Front crankshaft seal replacement mk4 VW ALH and BEW TDI engine

Apr 25, 2017
Front crankshaft seal replacement mk4 VW ALH and BEW TDI engine
  • Front crankshaft seal replacement ALH and BEW TDI engine

    difficulty: 4/5


    This article shows crankshaft front seal removal and replacement on an ALH engine, BEW engine similar. While not very technically difficult, seal replacement requires timing belt removal plus a few more steps. Because of the additional time and special tools required, it's rated 4/5 difficulty for the novice (but can easily be done in your driveway).

    The ALH crankshaft seal is mounted in the front engine carrier and the carrier is bolted to the engine block and oil pan. While the seal can be removed from the carrier without removing the carrier from the engine, removing the carrier facilitates the cleaning of the crankshaft, which is extremely important when installing a PTFE (Teflon) seal. Volkswagen specifies the removal of the oil pan when the carrier is removed (to ensure complete sealing upon reassembly). This procedure describes the process without removing the oil pan. The service manual (and the correct way) to replace the front or rear crank seal is to remove the oil pan before before installing the new seal. This article shows it without removing the oil pan. There's a small chance of an oil leak so follow this procedure at your own risk!

    If you wish to remove the oil pan, see 1000q: mk4 engine oil pan removal.

    The crankshaft seal drift is different if your new seal is teflon (papery feel, no spring) or rubber-spring. The original seal until around 2003 was rubber-spring and you can switch to the teflon seal without a problem. Rubber seals use guide sleeve VW tool# 2080a and is pushed in with 3265. Teflon seals may come with a guide sleeve but no drift. Teflon seals use guide sleeve T10053 and drift T10053/1. If using a teflon seal, do not use any oil to lubricate the seal. Also let it sit for at least 4 hours before starting the engine. If using a rubber seal, lubricate the lip before installing the seal.

    The pictures and article are by user mirogi.

    10mm sockets
    crankshaft counterhold tool
    timing belt tools
    crankshaft sprocket counterhold
    crankshaft drift, either T10053 or 2081a/3265 depending on seal type

    gasketmaker (Reinzosil or similar)
    degreaser and shop towels
    PTFE (teflon) crankshaft seal: VW# (038 103 085 e) or rubber crankshaft seal: VW# (054 115 147 b)

    Remove the serpentine belt. Remove the harmonic balancer from the end of the crankshaft.

    The bolt that attaches the timing belt gear to the crankshaft is installed under high tension. It's suggested to loosen the bolt before removing the timing belt or motor mount. It's not a reverse thread, just really tight.

    Removal and reassembly of this bolt requires a counter-holding tool in order to counterhold and torque the bolt correctly. The following picture shows a counter-holding tool that is made for this application. It uses a 3/4" pipe as a handle. A 3-foot long pipe works well. Because of the force being applied to the joint where the pipe screws to the tool, it is best to clamp the pipe in a vise and turn the tool onto the pipe securely using a breaker handle or other suitable bar. When attaching the tool to the gear, matching the holes in the tool with the holes in the gear is made easier if the two indexing shoulder bolts are removed from the tool.

    After the four mounting bolts are snugged into the gear, the crankshaft may need to be turned one way or the other to be able to reinstall the two indexing bolts. After all six bolts are installed, tighten them securely. The crankshaft bolt uses a 19mm, 12-point socket. Use a pipe or other cheater for leverage as required to remove this bolt.

    (Be careful if using a big wrench as shown in this picture - use a straight pull to keep the wrench from slipping sideways off the breaker bar handle.) Because the right-side engine mount has been disconnected, the engine can move front-to-back and up-and-down. Using the tools close to each other, as shown, keeps the process stable.

    Once the bolt is wrench loose, remove the tool. You can remove the bolt and the gear after the timing belt is off, the counterhold tool is only needed for the very high torque on the bolt.

    Remove the timing belt. (See timing belt replacement procedure, for ALH engine see 1000q: ALH timing belt removal, for BEW engine see 1000q: BEW engine timing belt removal).

    If you are only replacing the crankshaft seal and not replacing the timing belt and related parts, the large timing belt roller must be removed. The roller sits in front of the upper portion of the carrier. When reassembling the roller, a new bolt must be installed because it is a stretch bolt. The torque for this bolt is 30 ft-lb + ¼ turn.

    Using a 10mm wrench, remove the ten bolts shown in this picture (6 on face, 4 on bottom).

