. Then lift the radiator up (red arrow) and remove it. Note the debris in the cooling fins (green arrow). If you have an overheating issue, debris trapped in the radiator will decrease the cooling capacity of the radiator.

To replace the lower hose: using a flathead screwdriver, loosen the lower radiator hose clamp (red arrow).
Figure 15

To replace the lower hose: Using a flathead screwdriver, loosen the lower radiator hose clamp (red arrow). Once loose, slide the hose clamp away from the radiator. Then disconnect the hose by pulling it straight off the thermostat housing. Reverse these steps to install the new radiator. Insert the new radiator into the radiator support. Install the fasteners and radiator hoses. Install the cooling fan, and fill and bleed the cooling system. Once complete, check the cooling system for leaks, and top up the cooling system. 


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Comments and Suggestions:
Hassam Comments: Bmw z4 3.0 2003,

There are 2 high pressure aluminum hoses in the left part of the radiator, what are those? How do I removed them?
May 26, 2017
  Followup from the Pelican Staff: Can you share a photo? If they are A/C lines, first you have to evacuate the A/C system. - Nick at Pelican Parts  
Chaps Comments: I installed a new radiator support as all the front end of car was damaged, now I need to install the items I mentioned, but nothing gives
March 20, 2017
  Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799. Give them the year and model of your vehicle and ask them to email you the relevant pages from the parts book.
Use those pages to see if anything is missing. - Nick at Pelican Parts
 
chaps Comments: Hello i am trying to put back in the electric fan, radiator and condenser on a 2005 Z4 and i can't figure it out, don't know if i am missing parts or what
March 19, 2017
  Followup from the Pelican Staff: I am not sure, please show me a picture of the issue you're having, I'll do my best to help out. - Casey at Pelican Parts  

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Page last updated: Tue 9/19/2017 03:16:30 AM