Actually, it's a bit more complicated that that.

Seal and slot must be prefectly clean. Install new cam seal in cover, sealing lip IN. Use the installation tool if you can find one so you don't nip any rubber off the new lip seal, else it will leak. Ofterwise, just be very carefull and lubricate seal with a bit of engine oil first.

Apply sealant to head where the cover will fit up, use the correct stuff ONLY (Locktite 5900?). Apply a dot to each end of the u-shaped bottom seal.

Wipe a small amount of synthetic grease on the bottom ONLY of the front cover so that it will slip over the seal. None on the back, you want the sealant to stick nicely there.

Place cover on head, engage the guide pins and slide on, holding pressure DOWN on the seal, don't allow the cover to pivot by pushing "straight" in on the guide pins. It actually tilts some if you do this, and tends to roll the seal over -- instant leak.

When on, before tightening the bolts, use a mirror and small flashilight and look at the seal through the slot between top cover and lower cover. Seal must be prefect. If suspicious, or has obvious spots where it rolled over, remove cover and try again.

Again, you must be careful that the camshaft seal doesn't get nipped at the same time.

It will eventually leak again anyway, but why hasten that problem?

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!