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    
 >  >
Head Gasket Replacement
 
Bookmark and Share

Pelican Technical Article:

Head Gasket Replacement

Nick Czerula

Time:

12 hours12 hrs

Tab:

$150 to $250

Talent:

*****

Tools:

Set of sockets hex, Allen, Torx, wrenches (19mm, 32mm), screwdrivers, camshaft timing tools, torque wrench, angle finder, plastic clean up tool. BMW tools; 11 2 300, 11 3 240,

Applicable Models:

BMW Z3 (1996-02)

Parts Required:

Head gasket kit, coolant pipe and O-rings, spacer sleeve, timing cover gaskets

Hot Tip:

Work with a cool engine.

Performance Gain:

Repair oil and coolant leaks

Complementary Modification:

Replace engine coolant pipes

The cylinder head gasket seals the seam between the top component of the engine, the cylinder head, and the bottom end, cylinder block or crankcase. It is responsible for sealing the combustion chambers, the oil passages and the coolant away from each other. The sealing surfaces of the cylinder head and cylinder block are machined very precisely to be absolutely flat. The head gasket is designed to fill any irregularities that the machining left behind. In addition, the metal parts expand and contract due to thermal changes, and they do so at different rates because they are made of different metals. This means that the head gasket is required to allow some slippage and to fill distortions between the sealing surfaces even though the entire assembly is bolted together at very high torque.

Cylinder head bolts are designed to stretch and stay stretched when torqued and are therefore one-time-use bolts. They are threaded into the soft alloy of the cylinder block, which, due to the thermal stresses of the engine, may lose its ability to hold the bolts tightly.

Therefore, with aging and mileage, the head gasket may fail. When this happens, you could have engine overheating, oil and coolant mixing along with a poor running motor. On BMW Z3 models it is often the case that you cannot simply replace the head gasket; faulty threads in the cylinder block make this a useless repair. Before repairing a faulty head gasket, attempt to retorque the cylinder head bolts. See our tech article On Cylinder Head Bolt Testing. If the bolts will not tighten, the block is faulty as well. Not all hope is lost, as you can repair the thread holes with time-serts, which work quite well. However, most times if the cylinder head bolt threads are faulty it is better to go with a used lower mileage engine. 

To replace the head gasket, you need a handful of special tools including but not limited to:

  • Camshaft timing tools
  • Torque wrench
  • Angle finder
  • Plastic clean up tool
  • Standard hand tools 

Read through the entire procedure before beginning. Be sure this is not above your skill level, as engine damage can occur if engine timing is not correct.

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.

Be sure to have your cylinder head professionally cleaned and pressure tested before reinstalling. 

To begin, complete the following procedures:

  1. Drain the engine oil and coolant.
  2. Disconnect the negative (-) battery cable. See our tech article on battery replacing for connection notes.
  3. Remove the engine cover. See our tech article on removing engine covers.
  4. Remove the valve cover. See our tech article on valve cover gasket replacing.
  5. Remove the engine cooling fan and shroud. See our tech article on engine cooling fan replacing.
  6. Remove the thermostat. See our tech article on thermostat replacing.
  7. Remove the coolant hoses from the rear of the cylinder head at the plastic pipes. See our tech article on coolant pipe replacing.
  8. Remove the intake manifold. See our tech article on intake manifold replacing.

Working at the secondary air check valve, unclip and open the upper hose clamp (green arrow) using a flathead screwdriver.
Figure 1

Working at the secondary air check valve, unclip and open the upper hose clamp (green arrow) using a flathead screwdriver.

Next remove the three 10mm secondary air check valve mounting bracket fasteners (green arrows).
Figure 2

Next remove the three 10mm secondary air check valve mounting bracket fasteners (green arrows).

Then remove the secondary air valve from the cylinder head by rotating it out of secondary air pipe.
Figure 3

Then remove the secondary air valve from the cylinder head by rotating it out of secondary air pipe.