    The carrier is now held to the engine by sealer and two locator pins. Remove the carrier from the engine by carefully prying straight out from the front of the block at the two locations shown in these photos. Do not pry between the carrier and the oil pan.
    crankshaft-seal-5.jpg crankshaft-seal-6.jpg

    Carefully clean the mounting surfaces of the block and oil pan, making sure to remove all of the old sealer. Also clean old sealer from the screw holes. The use of a shop vacuum helps control the debris. It is also helpful to wait to drain the old engine oil until after the carrier is reinstalled so any debris that does fall into the oil pan can be carried away with the oil. Use a degreaser to prepare the mounting surfaces for sealer adhesion.
    crankshaft-seal-7.jpg crankshaft-seal-8.jpg

    Clean the end of the crankshaft to prevent any damage to the new seal lip.

    Press the old seal from the carrier. Using an appropriately-sized socket or piece of wood and tapping with a hammer makes the process simple. You can wrap them in tape if you're worried about scratches.

    Thoroughly clean the entire carrier, making sure to remove all of the old sealer. Use a degreaser to prepare the mounting surfaces for sealer adhesion.

    Volkswagen specifies a product to use as an engine assembly sealant. It is identical to Victor Reinz Reinzosil. Use the VW sealer, Reinzosil or a similar quality sealer for this application. Apply two very small beads of sealer, one on each side of the block at the corner where the block and oil pan come together. Apply a small bead of sealer to the entire length of the back side of the carrier, inboard of the six bolt holes and two locator pins. Apply very small beads of sealer to the entire length of, and inboard of the screw holes of, the lower surface of the carrier and the oil pan, and with a clean index finger, smear both beads out so they are relatively flat. (A single larger bead of sealer applied to the carrier could be scraped off during assembly and would be ineffective. And placing a small amount of sealer on both surfaces ensures effective coverage.)
    crankshaft-seal-12.jpg crankshaft-seal-13.jpg

    Carefully, so as to keep as much sealer intact as possible, maneuver the carrier over the crankshaft and past the adjacent parts on the engine. Wiggle the carrier onto the two locator pins. Tap the cover on with a mallet at the locator pins. Install the ten mounting bolts and torque them to 11 ft-lb. It's normal to see a little bit of gasket maker squish out the sides. If a lot of gasket maker squishes out the sides it means you applied too much.

    Install the seal. If you are installing a PTFE (Teflon) seal, install it dry per the instructions that came with the seal. If you are installing a rubber seal, coat the lip of the seal and the crankshaft with a little engine oil.

    If you have a PTFE seal, assemble the seal per the instructions and using any assembly aids that came with the seal or VW tool T10053. Here is it in use on a PD engine. Guide sleeve T10053 fits over the crank snout. Then you can gently slide the seal over it until you feel slight resistance. Put drift T10053/1 over it and then gently tighten the old crankshaft bolt to push the seal forward until the drift comes to a gentle stop. Do not overtighten it, only tighten it until you feel resistance (the drift is plastic). When installed correctly the seal will rest just past the shoulder on the crankshaft so the timing belt gear does not contact it.

    If you have a rubber seal, use the guide sleeve VW# 2080a (looks similar to above but is black and slightly different diameter) and push it in with drift VW# 3265.

    Remove the guide sleeve and drift.

    Reinstall the crankshaft sprocket with a new bolt to loose-wrench tight. Use the counterhold tool to make sure the crankshaft cannot turn or else it may result in valve-piston contact! You just want the have the crankshaft sprocket tight enough to install the timing belt. Then remove the counterhold tool so you can gtet the timing belt back on.

    Reassemble the timing belt up until you put the crankshaft pulley back on. It's better to have the engine mount in place so that the engine cannot move before torquing the crankshaft bolt. Refer to the FAQ for your timing belt DIY.

    Place the timing belt gear onto the end of the crankshaft, matching the flats. Thread the new bolt into the end of the crankshaft until snug. Remove the two large shoulder bolts from the counter-holding tool and attach the tool to the timing belt gear using the four special hex socket head bolts. Index the holding tool to a position where the two shoulder bolts can be installed. Tighten all six bolts. Torque the new crankshaft bolt to 88 ft-lb.

    Next, pick a handy reference on the holding tool and place an identifying mark in a corresponding location on the head of the bolt. Advance the bolt an additional ¼ turn as shown below. (A cheater bar will be required.)

    Remove the counter-holding tool and continue with timing belt installation from crankshaft pulley installation.
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