300 Tdi valve stem seals

[damienb]

I replaced my valve stem seals about 5000 km ago in a process that ended up including a head gasket change.

The seals have now migrated upwards so the rocker gear is off.

How do you keep them down where they should be? Should I loctite them in?

The seals were Bearmach I think - whatever British Off Road supplies as default.

[rick130]

Just push them firmly back down onto the posts using a piece of tube, they'll stay there.

I had three migrate a long time ago, (7 years ?) the engine was using roughly 400ml/10,000km.
Changed all the stem seals with the head in situ and they were all still there where they should be when the head came off at the beginning of the year.

[muddymech]

Any pointers how to do this. My 200 tdi using oil im thinking valve stem seals.

[rick130]

Any pointers how to do this. My 200 tdi using oil im thinking valve stem seals.


You need a valve spring compressor that mounts and holds the spring from above.
The top bears on the retainer, two claws hook onto one of the lower winds of wire.
Obviously remove the rocker gear first. :D

Turn the engine over so that it is at TDC on the cylinder you are working on.
Having a flat head and large squish band, you don't need air to hold the valves up, but you must remember to have that piston at TDC or you are in for a world of hurt.

Compress spring, remove lash caps (if you haven't done so already) collets, retainer and spring and remove stem seals.

Lightly lubricate new seals and push onto posts.

Reassemble spring/retainer/collet assembly, and make sure the spring is sitting on the large washer at it's base and not hooked on the edge of the recess it sits in.

Reassemble rocker gear and lash caps, reset rocker clearances and you are all done.

Remember to keep everything in order as you undo things, and reassemble in order.

Keep everything clean and lube everything on reassembly.

[damienb]

Turn the engine over so that it is at TDC on the cylinder you are working on.
Having a flat head and large squish band, you don't need air to hold the valves up, but you must remember to have that piston at TDC or you are in for a world of hurt.


As I found out the hard way.

[rick130]

As I found out the hard way.
Ouch.

[damienb]

Having done this (again) today, it's pretty easy to avoid dropping a valve. Put it on TDC for the cylinder pair, and you can check when you compress the valve before you remove the collets that it only drops a couple of mm.

There are two seals - Bearmach (green) and Elring (brown). The Elring seem better quality and are probably OEM.

[ROAMER_AUS]

There was a video floating around showing when replacing these that they have to click into position. And you reckognise this by change of sound as you tap them in.

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