Remove secondary air check valve vacuum hose from plastic bracket.
Figure 4

Remove secondary air check valve vacuum hose from plastic bracket. Then lay secondary air check valve in left side of engine compartment and out of your way. You can remove it completely from engine, I prefer to just store it semi-assembled.

Working at the front of the cylinder head, remove eleven 10mm upper timing cover fasteners (green arrows), then remove the timing cover from cylinder head by pulling straight off.
Figure 5

Working at the front of the cylinder head, remove eleven 10mm upper timing cover fasteners (green arrows), then remove the timing cover from cylinder head by pulling straight off. Remove exhaust manifold. See our tech article on exhaust manifold replacing. You can leave the manifold on for now, but it will have to be removed when the head is sent to a machine shop. Using a 22mm socket on the crankshaft pulley fastener, rotate engine clockwise.

Rotate engine clockwise until the first (cylinder #1) camshaft lobes point just about up (green arrows).
Figure 6

Rotate engine clockwise until the first (cylinder #1) camshaft lobes point just about up (green arrows). This brings engine to cylinder #1 TDC position. This is the first step in locking the engine timing position.

The square blocks on the ends of the camshafts have holes bored into them, these holes should also point up when at TDC #1.
Figure 7

The square blocks on the ends of the camshafts have holes bored into them, these holes should also point up when at TDC #1.

Next you are going to remove the dust plug from crankcase.
Figure 8

Next you are going to remove the dust plug from crankcase. It is located below engine, inside of mounting reinforcement. This photo shows the plug (green arrow), it is just behind the starter motor. Remove plug from crankcase. The dust plug can become stuck over time. If needed, pry out using a flathead screwdriver.

Next, install crankshaft locking pin tool (11 2 300) (green arrow) into the hole dust plug was removed from.
Figure 9

Next, install crankshaft locking pin tool (11 2 300) (green arrow) into the hole dust plug was removed from. When installing tool, push in until it bottoms out. Slowly rotate engine until pin drops in about 12mm further. Once the tool is installed, confirm the crankshaft can no longer be rotated. Follow the instructions that came along with your special tool kit to ensure proper use.

Install camshaft locking jig (11 3 240) at rear of camshafts.
Figure 10

Install camshaft locking jig (11 3 240) at rear of camshafts. Jig should slide down onto square bosses on end of camshafts, then secure together. Follow the instructions that came along with your special tool kit to ensure proper use.

Using a 19mm wrench, remove the timing chain tensioner located at the right side of the engine (green arrow).
Figure 11

Using a 19mm wrench, remove the timing chain tensioner located at the right side of the engine (green arrow).

Working at right side timing chain guide rail, remove the 5mm Allen fastener.
Figure 12

Working at right side timing chain guide rail, remove the 5mm Allen fastener. (green arrow)

Then using a flathead screwdriver, loosen the guide rail bushing two turns.
Figure 13

Then using a flathead screwdriver, loosen the guide rail bushing two turns.

Working at the top of the camshaft sprockets, remove upper timing chain guide rail 5mm Allen fasteners (green arrows), then remove guide rail from cylinder head.
Figure 14

Working at the top of the camshaft sprockets, remove upper timing chain guide rail 5mm Allen fasteners (green arrows), then remove guide rail from cylinder head.

Working at camshaft sprockets, remove camshaft sprocket fasteners (green arrows).
Figure 15

Working at camshaft sprockets, remove camshaft sprocket fasteners (green arrows).

Next, remove the camshaft impulse wheel (green arrow) by lifting it off the right camshaft.
Figure 16

Next, remove the camshaft impulse wheel (green arrow) by lifting it off the right camshaft.

Next you have to remove the camshaft sprockets from the camshaft.
Figure 17

Next you have to remove the camshaft sprockets from the camshaft. I like to zip tie the timing chain onto the sprocket, this keeps the sprockets and chains in the same position that I removed them in and helps when reassembling. Once the sprockets are removed, lay them down at front timing cover.

