DIY - MKIV Headgasket replacement
This is one of those infrequently performed, but difficult to do procedures. Usually, a headgasket will be replaced in order to lower compression for FI applications, or due to a headgasket leak. Signs of a leaky headgasket could be found by oil in the coolant, coolant in the oil, visible steam/oil leaks at the engine block interface, or results of a poor compression test. If you suspect a leaking headgasket, I *highly* recommend you perform a compression test on your vehicle (see http://forums.vwvortex.com/zerothread?id=1510186 for information).
First, some light reading. Here are a list of threads to peruse prior to performance of this DIY:
This procedure is NOT for the mechanically inept, nor for the faint of heart. You will be removing VITAL engine components. I cannot be held responsible if this DIY causes engine damage or injury!
- New headgasket (approx $45)
- New OEM head bolts (approx $50)
- New OEM gasket for the Waterpump (approx $10)
- Optional: ARP headstuds instead of OEM head bolts (approx $180)
- Optional: New valve cover gasket (approx $20)
- Optional: Permatex Copper gasket spray
- 10mm socket
- drip pan
- small blade screwdriver
- 12mm triple-square bit
Note: This procedure ran me about a full day. Make sure you set aside the appropriate amount of time based on your skill / knowledge. I HIGHLY recommend you label ALL your parts, connectors, hoses, and use lots of plastic bags for bolts and smaller parts.
i. Initial conditions
- the coolant is drained from the engine from both the block and the radiator.
- the battery is disconnected and removed per steps 1.a through 1.f of the Starter Motor Replacement DIY - http://forums.vwvortex.com/zerothread?id=2269482
- various intake pieces are removed per steps 2.a through 9 of the Transmission Removal / Replacement DIY - http://forums.vwvortex.com/zerothread?id=2703042
- the spark plug wires and engine covers are removed per steps 2 through 15 of the Spark Plug Replacement DIY - http://forums.vwvortex.com/zerothread?id=1792683
- the intake manifold and coilpack are removed per steps 1 through 16 of the Intake and Coilpack Removal DIY - http://forums.vwvortex.com/zerothread?id=2916098
- the lock carrier is moved forward per the Lock Carrier Movement DIY - http://forums.vwvortex.com/zerothread?id=2368291
- the serpentine belt and tensioner are removed per steps 4 and 5 of the Tensioner Removal DIY - http://forums.vwvortex.com/zerothread?id=1138497
If you've read this far, and you still want to move on, then great! Let's get started.
1. Start by removing the vacuum line from the Fuel Pressure regulator. Pull the rubber "T" junction away from the FPR.
2. Slide the rear knock sensor out of its bracket, and disconnect it from the connector. It is located on the passenger's side, at the rear of the engine.
3. Remove the rear knock sensor bracket by unscrewing the 10mm bolt holding the bracket to the block.
4. Depressurize the fuel lines by performing steps 3 and 4 of the Fuel Filter removal DIY - http://forums.vwvortex.com/zerothread?id=1276409. You only need to disconnect the connector towards the front of the filter. Be sure to have a drip pan below the filter to catch the gasoline that spills out.
5. Place some paper towels near the fuel feed line. Then press the small tab on the feed line, and pull up on the line. It should come apart, and spill some gasoline on your paper towels.
6. Repeat step 5 for the fuel return line.
7. When both lines are removed, cover them with tape to prevent foreign material entry.
8. Using the Fuel Line / Injector removal DIY as a guide ( http://forums.vwvortex.com/zerothread?id=2975414 ) remove the fuel rail from the cylinder head.
Removing components from the cylinder head
9. Remove the line connecting the intake to the lower manifold. This should come right out by pulling hard.
10. Locate the solenoid valve near the SAI pump. There are actually two solenoid valves down by the SAI pump; one is for the intake shifter rod changeover, and the other one goes to the Kombi valve. You want the solenoid with the lines that go to the Kombi valve. Remove the solenoid from its carrier.
11. Next, you want to disconnect the vacuum line that goes from the solenoid to the Kombi valve. This is really difficult to do, so I just cut the line and put a small coupler between the two ends. Here is a picture of the line with the head in the air.
12. Now you want to remove the corrugated plastic line that connects the air filter housing to the SAI pump. I don't have any good pictures of this, but the hose you want to remove is the one above the coilpack in this picture here:
13. Remove power from the SAI pump by disconnecting the power connector.
14. Now remove the valve cover and set the engine to TDC by performing steps 1-9 of the Timing Chain DIY - http://forums.vwvortex.com/zerothread?id=1264409.
15. Remove the coolant hose that connects the engine block to the heater core using vise-grips or pliers.
16. Remove the tensioner and the upper timing chain cover by performing steps 10-13 of the timing Chain DIY - http://forums.vwvortex.com/zerothread?id=1264409
17. Clean the oil off of the chains and the cam gears, and mark the same location on the chains and cam gears using nail polish or white-out. This guarantees that the timing will remain the same. All the slack in the chain should be on the RIGHT side, closer to the firewall.
Note: In the following step, remove the cam timing plates. If the cams move, they could be damaged.
