I'm replacing my strut cartridges on my 280z with KYBs. It's recommended to add some oil in the strut housing after inserting the new cartridge. The trouble is that there doesn't seem to be any seal up top. Just the large gland nut. Is that a problem?

KYB says you do not need to add oil to the tube but it's a good idea to add a small amount like 1/oz or so to keep the cartridge from rusting and sticking in the tube.

hmmm.... I did read that KYBs didn't need oil in the housing, but I prefred not to risk it. A small amount to coat the bottom is a good idea though!

Aside from the corrosion factor, the oil is to allow the heat from the cartridge to transfer to the strut tube.

Any motor oil will do. If it were me, i would add more than an ounce.

Oil is not needed. Modern shock oils can handle much higher working temps then what was used 20 years ago. I just put grease on the shock body so it will come out easier 10 years from now.

I added too much oil when I installed my cartridges recently and as the strut tips this way and that, and the oil warms and moves it tends to leak out a bit, puddling in the lower spring seat, then eventually leaking through the drain hole and down the side of the strut tube, making a mess. I'd follow John Coffey's advice, or only add a very small amount (like 1 ounce). You're correct that the gland nut doesn't seal.