We are now at the part where the cylinder head bolts can be removed (green arrows).
Figure 18

We are now at the part where the cylinder head bolts can be removed (green arrows). Remove all ten E12 inverted Torx bolts from the cylinder head. Start in the center of the cylinder head and work your outward alternating side to side.

Once the bolts are removed, I remove the washers with a magnet (green arrow).
Figure 19

Once the bolts are removed, I remove the washers with a magnet (green arrow). With help from an assistant, lift the cylinder head off the crankcase. Guide the timing chain rails out of head as you lift it up, checking for snagged items.

Remove the old head gasket from the engine.
Figure 20

Remove the old head gasket from the engine.

Next remove the spacer sleeve from the crankcase (green arrow).
Figure 21

Next remove the spacer sleeve from the crankcase (green arrow). It is located between cylinders 2 and 3. Remove all of the old head gasket material from the block. I like to use the green 3M clean up discs and a plastic scraper. They are safe to use on engines and does a great job of cleaning it up. Do not mar or scratch the surface while cleaning. Once the head is removed, send it to a machine shop to be cleaned and pressure checked for cracks and warping.

Check the block deck for warping.
Figure 22

Check the block deck for warping. A maximum of 0.05mm is allowed. Use a straight edge bar designed for checking engine straightness and a feeler gauge. This photo shows a deck being checked on a 6-cylinder engine, the procedure is similar on 4-cylinders.

Once the block surface is cleaned and checks out OK.
Figure 23

Once the block surface is cleaned and checks out OK. Install a new spacer sleeve into crankcase (green arrow).

Install camshaft locking jig (11 3 240) at rear of camshafts.
Figure 24

Install camshaft locking jig (11 3 240) at rear of camshafts.

Install new timing cover profile seals.
Figure 25

Install new timing cover profile seals. Be sure they are properly inserted into groove.

Place new cylinder head gasket on the block.
Figure 26

Place new cylinder head gasket on the block. Be sure both alignment dowels are in good shape. Lower head back onto engine, as you guide timing chain up through timing cover area.

With help from a friend, lower cylinder head onto the block.
Figure 27

With help from a friend, lower cylinder head onto the block. Guide timing chain rails up and inside of front of cylinder head, they tend to get hung up. Be sure head gasket does not slip when installing. I opted to preinstall the exhaust manifold before installing the cylinder head. If I did not have help around it would have been difficult to align the cylinder head while lowering with the manifold attached. I do not suggest doing this if you are working alone.

Once installed, check that cylinder head gasket is properly installed and visible between block and cylinder had on left side of engine.
Figure 28

Once installed, check that cylinder head gasket is properly installed and visible between block and cylinder had on left side of engine. Also check that the rear timing cover gasket (green arrow) did not slip. Install new cylinder head bolts into the cylinder head. Lightly coat the threads with clean engine oil and install finger tight. Do not reuse old cylinder head bolts.

My head gasket came with the torque specs along with the tightening sequence.
Figure 29

My head gasket came with the torque specs along with the tightening sequence. This was quite handy. The cylinder head bolts are torqued in three stages.

Stage 1: Start by torqueing the head bolts to 30 Nm (22 ft-lb).
Figure 30

Stage 1: Start by torqueing the head bolts to 30 Nm (22 ft-lb). Start in the center and work your way outward, alternating side to side. Use the previous photo as a reference. After the initial torqueing, you will have to torque the bolts a total of two more times. Each time rotating the head bolt an additional 90°. Stage 2: use an angle finder and tighten the head bolts an additional 90°. Start in the center and work your way outward, alternating side to side. Stage 3: use an angle finder and tighten the head bolts an additional 90°. Start in the center and work your way outward, alternating side to side.

Lift camshaft timing chain with sprockets onto camshafts.
Figure 31

Lift camshaft timing chain with sprockets onto camshafts. Then install the camshaft sensor impulse wheel. Next, install fasteners finger tight. Next, install the timing chain tensioner and tighten it to 40 Nm (30 ft-lb). It should apply tension to the timing chain and remove all the slack. At this point the crankshaft locking pin and camshaft locking tool should have been in place. With the slack removed from the timing chain, tighten the timing chain sprocket fasteners to 15 Nm (11 ft-lb).