18. Now you want to remove ONE of the cam gears. The easiest one to remove is the one on the short cam. With a 24mm wrench (or open-end wrench) hold the flat spots in the cam and impact the cam gear bolt off. I suppose you could use a long breaker bar, but there is a much greater likelihood that the engine will move off TDC.
19. With the bolt removed, remove the cam gear by wiggling it back and forth on the sides. Leave the chain on the cam for now. When the cam is fully removed, tie up the chain so it does not fall into the engine. This would suck.
20. Remove the upper tensioner guide rail by removing the two bolts holding the rail in. Then pull the rail up and out towards the front of the car.
21. Using the Thermostat Removal DIY as a guide ( http://forums.vwvortex.com/zerothread?id=2385488 ), disconnect the temperature sensor and the various hoses connecting to the thermostat housing. Then, remove the thermostat housing.
22. With the thermostat housing removed, the side of the engine should look something like this:
23. Remove the oil dipstick by pulling straight up on the shaft. It should come out easily.
24. Remove the exhaust nuts that connect the exhaust manifold to the downpipe using step 7 of the 12V Downpipe removal DIY - http://forums.vwvortex.com/zerothread?id=2798484.
Removing the head
Note:You are now at the point where you are ready to remove the head. Make SURE that everything is disconnected from the head, because if you lift the head with something still connected, you may break something or drop the head.
25. Using the loosening order shown below, loosen the 20 head bolts that hold the cylinder head to the engine block. An impact wrench is *amazingly* useful here. The correct size is a 12mm triple-square bit. I used 3 passes to remove the bolts:
1) The first pass is to just break the bolts free.
2) The second pass is to unscrew the bolts until slightly loose.
3) The last pass is to fully remove the bolts.
Make SURE you bag and label EVERY bolt. There are three different sizes, and you need to put the right bolt into the right hole.
26. Now that the bolts are removed, lift the head off the block. Yeah, right. The head probably weighs around 50-60 pounds. Since I do all my work by myself, I used a series of wood blocks as wedges (like the ancient egyptians!!) to lift the head up into the air. When it cleared the front carrier, I lifted it up fully and set it on its side.
27. With the head removed, inspect the cylinders and walls. I was amazed how little carbon buildup there was, even after 180k miles!! You can even see the cross-hatch on the cylinder walls!
28. Locate the two alignment dowels for the cylinder head. They may be in the block or the head, but remove them. You will re-install them later.
29. With the dowels removed, lift straight up on the headgasket. It should come right out.
Cleaning mating surfaces
30. With the head removed, thorougly clean all mating surfaces. I used a scrub pad and some 600 grit sandpaper. Occasionally, I would vacuum out the debris. Here is the result of cleaning the surface.
31. Next, cover up all the oil passages with some kind of tape. This is to prevent entry of any foreign material.
32. Pour some kind of solvent into the top of the pistons that are the highest up. I used seafoam, and let it soak for 10-15 minutes.
33. Next, I used a dremel with a wire brush on the end on low speed to clean off all the carbon. With the seafoam sitting in the chamber, it came right off.
34. In order to get the other cylinders, you will have to rotate the engine off TDC. After vacuuming out EVERY cylinder, coat each cylinder wall lightly with new oil. Then crank the engine clockwise to bring a new set of cylinders to the top. Make SURE you return the engine to TDC with the #1 cylinder fully up when you are done!!!!!
35. This step is not required unless you are installing a headgasket spacer to lower compression. Spray both sides of the headgasket with permatex copper spray. This will ensure a good seal between the spacer and the head / block.
36. Reinstall the dowels you removed on step 28.
37. Now, reinstall the new headgasket. If you can read the lettering in the upper right hand corner of the headgasket, you have it installed the correct way.
38. Using one of the old, long bolts, screw the bolt fully into each hole in the block, cleaning the bolt off as you remove it. This will remove any foreign debris from the bolt holes. I also blew compressed air into the holes to dry them off.
39. Lightly oil the inside of the cylinder walls one last time before you put the head back.
Installing the head
40. This is very tricky, especially by yourself. I didn't take any pictures, but I will explain what I did. Using the three longest bolts, I cut the heads off and installed the bolts in three of the four corners. These bolts provided alignment for me to lower the head down. Once the head was down, I removed the long bolts.
41. Using your old bolts that you hopefully labeled, hand-tighten the new bolts into the holes using the diagram in step 25. This ensures that the right bolt goes in the right hole. I put a very slight amount of assembly lube on the bolts to assist in engagement.
42. Using the tightening order shown below, make three torque passes on the head bolts:
1) The first torque pass should be 50 Nm (37 ft-lb).
2) The second pass should be an additional 1/4 turn.
3) The last pass should be an additional 1/4 turn.
43. The headgasket is now installed with the cylinder head tightened. I hesitate to say "Installation is the reverse of removal", but that is pretty much the case. The camshaft sprocket bolt needs to be torqued to 100 Nm (74 ft-lb). Follow the instructions above in reverse. Here are some things to note:
- Make sure the engine is at TDC and the cam plates are aligned to guarantee timing is correct before you install the chain and the cam sprocket.
- The cam sprocket bolt needs to be torqued to 100 Nm (74 ft-lb)
As always, let me know with any questions. Hope this helps!