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BMW 645 Coolant leak repair (Cap with Seal Repair and Expanding Coolant Pipe Installation w Pics)

By Michael R. Brown

(Estimated time to complete the job is 6-8 hrs)

• List of parts needed below.

BMW PART P/N PRICE QTY

SECONDARY AIR PIPES (pressure hose assy Y-Pipe) 11 72 7 508 270 $55.28 1

SECONDARY AIR PIPES 1-4 11 61 7 547 185 $53.17 1

SECONDARY AIR PIPES 5-8 11 61 7 547 186 $53.17 1

VENT PIPE( TO HEADS from coolant container) 17 12 7 542 540 $66.27 1

2 LOWER INTAKE SEALS (Intake Manifold Gasket) 11 61 7 521 181 $68.80 2

MISC O-RINGS (Water Pump to Heater Return Pipe ) 11 51 7 507 717 $5.08 1

MISC O-RINGS (O-Ring Water Pipe/Water Pump) 11 53 1 710 048 $6.60 2

COOLANT BMW 82 14 1 467 704 $19.95 1

Cap with Seal 11 14 7 507 278 $72.68 1

Hex bolt with washer (Cap with seal) replacements 07 11 9 905 400 $9.90 12

Profile gasket 11 51 7 508 535 $9.06 1

Return Pipe 11 51 1 439 976 $20.44 1

Feed Pipe 12 31 1 439 988 $17.88 1

O-ring 07 11 9 903 596 $6.10 2

Cooling Pipe Kit (Expanding) (ALL German Auto)760-738-4626

$644.00 1

Note: Price quotes are from the link below and would be much

higher if you purchase the parts from the dealer. You may be able

the find the parts cheaper at other sites too.

http://www.bmwmobiletradition-online.com/index.wws?cookieID=32fa031e4a11ae4899cd2fcde5b94ff3

• Tools needed

- Zip lock bags (box) for nuts, bolts, etc. (Mark the bags to speed up identifying them later.

- Torx socket Set $20 (Wal-Mart)

- Hex socket set (Metric) $20 (Wal-Mart)

- metric socket set (deep) $20

- socket extensions set $10 (Wal-Mart)

- vacuum w/ small diameter attachment

- feeler gauge $5 any automotive store

- telescoping mirror $5 any automotive store

- telescoping magnet $3 any automotive store

- recipicating saw w/ metal cutting blade $55 (Home Depot/Loews)

- small seal pick $10

- Automotive grease (not pictured)

- Cordless drill or ratchet (speeds up the job)

- Drill socket adapter (Wal-Mart) $10

- Phillips screwdriver (not pictured)

- Jack and Jack Stands or Vehicle ramps ( not pictured)

(Warning!!!! Never get under a vehicle supported by only a jack, because, the jack could fail and the vehicle can fall on you and injure or kill

you!!!!!!!!!!!! Always use jack stands!!!!!!!!!!!

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Let’s get started

1. Disconnect battery in the trunk. (Negative terminal only)

2. Jack up the car and remove the front under cover.

3. Remove the gas cap (releases pressure in fuel system)

4. Remove underbody cover (Front only)

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3/8 Extensions

Feeler

gauge

3/8 Metric Short and Deep well

Sockets

3/8 Ratchet

Metric Hex set

Small Pick tool

Telescoping

mirror

Telescoping magnet Torx set

Reciprocating Saw w/

metal cutting blade

Drill w/ 3/8 socket

adapter

5. Remove the cap on the coolant reservoir and

drain the coolant.

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Loosen the

red cap and

drain the

coolant

6. Remove the 4 torx screws and remove top

engine cover

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7. Detach the small vacuum line on the intake tube and loosen the intake

tube clip next to the sensor.

8. Disconnect sensor, unclip and remove the air box

top cover with the intake tube assembly

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9. Remove 3 torx screws from the lower air box

housing, slide out and remove the housing

10. Unclip cabin filter housings, turn plastic

13mm screw and remove cabin filter on driver

side)

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11. Unclip cabin filter housings, turn

plastic 13mm screw, disconnect sensor

and remove cabin filter on passenger

side)

12. Pull up on center cabin filter housing

support brace, slide to driver’s side and

remove

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14. Remove 2 torx screws holding

cabin filter housing to strut tower

driver’s side

13. Remove torx screw holding cabin

filter housing to strut tower passenger

side

15. Turn these plastic nuts counter clockwise a quarter turn to remov

side first).

