850T5 Cam Followers

Assuming you know about the timing belt issues, then there's a couple of gotchas with taking the upper half of the head off (to get the cams out). If it doesn't come off evenly, i.e. if one side come up before the other, you'll break a little (very important) piece of the casting off. And it's glued down with a special sealer (no gasket) that needs to be spread evenly with a roller. And this sealer makes it tough to pull the upper part of the head up evenly, there's a special tool just for this job.

To add what Mike has knowledgeably said, you need a device (volvo tool or your own made one) to pull the top half back down onto the lower when you re-assemble (against the pressure of the valve springs) and also some wire both ends to fasten the cams to the top half as you lower them down. There is an off-centre slot in the dissy end of both cams you can slide a piece of flat metal into to lock them at 'tdc' position also.

You need about 8 pairs of hands at this stage!

The cam pulleys will need to come off, mark their position relative to the shafts with tippex or similar prior to releasing them- on some cars they are NOT keyed to the shaft. Beware.

I would strong recommend using the puller when releasing the top cover to ensure it comes up evenly- as Mike said you will break the casting if it does not. It is located on about 8 dowels and it can be tight to release, but sometimes they pop up of their own accord.

The tools I have are made a-la Haynes from 3 old plugs, the insultor and innards drilled out and some thread welded on with a cross piece and nut on the top. The cross piece straddles the cam cover. Install plugs in 1,3 and 5 and you can pull the upper half down squarely very easily, or conversely let it spring up evenly.

With respect to the sealer, Volvo sell both the removal thinners and the proper sealer stuff to re-assemble it with.

On *no* account *ever* use instant gasket, or worse silicone, or anything else. You will have leaks all over the shop if not worse. The Volvo sealer comes with a fine hair roller, which after you have removed the old sealer with the thinners you apply a very thin layer with the roller.

The new tappets must be soaked in clean engine oil for 24hrs first, and during this time use your fingers below oil level compress and release several times to prime them afew times.

Hope this helps.

Tim...