Oil valve stem seals

[volvo-express]

Hi everyone,

Is it possible to change the oil valve stem seals without removing the head.

They are not that bad but need to check the valve clearance as well. So if I can I'd like to do all the work together.

Thanks in advance for replying.

[v8volvo]

It is certainly possible. But it's a lot of work. Have to remove both timing belts, and the camshaft, and all 12 cam followers and valve springs/retainers/keepers, then put it all back together afterwards, including two new cam seals and the full timing belt installation procedure.

It is indeed easier than removing the head, though, IF valve stems seals really are all that's needed and if you are sure they are problematic now. For what it's worth though, those are not a very common issue. Are you seeing oil consumption that you have traced to the valve stems/guides? If not, it would be a lot of effort for something that might not give you any noticeable benefit.

Checking valve clearance is quite a simple job by comparison -- only have to remove the valve cover and use feeler gauges. No messing with the timing belts (unless they are already due anyway), no removing the cam, etc. If they need to be adjusted then it is more involved, need the shim kit and special tools to do that, but still pretty simple. There isn't really any overlapping work between valve clearance check and valve stem seal replacement, except maybe the removal and reinstallation of the valve cover.

Is there an issue you are looking for, or is this just for preventive care?

[RedArrow]

Unbelievable!
The same exact question came up in my mind yesterday or the day before.

My d24t wagon needs the timing belt job done in the near future and I was wondering if the valve stems seals were a great idea to add to that project.
UGH

I thought to myself, what if I did the valve stem seals even *before I do the timing belt job to make that day shorter and less complicated. But then I though that would be very counterproductive since the camshaft comes out for it so why separating the two major tasks?

Thanks for the good anwer And for the question too.

[volvo-express]

Thanks for replying.

Has anyone done it without taking off the head. I'm thinking about supporting the valves so it dosnt drop into the cylinder. Is it enough to have the engine on tdc on each cylinder to change seals?

I've seen other people putting rope into the cylinder to do this.

[ngoma]

Originally Posted by volvo-express

I'm thinking about supporting the valves so it dosnt drop into the cylinder. Is it enough to have the engine on tdc on each cylinder to change seals?

That probably could keep the valves up enough.

Originally Posted by volvo-express

I've seen other people putting rope into the cylinder to do this.

On the D24? How did they get the rope into the cylinder?

[v8volvo]

Originally Posted by volvo-express

Thanks for replying.

Has anyone done it without taking off the head. I'm thinking about supporting the valves so it dosnt drop into the cylinder. Is it enough to have the engine on tdc on each cylinder to change seals?

I've seen other people putting rope into the cylinder to do this.

Yes, sorry, I meant but failed to note in my earlier reply of course the removal of the keepers, retainers, and valve springs as well.

Yes, with these engines, due to the very limited clearance of valves to piston crowns at TDC it is no problem at all to use the pistons to hold the valves in position when you disassemble the valvetrain. I have used that method several times. Usually not specifically for valve stem seal replacement though -- the times I have had to do this is on PD TDI engines which have a tendency to wear holes in the tops of the followers due to excessively narrow cam lobes, and then the follower self-destructs and sends shrapnel down into the bottom of the follower bore that can only be fully cleaned up by taking off the spring/retainer/keeper assembly. D24T engines of course don't have this issue, but the method will work equally well for them.

Compressed shop air fed into the combustion chamber via the injector or glow plug opening (using a compression tester adapter) also works very well to keep the valves up, although then it involves even more labor to disassemble and reassemble those systems as well. Using the top of the piston is easier, as long as you are working carefully and don't lose track of what's going on inside the engine. You can make paint marks on the front crank pulley exactly 120 degrees apart so you don't have to guess about where the pistons are, and then do the six cylinders' valvetrain disassembly in three pairs working the crankshaft in the normal clockwise direction of rotation: 1/6, 2/5, 3/4, then return to #1/6 TDC to reassemble.

Again though, the big question is, are you certain these seals need to be replaced? This is a lot of effort and demands very careful attention to do it successfully, even without taking the head off. Lots of opportunity for risk and error too.

Only worth it if you are sure it's necessary. And if what it really needs is valve guides replaced also, then the head will have to come off regardless so you may as well do it that way. Valve stem seal leakage is fairly rare on these engines (though of course possible), but valve guide wear is quite typical.