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15. Turn these plastic nuts counter clockwise a quarter turn to remove the cabin filter housing and weatherstrip (remove driver’s e the cabin filter housing and weatherstrip (remove driver’s

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16. Remove the 6 large torx screws and remove

the strut brace

17. Pull up and lift off the side engine covers (they just snap out).

They are snapped into 2 rubber grommets each side.

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18. Unclip the fuel line by removing the

grey clip, pushing the black piece back and

slide out the fuel line Note: Catch fuel

with a cup or small pan. Also, take a zip-

lock bag and place over line with a rubber

band to catch fuel that come out later.

19. Remove 4 screws on

throttle body, disconnect

sensor and slide off

throttle body (clean it

while you have it off with

carburetor cleaner.

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Note: these will most likely break when removing them. The old 1 piece design was replaced by two pipes. You may have

either 1 pipe with 4 connection or 2 pipes with 2 connections. (shown in the pics below)

20. Unclip the 2 sensors on the thermostat housing.

Pull up on the wire and slide off. Note: After

disconnecting the connector, push the wire back down

to keep from losing the wire.

21. Carefully!!! Squeeze the connections, wiggle until they come

off, and then remove the vent pipe(s) from the intake manifold to

each valve cover. Note: I show both types in my picture.

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Old 1 piece design

New 2 piece design (these are re-useable and have

heat protection padding on them)

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Slides off right here

22. Squeeze and remove

vent pipe on the side of the

throttle body opening on

the intake manifold and

slide the other end off the

retaining support. (front of

driver's side valve cover)

23. Using a feeler gauge, gently unclip the round electrical

connector on the (front) of the wiring harness from each

side. It should slide right out. (See pic below for removal)

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Gently slide the feeler gauge under the clip and pull on

the connectors rubber boot and it should come right out.

24. Unclip and remove 2 electrical connectors from

wiring harness. (Passenger’s side) Squeeze and pull

out the round ones. Pull wire up on rectangular

connector and pull the connector off.

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25. Unclip and remove 2 electrical connectors

from wiring harness. (Driver’s side) Squeeze

and pull out the round ones. Pull wire up on

rectangular connector and pull the connector

off.

Supports

26. Remove 4 torx screws on

top of each side of wiring

harness and remove the two

supports

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27. Unclip connectors each side and remove

the 8 hex screws attached to the servo motors

(4 each side)

Remove servo motors from each side. (Mark them to insure you

install them back on the correct side. They should pop out once

the screws are removed, if not, just screw them out. (do not drop

them)

Also, stuff clean rags in the holes or cover them to prevent

anything from falling in holes.

28. Lift up on the wiring harness

to release it and move it outward

on each side to access intake

nuts.

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29. Turn a quarter or a turn,

lift up and disconnect the

round connectors on the rear

valve cover to the wiring

harness on both the driver’s

and passenger’s side

30. Lift out the 3 plugs

on the passenger side to

the ECU box.

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31. Remove the screws to ECU

Cover (I only show 1 screw but

there are 4 or 5),

Slide the white triangle to

unlock and remove the ECU

cover.

32. Loosen and remove (10 each)

11 mm nuts holding down the

intake manifold on both sides. You

may need a deep well 11 mm if

your sockets are short.

(Use a magnet to catch the nuts

so they do not fall down under the

engine)

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Note: The manifold should come right out by pushing the cable and hose down in front of the intake

manifold.

33. . Locate the wires on the driver’s side wiring harness and pull them out of the clip to give you

some slack on the wiring harness to remove the intake manifold.

Note: This picture is just to show you the wires (don’t pay attention to anything else, you are

further alone)

34. On the front of the intake manifold,

unclip and pull the cable down going to

each side’s coils.