Remove the crankshaft locking pin and the camshaft locking tools.
Figure 32

Remove the crankshaft locking pin and the camshaft locking tools. Rotate the engine two full rotations and confirm that the first camshaft lobes point up (green arrows). Reinstall locking tools and confirm engine is properly timed. Reinstall upper timing chain guide rail at cylinder head.

Tighten the guide rail bushing two turns (the same amount you loosened it).
Figure 33

Tighten the guide rail bushing two turns (the same amount you loosened it). Be sure timing chain guide rail is straight and there is no lateral pressure on it. Once the bushing is at the proper depth, install and tighten the 5mm Allen fastener.

Then install front timing cover with a new gasket.
Figure 34

Then install front timing cover with a new gasket. If needed, cut old gasket out at bottom edges (green arrows). Install thermostat and secondary air check valve. Install the intake manifold. Install the exhaust manifold. Install the valve cover. Install coolant hoses. Install the engine cooling fan and shroud. The remainder of the reassembly steps are reverse of removing. Be sure to replace engine oil and engine coolant when done. I always pull the engine oil drain plug after a head gasket before I fill the engine with oil. This way I can drain any excess oil or coolant that may have leaked into the crankcase during the procedure. Bleed cooling system and check for leaks.

Bookmark and Share
Comments and Suggestions:
Waco joe Comments: My daughter overheated my Z3 2.8 six cylinder engine.I let it cool twenty hours, and filled radiator which was dry,and cranked it. It shot water up from radiator filler hole and killed engine. Is that most likely head problems? No oil n water n water n oil.Should I pressure test radiator or what? HELP! Im n over my head!
September 1, 2016
  Followup from the Pelican Staff: I would pressure test the cooling system. If the system will not hold pressure and there are no external leaks the head gasket may be faulty. if it holds pressure, you may have a faulty thermostat or water pump. - Nick at Pelican Parts  
unlimetedm44 Comments: hi are these timing adjustments the same for a 1.9l 97 bmw 318ti m44 engine ???? thank you
December 21, 2015
  Followup from the Pelican Staff: It should be similar. - Nick at Pelican Parts  
Dennis Comments: hi

do you have this for a bmw e36 320i 24V?
because i cant find it.

thx

Best regards.
Dennis
November 20, 2015
  Followup from the Pelican Staff: Try this:

http://www.pelicanparts.com/bmw/techarticles/101-Projects-17-Head-Gasket/101-Projects-17-Head-Gasket.htm - Nick at Pelican Parts
 
tonic Comments: What to do a after setting the timing?
July 5, 2014
  Followup from the Pelican Staff: On what vehicle? - Nick at Pelican Parts  
tonic Comments: my bmw e90 320i keeps jumping time after setting the timing after trying to start. How long should I leave it to idle after installing the vanos
July 5, 2014
  Followup from the Pelican Staff: I would check if the tensioner and guides are in good shape. I don;t see why the timing would jump repeatedly otherwise. - Nick at Pelican Parts  
Dallas Comments: Hi

I have a e36 318is, my alternator belt snapped on a long drive home, I have replaced this then relised I had to replace water connector and while I was there I put new thermostat in, I have been flushing the system for four hours now stop an carnt be merplederped any more, I have steam in the coolant res and we'll hoping it isn't a head gasket, if it is do I need to mess about with timing to replace the gasket

Thanks neil
June 1, 2014
  Followup from the Pelican Staff: It could be a faulty head gasket. I would start be bleeding the cooling system. If the engine overheats after bleeding, pressure test the cooling system. If the system will not hold pressure and has no external coolant leak you may have a faulty head gasket. You will have to set the timing when replacing the head gasket.- 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 02:07:48 AM