N62 Z3 Part 14: Engine Refresh (Valve Stem Seals)

And now the moment you've all been waiting for...


Valve stem seal tool installed

Spark plug removed. Dirty - likely original

Bungee cord shoved in the cylinder at BDC then the engine is turned over until it gets tight

Rocker arm slid off

Tool compresses the valve spring, revealing the valve keepers on the top of the valve

With the valve keepers removed

Then the tool is backed off, the spring assembly just removed by hand and the valve stem seal is accessible

With the valve stem seal removed. The area is also cleaned thoroughly - as the old seals deteriorate, leaving plasticized rubber bits behind, so its important to clean the area well so the new seal will seat properly

New elring klinger valve stem seal in place

Putting it all back together. On this particular valve, I got the keepers in on the first try, which felt like quite an accomplishment at the time and worth photographing but by the end - to be perfectly honest - I wasn't even using the tool. I didn't use the tool at all for the last 3 cylinders

This is the other exhaust valve on cylinder 1 - just a little better view of the new seal in place

My original plan was to completely do one valve stem seal as a proof of concept while I had some spare time one night. Then it was a kind of enjoyable process so I said ok lets do one cylinder... this is one of more accessible intake valves, this is the cylinder 1 intake valve

The area cleaned

New stem seal in place. Shown with the installation sleeve in place - the seals come with plastic sleeves you slide over the valves during installation, to protect the stem seal during installation

Then I was still having fun so I said hey lets do another cylinder. It didn't even occur to me until afterwards that technically, cylinder 2 is the "hardest" cylinder to do. With the rope method I didn't really have to think twice about it...

Very limited access and visibility on this cylinder. This upper raised assembly is the eccentric shaft - this is the Valvetronic assembly and how it varies the intake valve lift

View from below during removal

This area was difficult to clean the valve seat area but I figured out a method. My trick was to get the cloth draped around the backside of the valve, push it down into the seat area using my pliers, then pull it using downward force around the valve. This pulled the cloth around the valve and into the seat area and worked well to clean it

New stem seal in place

Keepers installed

The elring seals are supposed to be an improved design and possibly an improved material as well. However I did not notice any striking differences, although it was hard to tell what the original seals were supposed to look like and what was wear from ~100k miles. The elring seal do seem to have a couple extra ridges on the inside

Below is why cylinder 2 is the "trouble" cylinder. The video instructions say to leave it before TDC. The paper instructions say past TDC. Doing either, with air to hold the valves shut, leaves open the possibility of the engine doing one of two things: air forcing the engine to turn over (especially if past TDC) or air to leak past the opening in the valve and then lose air pressure in the cylinder (especially on the exhaust valve which don't have limited lift)


Either of those problems can cause the valve to drop into the cylinder and then your friendly neighborhood valve stem seal job becomes a full-on head gasket job as you need to remove the head to get the valve back out safely. So I was very relieved that the rope method worked well to avoid these issues. I think part of the reason for it working so well on cylinder 2 in particular is that you don't need the engine at TDC with the rope trick. The rope trick keeps the valves in place before TDC, well before TDC depending on how much rope you stuff in. You can vary the length stuffed in to vary where in the stroke the rope puts pressure on the valves. A few times, cam lobes got in the way so I would just pull some rope out to re-adjust. so I could rotate the engine over a little bit more which provided a lot of flexibility you don't have when working with air pressure. I don't think I will ever do this job with air

The first 8 that were done

You never really get a before and after shot with the valve stem seals because you have to do them one at a time - so this is about as close as you'll get. At the end I'll take a picture of all 32 of the old ones once they are out


The next day my yellow zinc plated nuts arrived for the intake manifold... GOOOOOLD

Test fit one to see how it looked. I'll need to clean the manifold a bit lol. When I got home later that day, a package from URO was there as well... the EPDM coolant pipe seals! It ends up, Viton does not play nicely long-term with Ethylene Glycol, which is a primary component of coolant. So the AGA "upgraded" seals I installed? Not so much an upgrade... URO contacted me about that after reading my build thread and sent seals for free as the coolant pipe has a lifetime warranty so that was pretty cool. So once the coolant seal is in, I can FINALLY button up the intake manifold for good and be done with the coolant pipe once and for all!

Then I went back to working on some valve stem seals... heres one of the hardest ones to do, pictured in place...

Halfway there!

And if you were curious how I was putting the keepers on without the tool...

Just using my long fingers... I'd get one on with a little grease (you use a little grease with the tool, too) and then spin it around to the opposite side, then pop the other one on

Taking a break from the valve steam seals to replace the coolant pipe seal with the proper seals from Uro

Uro EPDM seal in place