35. With the help of a second

person, lift the intake manifold up

and pull forward 2-3 inches to

disconnect two remaining

connectors on the back of intake

manifold. Now lift up to clear the

bolts and remove the intake

manifold slowly.

Note: There are two wiring

harness connectors that need to

be disconnected on the rear of

the intake manifold. You can

unhook them once you pull the

intake manifold forward about 2

inches

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Here is a picture of the intake

manifold out of the car.

36. Remove the hose from the coolant

reservoir to each side of the block (it

might break but, you have the

replacement) The Y connecting the hoses

is plastic.

To coolant

reservoir

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37. Stuff rags in the 8 intake holes on

the block to prevent dirt etc.. from

falling in to the engine and vacuum

the area around the holes.

* Follow the cable to front

connector not pictured

38. Squeeze and

disconnect the Y-vent

pipe lying over the Cap

with Seal. 2 connectors

on rear and 1 in the

front (not in pic). Also

remove the hold down

clamp too.

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39. Disconnect, remove hold down

bolt and pull the aluminum pipe out of

the thermostat housing to rear.

40. Unclip and move the black

cable clips to the cap with seal

(You will re-use them)

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41. Remove 11 bolts remaining

bolts holding the cap with seal

down. (Do not reuse them because

they will break when trying to re-

tighten them after installing the

new cap with seal). The new bolts

from BMW are now steel.

42. Remove the cap with seal and

suck out or use a towel to remove

the gallon of coolant.

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* Note: If you are just replacing the Cap with seal stop here and put everything back

together in reverse order.

Note: If you are going on with the expanding cooling pipe install, follow the instructions

that came with the pipe kit or continue below. There are also 3 videos on YouTube

demonstrating the pipe installation and I suggest you review them several times before

completing the job. Here is the one from All German Auto

http://www.youtube.com/AllGermanAuto#p/a/u/0/UoCED1jyfL4

Expanding Cooling Pipe Install

43. Using a reciprocating saw cut the

OEM cooling pipe in half.

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44. Remove the rear half of

the cooling pipe

45. . Drill a hole in the front half of the

pipe and using a screw driver and a

block; pry the front half of the cooling

pipe out toward the rear.

Note: Ensure you place the seals in properly using the instructions that came with the pipe.

47. Use automotive grease on the

new seals and install them in place

of the old ones

46. Using a pick and mirror;

remove the O-ring seals from the

front and rear holes.

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Note: You are suppose to check the system for leaks before putting everything back together

but, good luck finding the special BMW tool. Also, I did not take off the water pump housing

either. You have the parts on hand if want to do it now or later.

49. Go ahead and put everything back together in reverse order. Starting with the Cap with Seal.

Lessons learned

- Do not reuse the bolts to the Cap with Seal because they are prone to break when re-

tightening them after installing the new part. Also, do not over tighten them. I tightened

them down snug with an extra quarter turn.

- Don’t forget to connect the 2 connector on the rear of the intake manifold

- Be extra carefully removing vent pipes

- Make sure the intake manifold is seated correctly (watch out for the clip on the last bolt

on the drivers side)

- When reinstalling, ensure vent pipes are fully seated. They may take a little manipulating

to get them to clip on!!! This is especially important for the Y -Vent pipe, because it is

under the intake manifold and if it is not seated properly you will have to pull the intake

manifold off again!!!

- If you get a check engine light for increased emissions and the engine idles very rough or

when you press on the gas the engine runs rough; double check your vent pipes and all

connecters.

48. Install the new pipe tight, but do

not over tighten. I tightened it as tight

as I could by hand and used a wrench to

tighten it another quarter turn. This is

how the final install should look.

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- If this happens, check all pipes connections. Once they are seated correctly the check

engine light will go out after driving for a day or so.

* Congrats!!! You have just saved $2000 on the Cap with Seal Job and $9000 on the Coolant Pipe

Job. Both of these parts fail around 80,000 to 100,000 miles and are known problems with the N62

engine. If you have any questions or you live in the Atlanta area and would like for me to complete

the jobs for you, shoot me an email at robe370@aol.com